High-Rise Residential Building using Cross-Laminated Timber Charlotte 9 th Street Tower- United States Case Study

Transcription

1 High-Rise Residential Building using Cross-Laminated Timber Charlotte 9 th Street Tower- United States Case Study Submitted by: The SFPE Student Chapter at the University of North Carolina at Charlotte April 2018 Prepared by Faculty Advisers Babak Bahrani, Christina Saunders, and Milad Shabanian Nicole L. Braxtan, Scott R. Rockwell, and Aixi Zhou Prepared for Society of Fire Protection Engineers (SFPE) 12 th International Conference on Performance-Based Codes and Fire Safety Design Methods April 23-27, 2018, Honolulu, Hawaii, USA

2 Acknowledgements This study was a group effort by three UNC Charlotte graduate students with diverse backgrounds and required a combined effort to bring innovative solutions to current industry challenges. The authors would like to thank the kind contributions of numerous individuals for their guidance and assistance during this case study (in alphabetical order): David Barber, principal fire safety and fire protection engineer at ARUP, who provided guidance regarding the fire design of CLT structures and serving as a thirdparty reviewer. David Impson, PE, and Graham Montgomery, of Britt, Peters and Associates in Greenville, South Carolina, who provided guidance concerning professionalism, engineering judgements, and design of the tall wood structure using CLT panels and glulam beams and serving as third-party reviewers. David Loy, vice president and principal at LS3P in Charlotte, North Carolina, who provided guidance regarding the architectural design and local code requirements. Gregorio Mesa and Jacob Kadel, graduate students in the Master of Fire Protection and Administration program at UNC Charlotte, for their assistance in fire modeling of the CLT Tower. Mahshid Shabanian; a special thank you for all her time and efforts developing the architectural renderings for our project. Her assistance is greatly appreciated. Charles Walker, PE, and Jeff Vernon, with the Mecklenburg County Code Enforcement Department in Charlotte, North Carolina, who provided guidance regarding the local code requirements. The SFPE UNC Charlotte Student Team would also like to thank their financial supporters at the University of North Carolina at Charlotte (listed in alphabetical order): James D. Bowen, PhD, Chair of the Civil and Environmental Engineering Department; Anthony L. Brizendine, PhD, PE, PS, Chair of the Engineering Technology and Construction Management Department; Robert E. Johnson, PhD, the Dean of William States Lee College of Engineering; Jy Wu, PhD, PE, PH, the Infrastructure and Environmental Systems (INES) Program Director; and the Graduate & Professional Student Government (GPSG) at UNC Charlotte. BABAK BAHRANI 1 Egress and Fire Design, Performance-Based Design President SFPE UNC Charlotte Student Chapter CHRISTINA SAUNDERS 2 Performance-Based Design, Fire Hazard Assessment, Architectural Design, Codes and Standards, Final Design Documentation, and LEED Member SFPE UNC Charlotte Student Chapter MILAD SHABANIAN 3 Architectural and Structural Design Member SFPE UNC Charlotte Student Chapter NICOLE L. BRAXTAN 4, PhD SCOTT R. ROCKWELL 5, PhD AIXI ZHOU 6, PhD, PE Faculty Advisers SFPE UNC Charlotte Student Chapter 9201 University City Boulevard Charlotte, NC USA 1 PhD Student- Infrastructure and Environmental Systems (INES) Department of Engineering Technology and Construction Management 2 MS Student- Master of Fire Protection and Administration- Department of Engineering Technology and Construction Management 3 PhD Student- Infrastructure and Environmental Systems (INES) Department of Civil and Environmental Engineering 4 Assistant Professor- Civil and Environmental Engineering- Department of Civil and Environmental Engineering 5 Assistant Professor- Fire Safety Engineering Technology- Department of Engineering Technology and Construction Management 5 Associate Professor- Fire Safety Engineering Technology- Department of Engineering Technology and Construction Management

3 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 TABLE OF CONTENTS LIST OF TABLES...vi LIST OF FIGURES... vii LIST OF ABBREVIATIONS... viii EXECUTIVE SUMMARY...ix 1. INTRODUCTION Project Background Current Tall Timber Buildings Status in the United States Research Projects Tall Wood Codes and Standards Design Constraints PROJECT SCOPE Stakeholders Building Description Building Overview Carpark Level P Carpark Level P Ground Floor Level L Typical Residential Floor Levels L2-L32 (Except L9, L17, and L25) Areas of Refuge and Amenities at Floor Levels L9, L17, and L Main Roof Sky Deck Penthouse Roof Building Codes and Standards Project Features Transient Use Accessibility Engineered Structural Wood Components Quality Assurance During Construction ENVIRONMENTAL CONSIDERATIONS FOR SUSTAINABILITY Environmental Goal Point Allocation Based on LEED Sustainable Site Development Water Savings Energy Efficiency Material and Resources Indoor Environmental Quality Green Building Elements iii

4 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference Sustainable Site Concerns Water Savings Concerns Energy Efficiency Concerns Materials and Resources Concerns Indoor Environmental Quality Concerns Carbon Footprint of Wood Structures Impact of Wood Use on Forests FIRE SAFETY GOALS, OBJECTIVES, AND PERFORMANCE CRITERIA Fire Safety Goals Fire Safety Objectives Performance Group Maximum Level of Damage to be Tolerated Risk Factors and Risk Assessment PRESCRIPTIVE CODES PERFORMANCE-BASED DESIGN AND ANALYSIS Methodology Building Characteristics The CLT Tower s Tenability Criteria Occupant Characteristics Egress Analysis Areas of Refuge Occupant Load Elevator Evacuation Design Evacuation Strategies DESIGN FIRE SCENARIOS Design Fires Scenario 1- Typical Occupancy-Specific Design Fire Scenario Scenario 2- Ultra-Fast Developing Fire in the Primary Means of Egress Scenario 3- Fire in an Unoccupied Room near a High-Occupancy Place Scenario 4- Concealed Space Fire near a High-Occupancy Space Scenario 5- Slow Developing Shield Fire near a High-Occupancy Space Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load Scenario 7- Outside Exposure Fire Scenario 8- Failure of the Fire Protection Systems TRIAL DESIGNS AND EVALUATION Trial Designs Trial Design Evaluation iv

5 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference Design Fire Scenario 1- Typical Occupancy-Specific Design Fire Scenario Design Fire Scenario 5- Slow Developing Shield Fire near a High-Occupancy Space Design Fire Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load Scenario Fire 8- Failure of the Fire Protection Systems Comparison of Fire Simulation to Fire Safety Goals and Objectives FINAL DESIGN DOCUMENTATION General Fire Protection Features Operations and Maintenance Manual Fire/Emergency Plan Fire and Life Safety During Construction REFERENCES APPENDIX A- Floor Plans... A-1 APPENDIX B- Hazard Analysis... B-1 APPENDIX C- LEED 2009 Tower Certification Requirements and Credits... C-1 APPENDIX D- LEED 2009 Tower Daylight and Views Calculation Summary... D-1 APPENDIX E- CLT Tower Building Characteristics... E-1 E.1 Architectural Features... E-1 E.2 Structural Components... E-3 E.3 Fire Load... E-4 E.4 Egress Components... E-4 E.5 Fire Protection Systems... E-5 E.6 Building Services and Processes... E-5 E.7 Operational Characteristics... E-6 E.8 Fire Department Response Characteristics... E-6 E.9 Environmental Factors... E-6 APPENDIX F- Operations and Maintenance Manual... F-1 F.1 Responsibilities of the Fire Safety Manager... F-1 F.2 Fire Protection Features of the CLT Tower... F-1 F.3 Evacuation Plan... F-4 F.4 Fire Safety Checklist... F-6 F.5 Life Safety and Fire Protection System Maintenance... F-7 F.6 Required Inspections... F-7 APPENDIX G- Fire/emergency Plan... G-1 G.1 Fire/Emergency Procedures... G-1 G.2 Hurricanes/Floods Procedures... G-2 G.3 Bomb Threat Procedures... G-3 G.4 Description of the Building and the Protection Systems... G-4 G.5 Duties and Responsibilities of Emergency Evacuation Personnel... G-7 v

6 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 APPENDIX H- Fire and Life Safety During Construction... I-1 APPENDIX I- Third-Party Review... I-1 vi

7 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 LIST OF TABLES Table 1.1 Table 1.2 Table 2.1 Table 4.1 Table 6.1 Table 6.2 Table 6.3 Table 6.4 Table 6.5 Table 8.1 Table 8.2 Table 8.3 Table 8.4 Table 8.5 Table B-1a Table B-1b Table B-2 Table B-3 Table B-4 Table B-5 Table B-6 Table B-7 Table B-8 Table B-9 AD-TWB Suggestions on Type IV Construction Features The CLT Tower's Occupancy Classifications Advantages of Using Mass Timber as a Construction Material Maximum Level of Damage to be Tolerated, Design Event Magnitudes, and Impacts for Performance Group III Tenability Criteria Occupant Load Zones and Exit Discharge Levels Input Values for Elevator Evacuation Exit Discharge and Travel Time for the CLT Tower Physical Properties of Canola Oil Design Fire Scenario 1 Summary Design Fire Scenario 5 Summary Design Fire Scenario 6 Summary Design Fire Scenario 8 Summary Matrix for Ranking Green Building Fire Hazards The Fire Hazards and Level of Impact for the Tower s Green Building Elements Mitigation Strategies for Site Selection Category Mitigation Strategies for Water Savings Category Mitigation Strategies for Energy Efficiency Category Mitigation Strategies for Materials and Resources Category Mitigation Strategies for Indoor Environmental Quality Category Matrix for Ranking Green Building Fire Hazards with Mitigated Strategies The Fire Hazards and Level of Impact on the Tower after Mitigation Strategies Greatest Impact Reductions after Mitigation Strategies vi

8 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 LIST OF FIGURES Figure 1.1 Figure 1.2 Figure 2.1 Figure 2.2 Figure 2.3 Figure 2.4 Figure 2.5 Figure 3.1 Figure 3.2 Figure 3.3 Figure 4.1 Figure 6.1 Figure 6.2 Figure 6.3 Figure 8.1 Figure 8.2 Figure 8.3 Figure 8.4 Front Elevation of the CLT Tower Aerial Image of the CLT Tower Crosswise Layers of Timber Boards Example of a Glulam Beam Platform vs. Balloon Framing Typical Mechanical Concealed Connection Char Layer and Pyrolysis Zone in a Timber Beam LEED 2009 Checklist for the 9th Street CLT Tower CO2 Emissions of Typical Construction Materials over Full Life-Cycle Forest Distribution across the Globe Contribution of Risk Factors to Total Lifecycle Carbon Emissions Time to Incapacitation during Exposure to HCN and CO Elevator Evacuation Steps Evacuation Strategies in the CLT Tower Design Fire Scenario 1- Residential Kitchen Fire Design Fire Scenario 5- Slow Developing Fire near a High-Occupancy Space Design Fire Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load Design Fire Scenario 8- Failure of Sprinklers in a Residential Area vii

9 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 LIST OF ABBREVIATIONS ADAAG AH-TWB AHJ ANSI ATF AWC CCWD CLT FCC FDC FDS FPRF FSC GLULAM IBC ICC ICCPC IFC LEED NDS NFPA NIST NLT OEE OEO SFPE SwRI TWB UMUD American with Disabilities Accessibility Guidelines Ad Hoc Committee on Tall Wood Buildings Authority Having Jurisdiction American National Standard Institute Bureau of Alcohol, Tobacco, Firearms and Explosives American Wood Council Code Confirming Wood Design Cross Laminated Timber Fire Command Center Fire Department Connection Fire Dynamics Simulator Fire Protection Research Foundation Forest Stewardship Council Glue Laminated Timber International Building Code International Code Council International Code Council Performance Code International Fire Code Leadership in Energy and Environmental Design National Design Specifications for Wood Construction National Fire Protection Association National Institute of Standards and Technology Nail Laminated Timber Occupant Evacuation Elevator Occupant Evacuation Operation Society of Fire Protection Engineers Southwest Research Institute Tall Wood Building Uptown Mixed-Use District viii

10 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 EXECUTIVE SUMMARY The Society of Fire Protection Engineers (SFPE) provided a case study specification for a performancebased design of a high-rise building using cross-laminated timber (CLT), presented at the 12 th International Conference on Performance-Based Codes and Fire Safety Design Methods in Honolulu, Oahu, Hawaii on April 23-27, The performance-based analysis includes the building description, transient use and CLT features, environmental considerations for sustainability, performance criteria, floor plans, trial designs, and final design document. The prescriptive building and fire codes governing this project include the 2015 International Building Code (IBC) and 2015 National Fire Protection Association (NFPA) 101 Life Safety Code. The structural design for the CLT wood framing members is in accordance with the American Wood Council (AWC) 2018 National Design Specification for Wood Construction (NDS). The SFPE Engineering Guide to Performance-Based Fire Protection was also used for the framework of the final report. The 32-story, 93-m (305-ft.) tall building, located in a financial district of Charlotte, NC, is residential with retail incorporated on the ground floor and two carpark levels below ground. The target market for the building is members of the gig economy and maximizes transient use. The building owner has requested the highest possible environmental standard of sustainability for the project and Occupant Evacuation Elevators (OEE) for emergency situations. The structural behavior of the CLT during a fire event is addressed, and there is an architectural design feature exposing parts of the CLT. The Tower is designed as a mixed-use structure, including the following occupancy classifications: Assembly, Business, Mercantile, Storage, and Residential. The target market for the Tower is members from the gig economy transient workers with short-term positions. In addition, the Tower incorporates a green (sustainable) design. The Leadership in Energy and Environmental Design (LEED) 2009 Green Building Rating System for New Construction is used to evaluate the environmental performance, from a whole building perspective, of the Tower. CLT has numerous advantages over other typical construction materials; yet, public perception and current code restrictions in the United States limits the construction of buildings higher than 6 stories (75 ft.). Thus, building is designed the way that meets the fire safety goals and objectives, including: Protecting occupants (transient, permanent, and staff) against fire incidents Protecting firefighters while fire suppression and rescue operation Maintaining the structure s integrity in a fire event Preventing fire spread to adjacent buildings in a fire event In addition, the performance-based design for the Tower addresses the following building features: ix

11 High-Rise CLT Building- SFPE UNC Charlotte- USA SFPE Performance Based Design Conference 2018 Tall building with a structural timber system Exposed timber features Transient occupants Occupant evacuation elevators Sustainable design A semi-quantitative fire hazard assessment for the green building initiatives is proposed for the Tower, assigning values to selected variables, based on professional judgment and experience. Parameters associated with the fire hazards of the above listed LEED categories are identified as performance concerns for the Tower and the façade. The semi-quantitative approach uses a widely recognized index method, establishing an order of magnitude, with relative rankings. Some parts of the CLT Tower are exposed as an architectural feature. Walls are equipped with total encapsulation which provides a 3-hr. fire resistance rating. The tower is also equipped with a 2-hr. fire resistance rated stairwell, and a1-hr. fire-resistance rated smoke barrier elevator lobby. It is also equipped with a mechanical ventilation to the roof as the main smoke management strategy. Performance Group III was determined for the CLT tower based on ICCPC, and the following tenability criteria was developed and analyzed in the trial designs: Radiant Flux Max. 2.5-kW/m2 (793-Btu/ft.2/hr.) at Head Height (1.8-m or 5.9-ft.) Elevated Air Temperature 60 ºC (140 ºF) for 30-Minutes Exposure to Air Saturated with Water Vapor Elevated Smoke Temperature 60 ºC (140 ºF) for 30-Minutes Exposure Visibility Distance Max. 10-m (33-ft.) to Doors and Walls Smoke Toxicity (CO Concentration) Average of 1000-ppm for the First 20-Minutes of Exposure Smoke Toxicity (Hydrogen Cyanide) Max. 100-ppm for the 20-Minutes of Exposure To ensure the proper life safety in a fire event, three refuge floors (L9, L17, and L25) were design in the CLT Tower. The areas of refuge are completely encapsulated and provide a 3-hr. fire resistance rating. Additionally, areas of refuge are designed at all stairway connections to floors with a 1-hr. fire resistance rating. The CLT Tower design prioritized the life safety of firefighters and occupants with mobility impairment. The main egress strategy for the tower is elevator evacuation. Thus, egress analysis was performed based on two strategies: zone and total evacuation. Computer modeling using Elevator Evacuation (ELVAC) was performed to evaluate the performance criteria. The results were also compared to hand calculations of the Occupant Evacuation Elevators (OEE) strategy. 8 design fire scenarios were developed, and 4 were evaluated using the Fire Dynamics Simulator (FDS) and PyroSim. Trial designs, egress analysis, and design fire scenarios were then combined and compared to fire safety goals and objectives. Findings based on these evaluations demonstrated an adequate level of life safety for both transient and permanent occupants. x

12 1. INTRODUCTION 1.1. Project Background The Society of Fire Protection Engineers (SFPE) provided a case study specification for a performance-based design of a high-rise building using cross-laminated timber (CLT) for the 12 th International Conference on Performance-Based Codes and Fire Safety Design Methods. The building, located in a financial district of a large city, is residential with retail incorporated on the ground floor and two carpark levels below ground. The project s objective statement includes: performance goals, a basic building description, and minimum requirements. The target market for the building is members of the gig economy and must maximize transient use. In addition, flexibility must be provided to facilitate permanent occupants. The building owner has requested the highest possible environmental standard of sustainability for the project and Occupant Evacuation Elevators (OEE) for emergency situations. The structural behavior of the CLT during a fire event should be addressed, and there is an architectural desire to expose parts of the CLT as a design feature. The UNC Charlotte SFPE Student Chapter Team identified additional assumptions and completed a performance-based analysis of the building. A proposed final design has been developed, including recommendations for fire and life safety features to provide a design solution that conforms to the intent of the building code, ensures the project goals and objectives are met, and provides a level of safety, reliability and durability intended by a prescriptive solution [25]. The recommended fire safety design features contained in Section 9.1 are to be implemented properly. 1.2 Current Tall Timber Buildings Status in the United States The growing interest in mass timber as a construction material in the United States has led to a series of research and case studies nationwide. This interest raised awareness of the lack of proper codes and guidelines for mass timber, especially in the case of exposed sections that may contribute to the fire load during a fire incident Research Projects A number of major studies have been performed on the fire performance of mass timber construction in the United States through the end of These tests included standardized, compartment, and noncombustible protection tests. The standardized tests were performed based 1

13 on ASTM E84: Standard Test Method for Surface Burning Characteristics of Building Materials, ASTM E119: Standard Test Methods for Fire Tests of Building Construction and Materials, ASTM E114: Standard Practice for Ultrasonic Pulse-Echo Straight-Beam Contact Testing, and NFPA 285: Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components American Wood Council (AWC) An investigation of fire performance of non-exposed CLT wall assemblies was performed in compliance with ASTM E119-11a: Standard Method of Fire Testing of Building Construction and Materials, in 2012 for the American Wood Council (AWC) [1]. The test setup components consisted of 5-ply CLT wall panels and gypsum sheathing a single layer of 5/8-in. type X gypsum board on both sides of walls. A total load of 87,000-lbs. was applied to the assembly using 8 hydraulic jacks. Data was recorded using 9 type J thermocouples located on the unexposed surface of the wall assembly, and 10 type J thermocouples located between the CLT walls and the gypsum boards. Results showed that the structural failure occurred 3-hours, 5-minutes, and 57-seconds into the test while the panel was still carrying the load. In addition, the average recorded temperature for 9 unexposed thermocouples was 22 ºC (71 ºF) and maximum temperature was 23 ºC (74 ºF) Southwest Research Institute (SwRI) ASTM E814 Test SwRI used 5-ply CLT as part of their test assembly to evaluate the performance of fire stop materials while exposed to external fires in 2015 [2]. The CLT panels were covered with two layers of 5/8-inch type X gypsum boards. Results showed that the three through-penetrations achieved 2- hr. fire rating, and the temperature in neither of them increased 132-ºC (270-ºF). The tests are regulated by IBC in sections and [3]. The experimental procedure was compliant with ASTM E814-13a- Standard Test Method for Fire Tests of Penetration Firestop Systems Compartment Test A number of full-scale tests were performed in SwRI in 2015 to evaluate the fire performance of protected CLT. 7-in thick CLT walls were protected with two layers of 5/8-in. (16-mm) type X 2

14 gypsum boards, with a ceiling made of Nail Laminated Timber (NLT) also covered with two layers of 5/8-in. (16-mm) type X gypsum boards [4]. Concrete blocks applied a distributed load of 1.9- kn/m 2 (40-psf.) on the ceiling. To represent a compartment fire, the room was furnished with upholstery and common residential contents such as chairs, bookcases, TV, and rug. Two tests were performed; the compartment was completely burnt 3-hours into the test. Recorded temperatures from thermocouples showed that the temperature did not exceed 100 ºC (212 ºF) between the base gypsum layer and the CLT and/or NLT panels, where the highest recorded temperature in both tests was 269 ºC (516 ºF) that recorded from thermocouples between the two gypsum board layer. Post-test observation indicated that the base gypsum board layer remained mostly intact (except the corners). In addition, no noticeable penetration into CLT laminas was observed in neither of the tests NFPA Fire Protection Research Foundation (FPRF) The objective for this test was to evaluate the contribution of exposed CLT to fire loads in order to collect data for insurance modeling. Tests were performed by National Research Council (NRC) Canada at NIST facilities. A series of unsprinklered compartment fire tests were performed to evaluate the severity and fire impacts in presence of CLT [5]. Two studio-sized compartments were constructed from 5-ply, 175- mm thick CLT panels for both walls and ceiling assemblies. Compartments were either fully or partially encapsulated with 2 or 3 layers of 5/8-in. (15.9-mm) type X gypsum boards Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) 5 full-scale compartment tests were performed in 2017 to evaluate the performance of buildings constructed from mass timber. Tests examined the effects of exposed wall and ceiling assemblies on a compartment [6]. The test setup included a two-story CLT building, with a range of total encapsulation (100%) to no encapsulation. Walls were constructed of 5-ply, 175-mm (6.89-in.) CLT panels. The first floor did not include any CLT assembly and was protected with two layers of 12.7-mm (1/2-in.) thick cement boards. The second level ceiling was constructed of the same 5-ply CLT panels as the wall assemblies in the first and second story. Beams and support columns were constructed of glulam, 3

15 protected with wood cover, compliant with chapter 16 of NDS in the first floor. They were protected with two layers of 15.9-mm (5/8-in.) type X gypsum board in the second floor. All the wall assemblies and the ceiling was protected in one of the tests, but one or more of the walls and the ceiling was either partially or totally exposed in the remaining 4 tests. Common residential contents were present in the compartment fire tests. In addition, 3 of the tests were performed in absence of sprinklers. Results from these tests showed that encapsulated CLT surfaces did not significantly contribute to the fire load. However, the contribution was increased as the exposed surface was larger (in absence of sprinklers). The protected mass timber surfaces were mostly uncharred after the tests. Experiment showed the self-extinguishment of CLT assemblies in the decay phase. In addition, it was seen that each layer of 15.9-mm (5/8-in.) type X gypsum board could resist the fire for at least 40 minutes Tall Wood Codes and Standards ICC Tall Wood Building (TWB) Ad Hoc Committee The Ad Hoc Committee on Tall Wood Buildings (AH-TWB) started working in December 2015 to investigate the science, feasibility, and code requirements for tall wood buildings [7]. The committee have had 6 meeting prior to March 31, 2018; the day for submitting this case study. Members developed a draft for potential changes in the 2018/2019 edition of the IBC regarding the CLT definition, allowable building height, fire-resistance rating, construction classification, minimum standards and quality, and general construction requirements [8]. The results from previous fire tests are used by the AH-TWB for further recommendations on using mass timber as a construction material in the IBC AH-TWB proposed 15 code changes for the next cycle. Noteworthy to mention, the group suggest 3 new categories for type IV construction, considering the level of exposure of the mass timber in construction [81] : Type IV-A: Mass Timber with Non-Combustible Protection Type IV-B: Mass Timber with Portions of Non-Combustible Protection Omitted Type IV-C: Mas Timber with No Requirement for Non-Combustible Protection, except Certain Features 4

16 The committee also proposed the total or partial encapsulation of mass timber elements, where protection contribution of ½-in. Type X gypsum board and 5/8-in. Type X gypsum board is considered 30-min. and 40-min., and up to 3 layers of protection is predicted [81]. In addition, AH-TWB proposed the suggested heights and features for new type IV constructions. These suggestions are summarized in Table 1.1 [81]. Table 1.1 AD-TWB Suggestions on Type IV Construction Features Construction Type Building Element IV-A IV-B IV-C Max. Height 82.3-m (270-ft.) 52.9-m (180-ft.) 25.9-m (85-ft.) Number of Stories Exposed Mass Timber None Fully Protected Yes Partially Fully Exposed Sprinklers Fire-Resistance from Non- Combustible 120-min. Yes 80-min ANSI/APA PRG 320 In absence of a specific standard on CLT, APA The Engineered Wood Association has used several US, Canadian, and international standards on wood construction and wood products to develop the ANSI/APA PRG 320: Standard for Performance-Rated Cross-Laminated Timber; also approved by the American National Standard Institute (ANSI). The standard was first published in 2012, with subsequent versions in 2017 and the most recent version, Per AH-TWB recommendations for further IBC versions ( ), CLT manufacturing should be compliant with ANSI/APPA PRG 320 [8]. 1.3 Design Constraints Current codes and standards do not directly address the requirements for timber buildings higher than 6 stories in US. ASTM E119 is also not a proper representative for such structures for numerous reasons including, but not limited to: ASTM E119 only covers the heating phase of fires, not the decay phase Recent compartment fire tests showed that time to reach the peak temperature is significantly smaller in comparison to ASTM E119, which takes more than 4 hours for gradual temperature rise. One other main concern in mass timber structure fire performance is burnout [68]. More studies are necessary to evaluate the fire behavior in such structures especially in the decay phase. Code 5

17 acceptance is a time-consuming process, and research and standardized design methods are still in progress in North America [70]. The Ad Hoc Committee on Tall Wood Buildings (AH-TWB) started in late 2015 to address concerns regarding the mass timber construction, and proposed changes to the next version of IBC to be published in Stakeholders 2. PROJECT SCOPE Due to the large and complex nature of this project, the stakeholders of the project were consulted early in the design process; the primary stakeholders include: The property owner The insurance carrier(s) The financial lender The architectural firm The engineering firm specializing in tall timber structures City of Charlotte, North Carolina, is the Authority Having Jurisdiction (AHJ) enforcing all applicable regulatory codes governing the construction of the project The Charlotte Fire Department is the response agency for emergency incidents at the tower The fire protection engineer The primary stakeholders meet weekly during the design phase of the project to ensure completeness in the design and to maintain the project schedule. A third-party review will be conducted to undertake inspections of completed installations [1] in accordance with The SFPE Guidelines for the Peer Review in the Fire Protection Design Process Building Description Building Overview The 32-story, 93-m (305-ft.) tall building located in Charlotte, North Carolina, USA, incorporates a structural concrete podium design with CLT balloon framing, eliminating hidden voids at the structural connections. There are two carpark levels below grade constructed from precast concrete and a 30-story structure above grade constructed using a CLT engineered wood system to create a wood-concrete concept [19]. The tower is rectangular with exterior dimensions of 40 m (131-ft.) 40 m (131-ft.) with a total footprint of approximately 1600-m 2 (17,227-ft.²) per floor, and a floorto-floor height of 3 m (9.8-ft.). A green (sustainable) design is incorporated into the expression of the building; measures such as vegetated open spaces on the roof and proximity to a planned light 6

18 rail station alleviate many zoning restrictions, including carpark requirements. The tower is designed as a mixed-use structure and incorporates several occupancy classifications as summarized in Table 1.1. Table 1.2 The CLT Tower's Occupancy Classifications Occupancy Class Description A- Assembly B- Business M- Mercantile A-1 Theatre A-3 Gymnasium, and Community Halls S- Storage S-2 Parking Garage (Open or Closed) R- Residential R-1 Transient R-2 Apartment Houses Parking is located beneath the Tower and is designed for resident-use only. In addition, the building owner provides lease agreements for additional carpark spaces in off-site parking structures and lots no further than 490-m (1,600-ft.) away. Parking for retail is on the street in front of the building with a drop-off lane for ride-share services. A central reinforced concrete shear wall core houses and protects 4 passenger elevator cars, one service elevator car, and one exit stairwell. A 1-hr. fire-resistance rated smoke barrier elevator lobby and trash chutes connected to the basement for disposal are designed on each level. Each passenger elevator car is enclosed within a 2-hr fire resistance rated construction and operates independently from the other elevators. The Tower has one exit stairwell enclosed in a 2-hr. fire resistance rated enclosure serving all floors and the Sky deck roof. In the event of a fire, residents are to move out of the effected smoke compartment into the elevator lobby. 7

19 Figure 1.1 Front Elevation of the CLT Tower The occupants self-evacuate vertically in one of the 4 passenger elevator cars to the ground floor and, if necessary, outside of the building. The service elevator is designated for use by the fire fighters during an emergency. The exit stair enclosure, each elevator s hoist way, and the elevator lobbies are pressurized to reduce the smoke spread during an emergency movement. The building site is at th Street and is the basis for naming the building the 9 th Street Tower (see Appendix A). It is centrally located on a rectangular building site with a 2-m separation distance to all four adjacent property lines. An exterior rendering of the Tower elevation is shown in Figure 1.1,, an aerial image is shown in Figure 1.2, and conceptual drawing schematics for the case study are provided in Appendix A. A description of the use for each floor level is provided below: 8

20 Figure 0.1 Aerial Image of the CLT Tower Carpark Level P2 This below-grade level has an open-plan design and consists of vehicular parking spaces, of which 4 are designated accessible parking spaces. This level is accessed by one remotely located exit stair enclosure, 4 passenger elevator cars, and one service elevator. This level houses critical utility infrastructure, such as the main electrical room, emergency electrical room, gas room, fire pump, and domestic/fire protection water service. These rooms are enclosed in 2-hr. fire-resistive construction with 1½-hour rated self-closing fire doors. An emergency generator for the building is also located on this level. The generator is fueled by natural gas and has the capacity to serve the critical building systems, such as the fire alarm, smoke control systems, elevators, and emergency lighting. Greywater will be recycled and stored below this level for non-potable uses such as irrigation Carpark Level P1 This below-grade level also has an open-plan design and consists of vehicular parking spaces, 3 are designated accessible parking spaces, and 5 are designated preferred parking for low-emitting and/or fuel-efficient vehicles. This level incorporates a vehicular exit driveway on the north side of the tower. This level is accessed by one remotely located exit stair enclosure, 4 passenger 9

21 elevator cars, and one service elevator. A bicycle storage facility is located near the carpark entrance on this level. A single loading area is also provided near the service elevator. A shareparking area is located at the carpark entrance, includes a carpool drop-off area, car-share services with designated parking for vanpools, and an off-street service/delivery parking space. The backof-house space also resides on this level, includes the parking attendant room, maintenance office with workroom, and a separate maintenance storage room. The maintenance rooms are enclosed in 1-hr. fire-resistive construction with ¾-hr. rated self-closing fire doors Ground Floor Level L1 This floor is at grade level and is assigned as the entrance and exit discharge level. The west side of the Tower has a recessed vestibule exit through the lobby area and serves as the main entrance to the building. The south, east and north sides each have a recessed exit to the exterior at grade also. Retail areas are located along the perimeter of the ground floor, where each retail space has direct access to the outside. Each retail area is designed as a closed-plan space and is separated by a 3-hr fire-rated demising wall. The lobby includes a special architectural design feature: exposed Glue Laminated Timber (Glulam) columns. A management office and security/reception desk are provided on this floor level near the lobby; all resident visitors are required to sign in to gain access to the residential floors. The exterior perimeter of the Tower is provided with a large, heavy timber planter barrier to minimize the risk of a vehicle ramming into the building. This level is accessed by one remotely located exit stair enclosure, 4 passenger elevator cars, and one service elevator. The elevator hoist way is open to the lobby area; adjacent is the housekeeping room, enclosed in a 1-hr. fire-resistive construction with a ¾-hr. rated self-closing fire door. The Tower is provided with a dedicated Fire Command Center (FCC) on this level, enclosed in a 2-hr fire resistance rated construction. The FCC is located adjacent to the south side exit enclosure; access is from the lobby or directly from the exterior. A Fire Department Connection (FDC) is located at this level, as well. The exit access corridors are enclosed in 1-hr. fire-resistive construction and all corridor doors are 1-hr. rated self-closing fire doors. A utility/ smoke shaft, that could be manually opened by the fire department or remotely opened from manual controls in the FCC, is located at each end of the exit access corridor. The utility/smoke shafts are enclosed in 2-hr. fire-resistive construction with 1½-hr. rated automatic-opening fire doors by remote control from the FCC. 10

22 Typical Residential Floor Levels L2-L32 (Except L9, L17, and L25) These levels each consist of 10 single-story, semi-open floor plan condominium apartment units. They include a blend of sizes: four 3-bedroom units of approximately 150-m 2, four 2-bedroom units of approximately m 2, and two 1-bedroom units of approximately m 2. Each residential unit is separated by a 3-hr. rated demising wall. Each unit is also separated from the corridor areas by a 3-hr. fire rated demising wall. The residential floor levels are accessed by one remotely located exit stair enclosure, 4 passenger elevator cars, and one service elevator. Each residential floor level is provided an area for housekeeping/ maid services, a dry-cleaning pick-up/ delivery station, and a reading lounge with vending machines. All units have a 2.5-m wide exterior balcony, continuous around the perimeter of the Tower, with privacy walls between each unit s balconies. In addition, all residential units include an exposed CLT ceiling in all areas, except the kitchens and bathrooms, as a unique architectural feature. Mandatory elevated temperatures performance tests for CLT adhesives, per ANSI/APA PRG , is required for the floor/ ceiling slabs; where the exposed slabs should maintain desire load for a 240-minutes period in a cooling phase of a fully-developed compartment fire [9]. The CLT panels on the kitchen and bathroom ceilings have complete encapsulation using gypsum boards to provide a 2-hr. rated fire resistance. The CLT floors are covered with a 55-mm, lightweight gypcrete coating. The exit access corridor is enclosed in a 2-hr. fire resistance rated construction. All corridor doors are 2-hr. rated, self-closing fire doors Areas of Refuge and Amenities at Floor Levels L9, L17, and L25 The Areas of Refuge and the building amenities are located on floor levels L9, L17, and L25. The areas of refuge are separated from the corridor area by a 3-hr fire-rated demising walls. The building amenities include: an open-plan fitness center on all three floor levels; a cinema on level L9; a game lounge and coffee bar on level L17; a business center, reading lounge, and a salon on level L25. These levels include a 2.5-m wide exterior balcony, continuous around the perimeter of the Tower, with privacy walls between the amenities balconies. These floor levels are only accessible to the building residents and building employees. The floors/ceilings on these three floor levels are mm (6-in.) thick concrete for fire separation, acoustics, and structural floor vibration requirements. These levels are compartmentalized into 4 smoke compartments by four, 1-hr. fire-resistance rated smoke barriers. Access to the exit stair enclosure is through the enclosed 11

23 elevator lobby on these three levels. Floor levels L9 and L17 include partially mechanical spaces containing utilities to serve the building. Storage tanks for captured rainwater are also located on these three levels. The water back feeds to lower floors to provide an auxiliary method of delivering full fire protection demand for the system in the event of a pump failure Main Roof Sky Deck The sky deck is served by a single exit stair enclosure accessed from the lobby on Level 32. The central core of the tower extends above Level 32, creating a penthouse to accommodate access to the sky deck. In addition to the stair enclosure, the penthouse also contains separate HVAC rooms to pressurize the exit stair enclosure, elevator hoist ways, and the enclosed elevator lobbies. The sky deck incorporates a low maintenance vegetated green roof as an open space; a 1m tall parapet extends above the perimeter of the flat terrace roof. This level is only accessible to the building residents and building employees. The maximum occupant load permitted on the sky deck at one time is 50 people, including staff members; security is provided to limit the access to the sky deck. Rainwater will be captured and stored in tanks on the sky deck roof in addition to the amenity floors. The water back feeds to lower floors to provide an auxiliary method of delivering full fire protection demand for the system in the event of a pump failure Penthouse Roof The penthouse roof is served by a single exit stair ladder, accessed from the penthouse on the main roof sky deck. This level is accessible only to the building employees and maintenance personnel. The penthouse roof incorporates an on-site Photovoltaic (PV) renewable solar power energy system Building Codes and Standards The prescriptive building and fire codes governing this project include the 2015 International Building Code (IBC) [3], the 2015 National Fire Protection Association (NFPA) 101 Life Safety Code [10], and the 2015 International Fire Code (IFC) [11]. The structural design for the CLT wood framing members is in accordance with the American Wood Council (AWC) 2018 National Design Specification for Wood Construction (NDS) [12]. The sprinkler system meets the requirements of the National Fire Protection Association (NFPA) 13, Standard for the Installation of Sprinkler Systems [13], and the standpipe system meets the requirements of NFPA 14, Standard for the Installation of Standpipe and Hose Systems [14]. The emergency voice/alarm communication 12

24 system provided throughout the building is in accordance with NFPA 72, National Fire Alarm and Signaling Code [15]. Fire extinguishers are placed throughout the building in accordance with NFPA 10, Standard for Portable Fire Extinguishers [16]. Both prescriptive codes and performance codes were used for this project. Accessibility standards for the Tower conform to the 2010 Americans with Disability Act (ADA) Standards for Accessible Design [18]. The Tower owner has contracted with a third-party peer review agency to evaluate the performance-based design for compliance Project Features Transient Use The target market for the Tower is members from the gig economy transient workers with shortterm positions. The way Americans work is rapidly changing as the traditional workflow has been augmented by a maturing gig economy over the last decade [92]. In 1995, alternative employment arrangements accounted for 9.3% of U.S. employment [88], while, nearly 57.3 million Americans, or 36% of the nation's workforce, are now transient workers [87] and is expected to increase to 43% by 2020 [87, 92]. This innovative economy is now affecting the way we use residential buildings, requiring new design strategies [92]. In addition to the traditional permanent (long-term) occupancy, flexibility is also provided to facilitate transient (short-term) use at the 9 th Street Tower. These short-term, transient dwelling units, require different building code and zoning standards; they are required to be safer because the occupant is less familiar with the building layout and emergency safety measures than permanent residents [86]. As a result, fire safety, egress, elevators, electrical, and accessibility designs are more stringent for the 9 th Street Tower and include: Fire Safety: Fire extinguishers, fire rated walls, automatic fire detection, and evacuation o Fire extinguishers in the residential corridors are within 23-m (75-ft.) of each dwelling unit, visible, and easily accessible [86]. o Fire rated walls are provided for all load bearing members to reduce the spread of fire and collapsing of the member. This allows transient occupants more time to evacuate the Tower, as they require more time to locate an exit and egress in the event of an emergency. o Sprinkler systems are also provided in the transient occupancy units. 13

25 o Fire detection systems have a higher safety standard; a manual fire alarm system is provided, and all public corridors have an automatic fire detection system. Smoke detectors are in each sleeping area and in every room leading to egress. Egress: In the event of a fire, timely evacuation is critical; most fire related fatalities are due to smoke inhalation [86]. Transient occupants are less familiar with the building layout and require more time to locate an exit and egress. o Dead End Distance: The location of the designated transient units within the 9 th Street Tower are not subject to a dead end distance greater than 12-m (40-ft.); the typical residential dead-end distance is 24-m (80-ft.) maximum [86]. The centrally located stairwell and elevators include fire rated walls, smoke barriers, etc. for further protection. o Exit and Egress Signs: Exit path markings are photo luminescent floor markings directing occupants to the egress path of travel in the public corridors. Clearly marked exit signs are located at every exit and every opening from a room. The corridors include direction signs to guide the egress in all transient occupancy areas. Egress diagrams are posted in each transient unit showing the egress layout of the floor. This includes the location and identification of the elevator and exit stairway. Elevators: The 9 th Street Tower has 4 passenger elevators and one service elevator. Electrical: An emergency power system is provided for exit signs, elevator interior lighting, emergency alarm systems, automatic fire detection systems, fire alarm systems, electrical fire pumps, ventilating systems, stair pressurization, and five elevators in the Tower. Accessibility: Transient occupancies in the Tower are accessible and includes: o Presence of an interior accessible route, accessible entrances, accessible parking, and wheelchair spaces. o Each residential floor level includes two transient occupancy units in perpetuity with smoke and/or carbon monoxide detectors with audible and visual features. The general transient occupant in the Tower is a millennial, those between the ages of years old, although more than 30% of the transient occupants is a professional over age 50 [88]. The life style of the transient worker includes a lot of time traveling, making it difficult to follow and maintain any kind of routine [87]. Hours of occupancy can differ from the typical occupant; 14

26 schedules with early morning starts, late arrivals home with limited cooking needs, and on-call work during the night influences the human behavior of these occupants; the egress evaluations differ from the permanent resident occupancy [87]. As a result, special attention is given to educating the transient group in the Tower regarding building emergency evacuation plans, see Appendix H. With greater accessibility to online resources, the fire protection strategy for the Tower includes a digital building emergency evacuation app for initial emergency education and emergency notifications [30, 91]. This custom, by invitation-only App, is designed specifically for the life safety of the Tower occupants and includes: A custom emergency preparedness and incident response system Procedures and interactive maps for fire, power, medical, terrorists, and other emergencies Building specific information, updated at each log in Evacuation status report-in feature Custom online training for the transient and permanent occupants to measure and record knowledge with a complete management and reporting system required to gain initial access as a tenant. Fire evacuation maps to direct the Tower occupants to the recommended assembly area. Integration of the building emergency plan information, including the critical building emergency contacts. Works directly from the 9 th Street Tower s Fire and Life Safety Plan Content is downloaded to a mobile device so access is maintained with or without connectivity to Wi-Fi or data. A secure, scalable, custom-made asset protection system is provided by the mobile app as a risk [30, management strategy for property preservation 91]. The critical building systems documentation of equipment, policies, and procedures are consolidated and filed in a digital repository [30, 91]. This system is also used as part of the Operation and Maintenance program for inspections, including a rapid and accurate response to equipment malfunctions, human error, and natural and man-made disasters, see Appendix F. 15

27 Accessibility Occupants with Mobility Impairments The Tower will be fully accessible in accordance with the ADA Accessibility Guidelines (ADAAG) [18]. The following items are considered for occupants with a mobility impairment: Main accessible entrance at the Ground Level. Minimum of one accessible means of egress from all spaces Accessible elevator at each floor (accessible means of egress) Stairway landing at each floor with a 1-hr. fire-resistance rated landing (accessible area of refuge). This accessible area of refuge is equipped with: Minimum intrusion of smoke including the pressurized stairway, A wheelchair space of m 1.22-m (30-in. 48-in.), A two-way communication system between the accessible area of refuge and FCC An ACCESSIBLE AREA OF REFUGE sign mounted at each entrance door to the stairway, Two emergency travel devices o Directions on using the two-way communication system, o Directions on how to request assistance to exit the building Firefighters One of the fire safety goals of this case study is to safeguard firefighters during the rescue operations. A Fire Command Center (FCC) located in the ground floor (L1) is responsible for the operation of elevators and safe evacuation of occupants using the Occupant Evacuation Operation (OEO) strategy. In addition, FCC controls utilities related to fire protection systems. Various active and passive fire protection system are designed to assist firefighters during the rescue operation: The doors are properly installed so that they can maintain the tenable conditions for the firefighters Stairway is pressurized to limit the smoke migration [63] Mechanical ventilation assists in smoke movement to outside of the building through a single, central duct Wall are encapsulated with multiple layers of gypsum boards, where each layer resist at least 40-minutes in a fire event [79-81] Sprinklers assist in fire suppression and/or extinguishment 16

28 Elevators are fire-safe and being used as the main evacuation strategy. This assist the firefighters in increasing the rescue operation time Fire-resistive doors provide protection between ¾-hr. to 1.5-hr. in the Tower, and consequently a proper baseline safety is provided for firefighters Adhesives selected for CLT wall and ceiling assemblies do not produce toxic combustion products. In addition, adhesives must withstand higher temperatures and should not contribute to fire re-growth [79-80] Engineered Structural Wood Components The Tower incorporates a wood-concrete skyscraper concept [19], using CLT and glulam mass timber members. CLT consists of crosswise layers of timber boards bonded together using a polymer adhesive [20], as shown in Figure 2.1. The resulting alternate grain direction gives CLT strength and stiffness, in terms of load bearing capacity, in two directions, increases shear capacity in the plane of the elements, and eliminates shrinkage and swelling in the plane because of humidity variations [19]. Figure 2.1 Crosswise Layers of Timber Boards [20] Glulam is an engineered composite product composed of several layers of dimensioned lumber, or wood laminations, bonded together with a moisture-resistant adhesive. The grain of the laminations runs parallel with the length of the member. By laminating several smaller pieces of lumber, a single large, stronger, structural member is manufactured. These structural mass timber members are used as vertical columns and horizontal beams in the Tower, see Figure

29 Figure 2.2. Example of a Glulam Beam [22] Mass timber has numerous advantages compared to other types of typical construction materials such as steel and concrete [20, 23]. A summary of these advantages is shown in Table 2.1. Table 2.1 Advantages of Using Mass Timber as a Construction Material Material Advantages Prefabricated (increased speed and quality) Dimensionally Stable Durability and Strength System Advantages Speed Reduced Labor Interior Environment Fire Performance Weight Sustainability Cost These benefits describe the current trend of using timber in structures [82]. Based on 2015 International Building Code (IBC) regulations and limitations, engineered wood products such as CLT and Glue Laminated Timber (Glulam) are common materials in low-rise to mid-rise timber constructions. Two distinct framing methods are used for these types of buildings, including balloon and platform framing, see Figure 2.3 below. 18

30 Figure 2.3 Platform vs. Balloon Framing [24] Mass timber construction using CLT panels and platform framing is suitable for low rise to midrise structures. However, accumulative shrinkage in tall, mass timber, platform-based structures becomes substantial and therefore, platform framing is not a suitable choice in high-rise buildings. As such, balloon framing glulam columns and beams, with CLT for walls and floors, is chosen as the proper construction method for the 9 th Street high-rise building. Connections of wall, ceiling, and roof elements have a significant influence on fire behavior, the danger being uncontrolled spread of smoke, hot gases, and fire. Poorly designed connections affect evacuation, life safety, and property preservation. As a result, concealed slots with doweled steelto-timber connections are designed to connect the glulam beams to columns and to CLT walls [19] ; embedded connections demonstrate better fire performance than fasteners and plate connections [25], shown in Figure

31 Figure 2.4 Typical Mechanical Concealed Connection [26] Charring Rate of CLT Panels When timber is heated to temperatures exceeding 200 C, pyrolysis occurs; a layer of carbonaceous char is then formed at the fire-exposed surfaces [20]. Charring occurs at a predictable rate and is easily modeled. This char layer is of low effective thermal conductivity and acts as natural insulation for the underlying timber, reducing the rate of charring and insulating the core of the timber element [20]. Beneath the char layer exists an uncharred but heated drying and pyrolysis zone [20], see Figure 2.5. Therefore, to determine the load bearing capacity of a mass timber, a nominal charring rate during exposure to a standard fire is used to predict the depth of charred timber (reduced cross-section method) [20]. Figure 2.5 Char Layer and Pyrolysis Zone in a Timber Beam [27] 20

32 Based on the CLT charring rates provided by NDS 2015 [12], the sacrificial layer of CLT is added to the main load bearing cross sections where an exposed CLT panel is present, i.e. a 4-layer CLT used for walls in upper stories instead of a typical 3-layer. This sacrificial layer of CLT is considered in fire load calculations and fire analysis of the Tower Acoustics Acoustical considerations are particularly important in residential design due to the use of spaces; the sound transference occurs in three different directions through multifamily housing: ceiling to floor, unit to unit through a demising common wall, and unit to public space along a demising corridor wall. IBC Section 1207 [3] sets minimum standards for residential design in the form of Sound Transmission Class (STC) and Impact Insulation Class (IIC). A value of 50 for the STC is required between units both horizontally and vertically between units and public areas and between units and service areas. A value of 50 for the IIC is required for the floor or ceiling assembly between units vertically. For timber construction, a 5-Ply CLT panel approximately mm (6-in.) thick has an approximate STC rating of 39 and IIC rating of 24 according to the US CLT Handbook. This requires that additional surface treatment be provided for CLT construction which can include a concrete topping slab, i.e. gypcrete, to increase the STC and finishes such as carpet, to increase the IIC. Acoustical requirements can be met with the a CLT floor system by applying the concrete topping slab and floor finishes as would typically be expected in a residential fit-out. It is assumed that the proposed details satisfy the requirements and no additional considerations are required Moisture Protection Care must be taken at areas susceptible to moisture such as kitchens and bathrooms to avoid exposing the timber to moisture long term. Events such as large amounts of water discharged from the sprinkler systems must also be considered. Therefore, the CLT on the ceilings in 9 th Street Tower are not exposed. The concrete topping on the floor slabs have a top surface treatment and provides some additional protections against moisture and acoustics Exterior Walls Exterior walls are designed to provide protection from both air and water infiltration. They also insulate the building to minimize the heating and cooling loads which can vary significantly based 21

33 on the location, context, building type, building systems and material availability. It is important therefore that the main structural system be designed to allow for flexibility in exterior wall types to ensure that no system limitations exist. Keeping the attachment method back to the base building structure as conventional as possible is therefore very important. This will help minimize the potential for any additional connection costs to be added by the contractor responsible for the exterior wall system. In addition, the interface between the exterior wall and the floor slab is critical as it should be designed to be flexible to allow for building movement and tolerance but must also be continuous and sealed to restrict the passage of fire and smoke from floor to floor. There are many tested systems for the fire and smoke stop systems, by providing a concrete slab edge condition, the edge is very similar to a conventional steel and composite deck or reinforced concrete building. 2.5 Quality Assurance During Construction Quality assurance is essential during construction to ensure life safety in perpetuity of the Tower. The tall wood frame construction consists of a combination of several different materials, which are designed and installed to fulfil multiple performance functions. The methods used for assembly/erecting these multiple layers are vital to ensuring adequate fire performance [28]. As an example, empty voids can lead to premature exposure of wooden elements in the event of a fire and can lead to earlier charring, and therefore, decreased fire resistance [28]. The quality of workmanship of such details are to be closely monitored by a third-party. The responsibilities of interacting trades must be clearly started, and project management process communicated and enforced at the beginning of the construction process. 3. ENVIRONMENTAL CONSIDERATIONS FOR SUSTAINABILITY The Tower incorporates a green (sustainable) design; the practice of creating structures and applying processes that are environmentally responsible and resource-efficient throughout the building s life cycle [21]. The Leadership in Energy and Environmental Design (LEED) 2009 Green Building Rating System for New Construction is used to evaluate the environmental performance from a whole building perspective of the Tower. This rating system is a set of performance standards for certifying the design and construction of commercial or institutional buildings and high-rise residential buildings of all sizes [21]. More importantly, LEED encourages an integrated 22

34 approach to design and construction; improving building performance, reducing risk, and achieving synergies that yield economic, environmental, and human benefits [31]. 3.1 Environmental Goal The goal for this green building project is to have an integrated process for design to reduce the overall impact of the building and development on the occupants health and environment [31] by delivering: Lower operating costs and increase asset value, Reduce waste sent to landfills, Energy and water conservation, More healthful and productive environments for building occupants, Qualifications for tax rebates, zoning allowances, and other incentives in many cities. Design prerequisites and credits are used to address these impacts, organized into seven categories, and most categories are utilized in the Tower design, including: sustainable site development, water savings, energy efficiency, materials and resources, indoor environmental quality, and innovation in design [21]. Figure 3.1 LEED 2009 Checklist for the 9 th Street CLT Tower 23

35 LEED points are awarded on a 100-point scale with four levels of certification: Certified: Points; Silver: Points; Gold: Points; Platinum: Points [21]. The owner has requested recognition as a Gold Certified Building. The LEED 2009 Project Checklist reflects the Tower s credits, shown in Figure Point Allocation Based on LEED 2009 The allocation of points is based on the potential environmental impacts and human benefits of each credit with respect to a set of impact categories [21]. The allocation of points, however, does not explicitly consider the fire risks and hazards associated with green buildings and building elements [32]. The sustainable intent for the Tower design is therefore be integrated into the fire safety strategy, complementing the building services strategy and functionality of the building. A description outlining the impact categories and associated credits allocated for the Tower is provided in Appendix C. Each impact category for the Tower can present a fire hazard while considering a performance-based design, including the following credits Sustainable Site Development Credit 2 Development Density Credit 4.3 Alternative Transportation-Low-Emitting and Fuel-Efficient Vehicles Credit 5.2 Site Development Maximum Open Space Credit 6.1 Stormwater Design Quality Control Credit 6.2 Stormwater Design Quality Control Credit 7.1 Heat Island Effect Non-Roof Credit 7.2 Heat Island Effect Roof Water Savings Credit 1 Water Efficient Landscaping Credit 3 Water Use Reduction Energy Efficiency Prereq. 2 Minimum Energy Performance Prereq. 3 Fundamental Refrigerant Management Credit 1 Optimize Energy Performance Credit 2 On-Sire Renewable Energy Credit 4 Enhanced Refrigerant Management Material and Resources Prereq. 1 Storage and Collection of Recyclables Credit 2 Construction Waste Management Credit 6 Rapidly Renewable Materials 24

36 3.2.5 Indoor Environmental Quality Credit 8.1 Credit Green Building Elements Daylight and Views Daylight Daylight and Views - Views The following green building elements are featured on the 9 th Street Tower, with potential fire and life safety concerns: Sustainable Site Concerns Increased building density: separation distance 2 meters from adjacent property lines Electric vehicle charging station Battery storage system Open Space vegetative roof system Stormwater design promote infiltration through vegetative roof system; reuse stormwater Heat Island Effect vegetative roof system; solar panels to offset non-renewable energy source Water Savings Concerns Water efficient landscaping use of captured rainwater and recycled wastewater Reduced water supply Energy Efficiency Concerns Optimize energy performance - includes several architectural features: Continuous exterior rigid foam insulation High performance glazing Area of combustible façade material Higher insulation values Vestibules Solar shading from perimeter balconies Fundamental refrigerate management use suppression system that does not contain HCFC s or halons Onsite renewable energy PV solar power energy roof panels Materials and Resources Concerns Storage and collection of recyclables trash/recycle chutes on each floor connected to a central basement location Construction waste management see Fire and Life Safety during Building Construction, Appendix H Rapidly renewable materials - engineered structural wood elements and connections (CLT) Exposed CLT interior wall feature 25

37 3.3.5 Indoor Environmental Quality Concerns Daylight and Views includes several architectural features: Low-emissivity and reflective coating Open floor plans (horizontal open compartment) Large areas of glazing on exterior walls, see Appendix D for Daylight requirements Glass interior walls, see Appendix D for Views requirements 3.4 Carbon Footprint of Wood Structures Today, the focus on the carbon footprint of buildings has increased around the world and architects effort is to decrease the atmosphere s greenhouse gases by designing and constructing high performance buildings. Carbon footprint is the amount of the volume of CO2 emitted into the atmosphere to produce and use a material. The footprint concept makes it possible to measure the impact of different materials on the environment. Buildings account for a significant portion of greenhouse gas emissions; in the U.S. buildings are associated with 39% of all emission of CO2; globally, the figure is nearly 1/3 [31]. However, timber is nearly carbon neutral, the only building material with a negative CO2 balance, i.e. it stores CO2 [19]. Each cubic meter of wood sequestrates an average of 0.8 to 0.9-tons of CO2 [25]. With the footprint dimensions for this case study, the Tower uses approximately 0.2m³ of CLT panel per m 2 of apartment unit. This high-rise is a 32-story residential building with a footprint of 40m x 40m; CLT wood panels are the main construction material to erect 27 floor levels. As a result, a total of approximately 8640m³ of CLT wood is required for the floors, eliminating approximately 7,344-tons of CO2 emissions from other potential building materials. This is equivalent to the CO2 emissions of 4,848 cars in one year [25]. Building with wood, rather than other typical construction materials help to reduce greenhouse gases released into the environment, thereby reducing the carbon footprint, see Figure 3.2 below. 26

38 Figure 3.2 CO 2 Emissions of Typical Construction Materials over Full Life-Cycle [34] In addition to current concerns about the amount of greenhouse gases emitted to the environment, one other important consideration is the energy efficiency and carbon footprint of the buildings. According to the previous studies, wood has the smallest carbon footprint among construction materials [10, 11]. Environmental experts believe that wood is a carbon negative material [25]. During the production of wood and in the very first steps, wood improves the environmental condition through absorbing carbon dioxide. Steel and concrete are the other construction materials that leave a very large foot print. In comparison to these materials wood has a small carbon footprint. Using the wood as a construction material will reduce the carbon footprint of the building by carbon storage and avoiding greenhouse gas emissions. When a tree is growing, the photosynthesis process helps the tree to absorb the CO2. Then, the tree will store the carbon and release the oxygen. By forest management, trees will be harvested before they rot and release the carbon to the atmosphere. By using wood as structural material, the carbon will be kept out of the atmosphere for the lifetime of the construction. Using wood instead of steel and concrete will reduce the carbon emission up to 50%. The wood structures act similar to the secondary forest by storing tons of carbon dioxide. 3.5 Impact of Wood Use on Forests Wood is a renewable resource, providing the forests being harvested are sustainably managed, as seen in the Southeast United States forestry practices [90]. By sustainably managing a forest, trees are harvested, and the area is replanted to replenish the source [90]. This ensures not too many trees are harvested at once, causing resource depletion [90]. There are two certification standards in the 27

39 United States that recognize sustainably managed forests for meeting their specified criteria; the Tower incorporates the Forest Stewardship Council (FSC). It is the only type of wood recognized in LEED ratings; the forest, chain-of-custody, and sourcing requires a third-party audit to achieve certification. The programs work to ensure forests continue to contribute to their additional environmental benefits [90]. Almost 30 percent of the earth is covered by forests, see Figure 3.3 below. Only 5% of these forests is in the European Union. European forests are mainly used for wood products and, by considering the increase in the demand for these products, it seems that they are endanger. However, recent studies confirm the European forest area increased 7% during last 25 years. This happened by reforestation and forest management methods in this area [35]. The US and Canada together have 15% of the world s total forest cover and both countries have almost the same amount of forested land today as they had 100 years ago. It is due to forest management and sustainability, as they are prerequisite for landowners to ensure a positive return on investment. Figure 3.3 Forest Distribution across the Globe [35] During the past 50 years, approximately 2% of the trees in the US has been harvested, while net tree growth in the US was 3%. In Canada, strict sustainability laws and regulations resulted in managed harvesting and regenerating the trees. Therefore, by proper forest management laws and regulations harvesting trees did not affect the environment of these countries [36]. 4. FIRE SAFETY GOALS, OBJECTIVES, AND PERFORMANCE CRITERIA 4.1 Fire Safety Goals Among the four general fire safety goals for a property during a fire incident, the primary fire safety goal of this project is to provide life safety to the public, building occupant, and fire fighters 28

40 during an emergency. Other fire safety goals include property preservation, continuity of operation, and decreased environmental impacts. 4.2 Fire Safety Objectives The stakeholders for the case study developed the following 4 fire safety objectives: Protecting occupants (transient, permanent, and staff) against fire incidents Protecting firefighters while fire suppression and rescue operation Maintaining the structure s integrity in a fire event Preventing fire spread to adjacent buildings in a fire event 4.3 Performance Group Based on Section 303 of the 2015 International Code Council Performance Code (ICCPC) [37], Performance Group III is allocated for the CLT tower Maximum Level of Damage to be Tolerated Based on Section 304 and Table of the ICCPC [37], level of impact regarding the magnitude of events for the Performance Group III varies between mild to high. The Tower is designed in such a way that there is a low probability of fire spread to the upper floors and a low probability of structural collapse at any time during a fire regardless of if the fire can be controlled by the firefighting services and/or suppression system. The possible impacts are summarized in Table

41 Magnitude of Design Event (Increasing) Table 4.1 Maximum Level of Damage to be Tolerated, Design Event Magnitudes, and Impacts for Performance Group III Performance Group III Level of Impact Impact Details Impact/ Hazard Type Very Large (Very Rare) Large (Rare) Medium (Less Frequent) Small (Frequent) High Moderate Mild Significant, yet no large falling debris Repair is possible Significant delay in re-occupancy Significant damage, inoperable Light debris in egress routes Significant damage to emergency systems, yet operational Locally significant with high risk to life, yet generally moderate in numbers and in nature Moderate likelihood of single life loss vs. low probability of multiple life loss Higher expected level of injuries in fire hazards in localized areas Locally total and generally significant Higher expected level of injuries in fire hazards in localized areas Release to environment Immediate need for localized relocation for building and facilities Repairable damage, some delay in re-occupancy Fully operational, minor cleanup and repair Emergency systems are fully operational Locally significant, but generally moderate in number and nature Higher expected level of injuries in fire hazards in localized areas Locally significant, generally moderate in extent and cost Higher expected level of injuries in fire hazards in localized areas Some release to environment, minimal risk to community No need for emergency relocation Property is safe to occupy Fully operational Minimal in number and minor in nature Low likelihood of single/multiple life loss Higher expected level of injuries in fire hazards in localized areas Minimal in extent and minor in cost Minimal amount release to environment Structural Damage Non-Structural Systems Occupant Hazards Overall Extent of Damage Hazardous Materials Structural Damage Non-Structural Systems Occupant Hazards Overall Extent of Damage Hazardous Materials Structural Damage Non-Structural Systems Occupant Hazards Overall Extent of Damage Hazardous Materials 30

42 4.3.2 Risk Factors and Risk Assessment Risk Factors Based on occupancy classifications in the CLT tower (summarized in Table 1.1) and ICCPC 2015 [37], the following considerations are applied to risk assessment: fire hazards, length of occupancy, sleeping characteristics, familiarity, and vulnerability Fire Hazard and Hazard Assessment of the Green Building Initiatives The performance-based design for fire protection and life safety of the Tower contributes to the sustainability of the project. Prevention of fire is a significant green design feature [38]. The environmental impact of a fire with the release of carbon gasses, destruction of resources, and runoff of suppression products can have a greater negative impact than the actual savings in the building design [38]. Figure 4.1 Contribution of Risk Factors to Total Lifecycle Carbon Emissions [39] Without an effective performance- based design for the fire protection, the risk of fire increases the carbon emissions over the lifecycle of a building and can add up to 14% to the carbon emissions over the lifetime of a facility exposed to extensive fire hazard [41], see Figure 4.1. Identifying fire hazards and providing mitigation strategies for green building initiatives uses a comprehensive approach to provide an exemplary performance. Therefore, the Innovation in Design ID Credit 1 provides an avenue for environmental performance using a fire protection strategy not specifically addressed in the LEED Green Building Rating System. The sustainable intent for the Tower design is integrated into the fire and life safety protection strategy. Without mitigating strategies, the fire hazards from green building initiatives can 31

43 increase, life safety can decrease, and/or building performance in comparison with conventional construction can decrease [32]. A quantification method to compare the relative fire performance of green materials and the risk associated with them is currently being researched [32] ; existing quantitative or semi-quantitative fire hazard assessment methodologies available on the market today are unlikely to be suitably weighted for a façade fire scenario [41]. Therefore, a semiquantitative fire hazard assessment is developed, assigning values to selected variables, based on professional judgment and past experience [83]. The following variables (attributes) associated with the fire hazards of the above listed green building credits are identified as performance concerns for the Tower and the facade, impacting fire, life safety, building and/or fire service performance [32] : Potential source for ignition, shock, explosion, or toxicity hazard Potential source of fuel (readily ignitable/burns readily once ignited) Potential source of oxygen Affects burning characteristics Significant smoke production/hazard Presents flame spread concern May impact smoke/heat venting May impact suppression effectiveness/fire fighter water availability May impact fire apparatus or fire fighter access The semi-quantitative approach uses a widely recognized index method, establishing an order of magnitude [84], with relative rankings based on professional judgement and experience [9]. Levels of impact are assigned; relative hazard levels are estimated, as a weighted function of the importance or influence, of the hazard impact on the various green elements [32] ; decision-making tables and matrices are developed; and the overall hazard ranking of the Tower with the designed green building initiatives is calculated. The methodology and structure of the semi-quantitative approach is described briefly in Appendix B. Based on the technique developed to quantify and evaluate the fire hazards of the green building initiatives on the Tower outlined in Appendix B, a Moderate Impact Level (marginal adverse impact to life safety and property preservation) is imposed on the Tower. However, the impact by the fire initiation or fire growth within the assemblies created by these green material components 32

44 on the Tower can result in enhanced heat release rates and pathways of fire spread not typically observed with standard construction materials [82] ; a synergistic effect is created by the combination of the components and can be greater than the sum of its parts. As a result, there can be an increase in the level of hazards and concern for the Tower; the magnitude of a fire event can be affected. Therefore, mitigation strategies are implemented in the project design based on the synergy of the elements to reduce the fire hazards associated with the green building initiatives Mitigation Strategies The same semi-quantitative approach, as used above, then analyzes the impacts after mitigation, reassigning numerical values for the hazard ranking matrix, based on engineering judgement and experience. The relative hazard level is recalculated; decision-making tables and matrices are redeveloped; and the overall hazard ranking of the Tower with the mitigated measures is calculated. The approach is described briefly in Appendix B. Based on the technique developed to quantify and evaluate the fire hazards of the mitigated measures, or trial design option [89], for the designed green building initiatives on the Tower outlined in Appendix B, a Mild Impact Level (minimal adverse impact to life safety and property preservation) is imposed on the Tower. The greatest individual reductions occur in the façade elements in the Energy Efficiency Category, including the continuous insulation, area of combustible façade material, higher insulation values, and large areas of glazing. The synergistic effect of these green building façade initiatives is considered during the mitigation analysis and reflected as impact reductions. To evaluate the technique developed for this case study, a verification process is undertaken. A comparison fire risk assessment is performed and provided in Appendix B. Alternate fire risk assessment comparisons continue for validation and sensitivity analysis, helping to bridge the gap towards quantification of the fire hazards of green building initiatives in the built environment. The potential for fire spread and fire growth to multiple stories of the Tower through the façade system is reduced by implementing several integrated features. Consequently, sustainability measures for the Tower can be implemented, providing measures are taken to responsibly offset the potential fire hazards associated with the green building initiatives. The fire safety strategy in the performance-based design for the Tower integrates the sustainable intent for the life safety of the building occupants and firefighter, property preservation, continuity of operations, and the environmental impact. 33

45 5. PRESCRIPTIVE CODES The prescriptive analysis for the building is based upon the International Building Code (IBC) 2015 [3]. The City of Charlotte 2012 Code includes the provisions for the development of the Tower in the Charlotte Uptown Mixed- Use District (UMUD). The Tower is designed as a mixed-use structure, including the following occupancy classifications: Assembly (A1-theaters and A3- gymnasium/community halls), Business (B), Mercantile (M), Storage (S2-parking garage open or closed), and Residential (R1-transient and R2-apartment houses). The allowable height and number of stories above grade plane are unlimited as the building will be equipped with an automatic sprinkler system, per Tables and [3], respectively. The base construction is Type IV, fire-resistive noncombustible construction, except as permitted elsewhere in the code. The fire-resistance rating requirements for the exterior walls of the building, based on the separation distance of 2-m (6-6 ), is 1-hr., except for a 2-hr. rating at the Mercantile occupancy area. Special provisions allow CLT within exterior wall assemblies with a 2-hr. rating or less, provided the members are protected with a minimum of 11.9-mm (15/32-in.) fire-retardant sheathing, a minimum of 12.7-mm (½-in.) gypsum board, or a noncombustible material. The use of combustible materials, such as thermal insulation, plastics, and exterior wall covering, are permitted on the Tower in accordance with Sections through [3] and are investigated for use in this case study. Areas of refuge are not required since the Tower is equipped with automatic sprinkler system. Sprinklers are required on residential balconies and decks where there is a combustible deck or roof above per IBC [3]. The Tower incorporates several innovative materials and systems into the building design; prescriptive measures for compliance are not provided in the IBC. To compensate for this, the IBC includes an alternate materials and methods clause in section [3] ; an alternate design solution is provided for the Tower to meet the intent of the code and is equivalent in terms of safety and related parameters [85]. This case study includes a performance-based design to address this issue. 34

46 6.1 Methodology 6. PERFORMANCE-BASED DESIGN AND ANALYSIS There are different approaches to achieve requirements of a performance-based design. Deterministic methods, including defining different scenarios, is one of these strategies. In this case study, evaluations are based on providing a specific level of fire performance and consideration for the code-specified levels of fire-resistance [69, 72, 73]. To achieve the fire safety goals and objectives of this case study, 4 design fire scenarios, egress analysis, a semi-quantitative fire hazard assessment, and 4 trial designs are evaluated. To examine each performance criteria, computer models are used to simulate fire and smoke behavior, and evacuation time. The outline to evaluate the performance-based design for this case study is obtained from the SFPE Engineering Guide to Performance-Based Fire Protection [17]. Fire models are performed using Fire Dynamic Simulator (FDS) and PyroSim. The following properties are evaluated during the fire simulation using FDS: Sprinkler and detector functionality Gas layer temperature Heat release rate Heat flux Natural and mechanical ventilation Smoke obscuration The latest Fire Dynamics Simulator User s Guide [43] (V.6.6), the SFPE s Guidelines for Substantiating a Fire Model for a Given Application [44], the SFPE Engineering Standard on Calculating Fire Exposure to Structures [45], and the SFPE s Engineering Guide: Fire Safety for Very Tall Buildings [46] was used for fire modeling assistance. Egress simulation is performed for each fire scenario using Elevator Evacuation (ELVAC) and SIMULEX. The performance-based design for the Tower addresses the following building features: Tall building with a structural timber system Exposed timber features Transient occupants Occupant evacuation elevators Sustainable design The elevator evacuation modeling and analysis was performed using the SFPE s Engineering Guide: Human Behavior in Fire [47], Egress Design Solutions- A Guide to Evacuation and Crowd 35

47 Management Planning [48], SFPE Handbook of Fire Protection Engineering [49], and NFPA Handbook of Fire Protection [50]. 6.2 Building Characteristics The full list of building characteristics is provided in Appendix E. 6.3 The CLT Tower s Tenability Criteria The performance group, and maximum damage to be tolerated, were outlined in section 4.3. To evaluate the occupants response to a fire event, the following tenability criteria is selected and summarized in Table 6.1 [49, 51-53]. Radiant Flux Parameter Convective Exposure (Elevated Air Temperature) Convective Exposure (Elevated Smoke Temperature) Table 6.1 Tenability Criteria Description Max. 2.5-kW/m 2 (793-Btu/ft. 2 /hr.) at Head Height (1.8-m or 5.9-ft.) 60 ºC (140 ºF) for 30-Minutes Exposure to Air Saturated with Water Vapor 60 ºC (140 ºF) for 30-Minutes Exposure Visibility Distance Smoke Toxicity (CO Concentration) Smoke Toxicity (Hydrogen Cyanide) Max. 10-m (33-ft.) to Doors and Walls Max. 1,500-ppm for the First 6-Minutes of Exposure Average of 1000-ppm for the First 20-Minutes of Exposure Max. 100-ppm for the 20-Minutes of Exposure A heat flux of 2.5-kW/m 2 is considered the maximum tolerable to naked skin. Any radiant heat exposure above this value could not be tolerated more than 20-s [51]. Exposure to the combustion toxic gases may cause incapacitation, and longer exposure time may also lead to death. The oxygen concentration in a room should not drop under 8%, otherwise it would be fatal in 8-minutes [55]. Any concentration of O2 below 15% causes hypoxia, leading to a decrease in physical capability [54]. Smoke obscuration may reduce the occupants movement during a fire event, and consequently an increased exposure time to radiant heat flux, elevated temperature, and toxic gases. NFPA 130: Standard for Fixed Guideway Transit and Passenger Rail Systems, recommends a 10-m (33-ft.) visibility to doors and walls [53], while Purser recommends 5-m visibility for small and 10-m for large enclosure and distances [49]. 36

48 Hydrogen Cyanide (HCN) is also considered one of the combustion s toxic gases in which the exposure could rapidly leads to incapacitation. The Fractional Effective Dose (FED) method provides more details on calculating the toxic gases threshold. A comparison diagram for CO and HCN is illustrated in Figure 6.1 [49] Figure 6.1 Time to Incapacitation during Exposure to HCN and CO 6.4 Occupant Characteristics The occupant load for the residential building is summarized in Table 6.2. Personal care services will be provided to the residents on three different floors; L9, L17, and L25. It is expected the residents of the building are capable of self-preservation. Since the CLT tower is a condominium apartment building for a gig economy, the building hosts transient occupants. Therefore, most of the building population will not be familiar with the building s layout and it will be imperative to familiarize new residents with the Fire Emergency Plan, including the use of occupant evacuation elevators, refuge floors and areas, and fire extinguishers, see Appendix G. Risk factors for occupants such as occupancy length (especially for transient occupants), familiarity, and impairment are considered in the performance-based design approach. 37

49 6.5 Egress Analysis A comprehensive egress analysis was conducted to determine the required exit capacity and minimum travel distance required to reach the exits. Since the evacuation strategy is based on selfevacuation using elevators, egress modeling is performed using ELVAC to calculate the total egress time. Note, this software does not show the results for those occupants who do not use elevators for evacuation [48]. Consequently, egress calculations were performed for parking levels (P1 and P2), and the Sky Deck; occupants in these levels use stairway as the mean of egress. Calculations are compliant with the SFPE Engineering Guide: Human Behavior in Fire Areas of Refuge Floors levels 9, 17, and 25 are each equipped with areas of refuge; enclosed in 2-hr. rated smoke barriers, and equipped with two-way communication system to the FCC, evacuation chairs, lavatory, and openings protected with water curtains. Each of these three floors has 4 dedicated, 5.5-m 9-m (18-ft ft.) spaces for areas of refuge. Floors are constructed from non-combustible precast concrete with a 2-hr fire resistance rating. Walls are constructed from 4-ply CLT (considering one sacrificial layer) with complete encapsulation by 3 layers of type X gypsum board, each 15.9-mm (5/8-in.) of thickness, to provide 3-hr. fire rating on all sides of the CLT member. Areas of refuge are directly accessible from the elevator lobby, also located in the 3-hr. fire rating concrete core of the CLT Tower. As mentioned in section , stairway landings at each floor are also considered as an area of refuge. These landings are 1-hr. fire-resistance rated and equipped with a wheelchair space of m 1.22-m (30-in. 48-in.), two-way communication system between the accessible area of refuge and FCC, and two emergency travel devices in the accessible area of refuge (stairway landing) Occupant Load The calculations in this section are used to compare the results from the elevator evacuation strategy. Occupant load is calculated using the NFPA 101: Life Safety Code (2018 Edition) and summarized in Table 6.2 [10]. 38

50 Floor Number Table 6.2 Occupant Load Number of Occupants per Floor L1 327 L9 L17 L25 All Residential Floors Except L1, L9, L17, and L25 P1 P2 Sky Deck 847 a 797 a 735 a c 66 c 50 b a Based on the areas of refuge, and different occupant load factor for each section b The capacity is limited to 50 people c Based on maximum floor area allowances per occupant in IBC 2015 Floors L9, L17, and L25 are the refuge floors, where the occupant load in areas less than 930-m 2 (10,000-ft 2 ) in limited to 0.46-m 2 (5-ft 2 ) [10]. Each retail area on the ground floor (mall area) has an exit, in addition to the main entrance on the west side of the building. All floors have access to a stairway and 4 passenger elevator cars Elevator Evacuation Design Elevators provide a safe and quick mean of egress when properly designed. Studies showed that traveling time of firefighters could be decreased between 15 to 30-min. in case they are able to use elevators in a fire incident [67]. Elevators should be capable of moving 10% of the total occupants in modern high-rise buildings within 5-minutes during the peak time [66]. The evacuation time should be designed to meet the fire safety goals of the CLT tower. Elevator evacuation methodology follows the steps illustrated in Figure 6.1 [48]. 39

51 Elevator receives the alarm signal Elevator(s) travel to the designated discharge floor Elevator(s) continue the round-trips to evacuate all the occupants from those 5 levels Elevator(s) travel to the event floor and two lower and higher levels Figure 6.2 Elevator Evacuation Steps An evacuation strategy based on elevators as primary means of egress could be complicated and contains uncertainties. For instance, it is difficult to predict the exact location or operability of the elevator(s) as an incident occurs. In addition, number of occupants in each floor is constantly changing regarding the nature of the CLT Tower s use as part of the gig economy. As a result, the Tower design has incorporated specific elevator design features including; an additional elevator to reduce waiting times and increase transport time; the use of high-speed elevators to reduce waiting time and increase transport time; oversized elevator lobbies designed to accommodate 100% of the anticipated population on every floor at m 2 (3-ft 2 ) per occupant, with an additional 25% area for the disabled and wheelchairs; and elevator lobby is adjacent to a redundant exit stairway in the concrete core. The following parameters should be considered to calculate the elevator evacuation time: Startup time, round-trip time, standing time, and travel time. These parameters should be used in the following equations [48] : t T = t ST + t OE + [ t R k E n E ] Equation (1) t ST = t FD + ((t E + t D ) k TE ) Equation (2) Where: t RT = t ED + t S Equation (3) t S = (t PI + t PO + t D ) k TE Equation (4) k ET = k T + 1 Equation (5) k T = k BT + k D + k O Equation (6) t T t ST t OE Total Evacuation Time [s] Start-Up Time [s] Occupant Travel Time to Exit [s] 40

52 t R k E t FD t E t D k TE t RT t ED t S t PI t PO k TE k T k BT k D k O Required Round-Trip Time [s] Efficiency Factor Travel Time from Farthest Floor to Discharge Floor [s] Time for Passengers to Exit Elevator [s] Time for Doors to Open and Close [s] Transfer Efficiency Factor Round-Trip Time [s] Travel Time to Evacuation Floor and Back to Discharge Floor [s] Standing Time [s] Time for People to Enter Elevator [s] Time for Passengers to Exit Elevator [s] Transfer Efficiency Factor Total Transfer Efficiency Basic Transfer Efficiency Door Inefficiency Factor Other Inefficiencies Evacuation Strategies Using elevators as primary means of egress has both benefits and concerns, where decades of public perception of not using elevators in case of a fire brings anxiety and fear to the occupants. Waiting time, capacity limitation, need for a backup plan, special design of the elevator, and need for assistance to operate the elevator are some of the other concerns while using elevators as an evacuation method [56]. On the other hand, it is beneficial for those occupants with mobility impairment since they could keep their mobility device. Evacuation could be performed both vertically (relocation to refuge floors or exit discharge) or horizontally (relocation of occupants with mobility impairments to the areas of refuge located in the stairway connection to the floors). Authors considered various evacuation strategies based on incident types. Elevator lobbies on each floor are equipped with real-time displays showing elevators information such as estimated arrival time, availability, remained capacity, and operability for each elevator. This assists the occupants to decide on an alternative evacuation method (stairway), relocation to area of refuge in the stairway landings, or ascend/descend to the closest refuge floor using stairs. In addition, real-time voice commands and/or announcements and visual signal notifications to 41

53 elevator lobbies and cars assist the occupants to choose the best route and/or evacuation strategy. Per section 7.9 in NFPA 101 and section 1008 in IBC 2015 [3, 10], emergency lighting is provided for all of the emergency exits and pathways. This include a minimum of 1.5-hr. of emergency illumination case of a failure of the normal lighting system; providing an average of 10.8-lux (1 ft.-candle) along the egress path Relocation using Egress Elevators and Defend-in-Place Relocation and defend-in-place are two common evacuation strategies used in high-rise buildings. In case of a fire event, occupants of the event floor, in addition to two floors above and two flors below the event floor, should be evacuated to a lower floor and/or discharge level. Egress elevators are used as the primary mean of egress in the CLT tower. Occupant Evacuation Operation (OEO) integrates fire alarm systems and egress elevators during a fire event to ensure safe evacuation of all occupants. Priority of landing for elevator(s) is given to floors with an active alarm. The OEO strategy is compliant with requirements in ASME , NFPA , NFPA 101, and IBC 2015, some as follow [3, 10, 15, 57-60] : Pressurized hoist way, stairway, and elevator lobby 2-hr. protected emergency power to elevators, signage/ voice systems, ventilation, and pressurization systems Automatic sprinkler system Smoke detection system Water flow protection for hoist ways Voice alarm/ communication system Two groups of elevators are designed for the CLT tower: E1 and E2; each include 2 elevator passenger cars. During a fire event on a floor, OEO systems enable the elevators to work with fire protection systems and move occupants to the nearest, lower refuge floor. Note, the OEO system is designed to work for levels L1 to L30; occupants in the parking levels and floors L1 to L8 will use the stairway as a mean of egress. In addition, occupants on the Sky Deck use the stairway to descend to L30 to use the elevators. In order to perform OEO, the CLT tower is divided into 6 zones, illustrated in Figure 5.1. Zones and discharge levels are summarized in Table

54 Table 6.3 Zones and Exit Discharge Levels Discharge Level Zone Evacuation Strategy OEO Total 1 (L2-L8) L1 Exit Discharge Floor 2 (L10-L16) L9 3 (L18-L24) L17 L1 4 (L26-L30) L25 5 (P2-P1) See footnote a 6 (Sky Deck) See footnote b a Assuming occupants in the parking use stairs to evacuate to L1 b Assuming occupants on the sky deck use stairs to evacuate to L30, and then descend to L25 using elevators for phased evacuation, and descend to L1 for total evacuation Total Building Evacuation Total evacuation is normally event-based, where conditions determine the best strategy. Regarding the uncertainties of human behavior during an incident, it is recommended to consider a safety factor of 2 during an evacuation modeling [49, 66]. A total building evacuation could be initiated in extreme events such as natural hazards (e.g. hurricane or other extreme weather conditions) and man-made hazards (e.g. a bomb threat). Elevators will land on all floors, with priority to the farthest ones from the discharge level (L30). Parking levels are excluded from the elevator-based evacuation in the total evacuation strategy. Occupants in levels P1 and P2 are to use stairway as a mean of egress (to the discharge level, L1). Additionally, occupants on the Sky Deck descend through the stairway to L30 to use elevators, and discharge in the ground floor. 43

55 (a) Zone Evacuation (b) Total Evacuation Figure 6.3 Evacuation Strategies in the CLT Tower Egress Calculations Occupants in parking levels and on the sky deck should use the stairs to ascend/ descend to another floor to use the elevators for evacuation. Occupants in the remaining floors (except the ground floor) are assumed to use the elevators as the primary mean of egress Pre-Movement Time Pre-movement time is defined as the initiation of an alarm to the time that occupant(s) decide to evacuate the building. Depending on numerous factors such as age, gender, familiarity, cultural background, type of occupancy, etc., the pre-movement time could be different. In total evacuation, residents of levels 2 to 5 are assumed to evacuate the building using the stairway. Since the Tower hosts transient occupants, the assumption has made that regarding the unfamiliarity, the pre-movement time is increased for such occupants. Thus, the response time in residential floors (L2-L5) is considered 300-s. NFPA 72 requires a maximum of 10-s between the alarm initiation and activation of fire protection systems (FPS). The maximum alarm initiation time in this case study is 25-s. Also, the response time for occupants in the mall, parking, and sky deck is 30-s. As a result, pre-movement times are 65-s for the Sky Deck, parking, and the mall area; 335-s for residential floors (L2-L5). It is assumed 44

56 that 2% of the occupants in levels L2-L5 have mobility impairments and use elevators as the primary mean of egress Time to Reach the Stairway The maximum distance to the stairway in residential floors is 38-m (125-ft.). For parking level, this distance is 30-m (98-ft.), and for sky deck is 33-m (108-ft.). Considering the movement velocity of 1.24-m.s -1 (244-ft.m -1 ), the time to reach the stairway, (T), is calculated as follows: TExit Door=Distance/Velocity Equation (7) TResidential= 31 s, TSky Deck=27 s, TParking=24 s Maximum Flow Time Following the hydraulic model of emergency egress in the SFPE Engineering Guide: Human Behavior in Fire, the maximum flow time is calculated as shown below: T Door= Population/ (Maximum specific flow per meter of effective width).(effective boundary layer width) Equation (8) As a result, TDoor is calculated as below; considering the maximum specific flow as 1.32 persons/m-s and effective width of 0.81-m (2.7-ft.) for the stairway s door. TDoor, Residential= 101 s TStair, Residential =83 s TDoor, Deck= 75 s TStair, Deck =61 s TDoor, Parking= 98 s TStair, Parking= 80 s The controlling component of the egress calculation is the door into the stairway. Consequently, total travel time for the occupants to enter the stair is as follow: TTotal, Residential =132 s, TTotal, Deck =102 s, TTotal, Parking= 122 s Time of Descent through the Stairway For the CLT Tower, stairway doors are 0.91-m (36-in.) wide, floor-to-floor distance of 3-m (9.8- ft.), and 1.22-m 2.44-m (4-ft. 8-ft.) landings. Stairs for this case study are a typical 178/279 (7/11) design, with stair riser of 178-mm (7-in.) and stair tread of 279-mm (11-in.). The hypotenuse of a single stair is 330-mm (130-in.). Therefore, the diagonal travel distance of one set of stairs between each floor level of the 9 th Street Tower is 5562-mm (18-ft.). Considering 1 landing at each floor, the vertical travel time is calculated as 1,425-s. 45

57 Total Evacuation Time Evacuation time considers the occupants in two parking levels in addition to occupants in levels L2 to L5. The total occupant load in these 6 stories is equal to 404. Note that the occupants in the sky deck are not considered in the final evacuation time calculation as they descend to the L30 and use the elevators, both for phased and total evacuation. Thus, the TExit is calculated as 603-s. In addition, TOutside=18-s is the time that occupants traverse the 23-m distance between the stairway s door and the exit. To sum up, the evacuation time is 2,178-s (36.3-minutes), considering the TTotal, Residential as the largest value among all. Note that this value is valid only for evacuating two parking levels and the first 5 residential floors (L1-L5) Elevator Egress Calculations As mentioned in section 6.3, a couple of equations should be used in case of egress analysis using elevators. For the CLT Tower, elevators are considered the primary means of egress, and they are used in both phased and total evacuation strategies. Hand calculations are compared to simulation results from ELVAC. The basic parameters for this calculation is summarized in Table 6.4. Table 6.4 Input Values for Elevator Evacuation Factor Value Number of Stories Served by the Elevator Group 32 Floor-to-Floor Height [m] P2-L30 3 L30-Sky Deck 2 Average Population per Floor 30 Number of Elevator Cars in Group 2 Elevator Speed [m/s] 3.56 (700-ft./s) Elevator Acceleration [m/s 2 ] 1.54 (5-ft./s 2 ) Elevator Car Capacity 25 Elevator Door Type Elevator Door Type Width [m] Single-Side, Center Opening 1.22 (4-ft.) Trip Inefficiency 0.10 ELVAC calculates the required time to evacuate a number of occupants using one group of elevators as below [65] : 46

58 All Round Trip Times Number of Elevators + Time to Start Up the Elevator Evacuation + Travel Time from Elevator Lobby to Exit (or a Safe Location) (Equation 9) Each roundtrip consists of the following sequence [65] : Elevator door closes Elevator travels to another floor Elevator door opens Occupant(s) enter the elevator Elevator door closes Elevator travels to discharge floor Elevator door opens Occupant(s) /passenger(s) leave the elevator As previously mentioned, it is assumed that only 2% of occupants in the first 5 floors and parking levels use the elevator in a fire event. This reduces the number of occupants with mobility impairment to 6 (excluding the ground floor). Also, it is assumed that an average of 25 out of 30 occupants in each floor use the elevators. Based on the fire event s floor, the FCC initiates the OEO strategy. Evacuation starts from the highest to the lowest floor. To calculate the egress time for the parking and residential floors elevators start to evacuate the residents from the L5, and continue to L4, L3, L2, P2, and finally P1. To calculate the roundtrip time, additional parameters are needed. Equation 10 shows the relationship among these parameters [65]. TTotal=N (TDoor+T Load+TTravel) (Equation 10) Regarding to ELVAC s calculations, the startup time for automatically operated elevators for total evacuation is s. It is assumed that only 2% of occupants use the elevator for both partial and total evacuation in both parking levels (P1-2) and Levels 2 to 5. Simulation results using ELVAC are summarized in Table

59 Table 6.5 Exit Discharge and Travel Time for the CLT Tower Travel Time to Discharge Level (s) Zone 1 (L2-L8) 2 (L10-L16) 3 (L18-L24) 4 (L26-L30) 5 ** (P2-P1) 6 * (Sky Deck) Partial s (11.63-min.) s (17.45-min.) s (17.45-min.) s (10.98-min.) s (3.6-min.) 102-s (1.7-min.) Evacuation Type Total s (90.47-Min) * Assuming occupants on the Sky Deck use stairs to evacuate to L30, and then L25 using elevators ** Assuming occupants in the parking levels use stairs to evacuate to L1 7. DESIGN FIRE SCENARIOS 7.1. Design Fires Based on steps defined in NFPA 1: Fire Code (2018 Version) [61], 8 typical design fire scenarios are considered and 4 are evaluated in this case study. Authors used Fire Dynamics Simulator (FDS) and PyroSim for fire and smoke simulation. Design fires are selected based on [74] the variety of hazardous situations, level of adaption to address a general safety measure, level of complexity, and dynamic nature. To address the unique features of the current residential building (such as different fire hazard due to using CLT), better understanding of structure s behavior in a fire incident, and absence of codes and standards addressing CLT as a construction material, a performance based-design approach is a better option for this building Scenario 1- Typical Occupancy-Specific Design Fire Scenario Scenario one involves a typical kitchen fire in residential spaces. The fire starts from cooking oil in a pot on a stove. The scenario explicitly addresses the occupant activities, room size, contents, fuel properties, ignition source, ventilation conditions, and the properties of first ignited item(s) [10]. 48

60 7.1.2 Scenario 2- Ultra-Fast Developing Fire in the Primary Means of Egress This scenario involves a Christmas tree fire occurring in the mall (retail) area at the first (discharge) level. The Christmas tree is surrounded by sofas, and fire propagates to them. The Christmas tree and sofas are close to the primary entrance of the CLT Tower. The entrance is assumed to be open during the incident. The effects from the fire spread, extent of smoke, and tenability is evaluated. The main concern of this design fire scenario is the reduction of available means of egress [10] Scenario 3- Fire in an Unoccupied Room near a High-Occupancy Place This scenario involves a fire in the unoccupied spaces of the amenity floors (changing rooms) adjacent to the fitness center. Fire starts from items in the changing room (e.g. towels) and propagates to other combustible materials. Many occupants on the amenity floors are potentially endangered with this fire, though the fire is controlled by sprinklers Scenario 4- Concealed Space Fire near a High-Occupancy Space This scenario involves an electric fire in the wiring area between gypsum boards and CLT wall panels in one of the rooms in residential apartments. This scenario addresses an incident absence of any suppression and/or detection fire protection system [10] Scenario 5- Slow Developing Shield Fire near a High-Occupancy Space This scenario involves a slowly developing fire resulted from a cigarette in a laundry basket in one of the washer/dryer rooms adjacent to elevator lobby on residential floors. No door is designed for this section, and the fire grows to the elevator lobby, which is considered as a high-occupancy section in a typical residential floor. The fire is then suppressed by sprinklers Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load This scenario involves a rapidly developing fire in presence of occupants in a workroom in one of the apartments, where piles of papers and books in addition to the beddings, sofa, and bookshelves produce the highest possible fuel load. Ceiling in the residential areas are exposed CLT (except for kitchens and bathrooms); consequently, the potential contribution of CLT panels to the fire load is evaluated in this scenario Scenario 7- Outside Exposure Fire This scenario involves a fire started from a grill on one of the residential apartments balconies. Fire propagates to exterior walls of the patio (façade). No fire protection system is designed for 49

61 the balconies, and walls are encapsulated with at least one layer of type X gypsum board. The balcony s door is assumed to be opened at a certain time into the incident as a mean of escape for occupants Scenario 8- Failure of the Fire Protection Systems This scenario involves a fire in case of a failure of sprinkler systems. This event happens in a living room in one of the residential apartments. The scenario involves a smoke spread in hallway, where the smoke mechanically ventilated to the roof. The fire does not necessarily represent the highest possible fuel load. 8. TRIAL DESIGNS AND EVALUATION 8.1 Trial Designs To evaluate the different design fire scenarios, models were created using Version 6 of the Fire Dynamics Simulator (FDS) and PyroSim software. Based on severity, separate geometries are developed and modified for each fire scenario. Material properties, fuel packages, ignition source, and fuel loads are defined separately for each trial design. Control devices such as heat and smoke detectors, thermocouples, and sprinklers are designed to evaluate the heat flux, temperature rise, and suppression time in design fires. Trial designs have a simulation time of 30-minutes (1,800-s). 8.2 Trial Design Evaluation To compare the findings from trial designs to tenability criteria, various monitoring devices are designed in each scenario, including: Heat Flux: Boundary layer files are developed to analyze the heat and temperature exposure. The maximum tenable radiant heat exposure is 2.5-kW/m 2 at head height (1.8-m). Convective Exposure (Air and Smoke Temperatures): Slice files are designed at the elevation of 1.8-m above the floor to measure the temperature rise in a fire event. Regarding the tenability criteria, a maximum of 60 ºC (140 ºF) for 30-minutes exposure is defined for the convective exposure of the occupants. 50

62 Visibility Distance: Slice files are developed at an elevation of 1.8-m above the floor to examine the smoke obscuration. Per tenability criteria, a maximum of 10- m visibility to doors and walls should be achieved. Smoke Toxicity: Slice files are also developed to analyze the soot yields, and CO and HCN concentrations. An average of 1,000-ppm of CO, and maximum of 100- ppm of HCN is defined as the tenability criteria for this case study. The output files from FDS are compared to tenability criteria and egress calculations (both hand and software) to define the Available Safe Time for Egress (ASET). This value is later compared to the Required Safe Time for Egress (RSET) in order to examine whether the design fires meet the tenability criteria or not. Regarding the absence of any fire simulation of tall CLT buildings, especially exposed assemblies, there were no documents to validate and verify these models. Authors tried their best to present the fire modeling in such structures. In addition, design fires bring uncertainties while modeling, and most suitable results are obtained from locations farther from the ignition source [74-76]. The following outlines the four fire scenarios chosen for evaluation Design Fire Scenario 1- Typical Occupancy-Specific Design Fire Scenario The first evaluated design fire scenario involves a kitchen fire in one of apartments in the CLT Tower. The ignition source is defined as an unattended pot containing canola oil. The physical properties of canola oil is summarized in Table 8.1 [62]. Table 8.1 Physical Properties of Canola Oil Flash Point [ C] Auto-Ignition Temperature [ C] Density [kg/ m 3 ] Specific Heat [kj/kg.k] Heat Release Rate [kw/m 2 ] ,080 The geometry includes two rooms, kitchen, a bathroom, and a closet. Walls are encapsulated with three layers of 15.9-mm (5/8-in.) type X gypsum board. As mentioned earlier, kitchen and bathroom s ceilings are not exposed, and protected with two gypsum board layers. Based on the floor plan, two wood cabinets are added on two sides of the stove. The fuel package is designed as a cuboid on top of the stove, where a metal piece is also designed at the elevation of 1.8-m (5.9-ft.) representing a hood. 51

63 Figure 8.1 Design Fire Scenario 1- Residential Kitchen Fire Thermocouples are located on multiple locations on the wall surface, between three layers of gypsum boards, and between the third gypsum board layer and the CLT wall assembly. A ramp fire is designed to rapidly reach a heat flux of 1,080 kw/m 2. Fire was initiated from a 0.2-m 0.2- m 0.-2-m pot on the stove. All doors were assumed to be closed during the simulation. An autoignition temperature of 340 C was considered. The simulation continued for 640-s (~10.5-min.), and no ignition was observed. The comparison between fire modeling outcomes and the tenability criteria is summarized in Table 8.2. Heat Flux [kw/m 2 ] Table 8.2 Design Fire Scenario 1 Summary Convective Exposure [ C] Visibility Distance [m] Smoke Toxicity [ppm] Tenability Criteria ,000.0 Design Fire 1 NA 26.0 (Temperature Slice Located Vertically 2-m from the Center of the Burner) >10.0 NA Design Fire Scenario 5- Slow Developing Shield Fire near a High-Occupancy Space This fire scenario evaluates a situation where an incident occurs in a normally unoccupied room adjacent or near a high occupancy area. For the CLT Tower, this fire starts in one of the changing rooms on level 9, where the room is occupied with people using the gym. The changing room s door was assumed to be open during the incident. The fire is located at the left changing room 52

64 adjacent to the left area of refuge. The smoke propagated to the gym area (left side), hallway, and gaming longue (area on the right). The door between this section and the elevator lobby was assumed to be closed during this scenario; smoke did not spread out of the geometry. The model s geometry is shown in Figure 8.2. Figure 8.2 Design Fire Scenario 5- Slow Developing Fire near a High-Occupancy Space The simulation is performed in the presence of a fast-response sprinkler, and a heat detector mounted on top of the middle locker close to the changing room. Upholstery is used as a fuel package. Changing room s walls are encapsulated with 15.9-mm (5/8-in.) type X gypsum board; three layers on the back wall (adjacent to the area of refuge) and one layer on the other two sides. The proposed changes to IBC 2021 by AH-TWB advises exterior protection of combustible walls [81]. Simulation is initially established as 1,800-s, however, limitations did not allow a run further than 376-s (~6.5-min.). Results from the trial run showed the sprinkler activation time of 213-s. The situation did not become untenable during the trial run. The comparison between fire modeling outcomes and the tenability criteria is summarized in Table 8.3. Table 8.3 Design Fire Scenario 5 Summary 53

65 Heat Flux Convective Exposure Visibility Distance Smoke Toxicity [kw/m 2 ] [ C] [m] [ppm] Tenability Criteria ,000.0 Design Fire 5 Max. HRR of kw 38.0 at the Middle Locker (Close to the Changing Room) >10.0 <1, Design Fire Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load This Scenario occurs in one of the rooms, considered as a work room, in a residential apartment. Two piles of cardboards were designed as fuel packages on two corners of the room alongside other combustibles such as bookshelves (full of books), a sofa, a table, and a wood chair. The configuration was selected to represent the highest possible fuel load [10]. To evaluate the possible fire propagation to the other parts of the apartment and outside, the work room s door and the entrance door are designed to be open. Figure 8.3 Design Fire Scenario 6- Most Severe Fire Associated with the Greatest Fuel Load 54

66 Three meshes are designed for this scenario: residential apartment, hallway, and elevator lobby. The entrance door to the left residential apartment is designed to remain close. As a result, this apartment and the area on the right side of the elevator lobby are assumed to be void during the simulation. A ramp fire is designed to rapidly reach a heat flux of 1,000 kw/m 2. The simulation using PyroSim runs for 76-s. Results show a rapid fire propagation to adjacent rooms and apartment, and smoke spread to hallway and the elevator lobby. Although 5 sprinklers are activated in the apartment, hallway, and the elevator lobby, the fire load is so large, it is not suppressed. A summary of results is shown in Table 8.4. Table 8.4 Design Fire Scenario 6 Summary Visibility Heat Flux Convective Exposure Smoke Toxicity Distance [kw/m 2 ] [ C] [ppm] [m] Tenability Criteria ,000.0 Design Fire 6 HRR of 1 MW 73.0 (Temperature Slice Located Vertically, 2-m from the Center of the Work Room) <10.0 >1,000.0 in the Work Room in the First 35-s Findings from this case scenario could not be validated, and computational limits do not allow the modeling beyond 76-s. Results show conditions become untenable in a short period of time after the fire initiation Scenario Fire 8- Failure of the Fire Protection Systems This scenario evaluates the fire and smoke behavior in absence of fire protection systems. It is assumed heat detectors and sprinklers malfunction during a maintenance event. As illustrated in Figure 8.4, the geometry includes common residential combustibles, such as a sofa and wooden tables. The fire initiates in the right sofa and propagated to the other two sofas and the coffee table. All doors, except the entrance door, are designed to be open to evaluate the smoke spread during the incident. Modeling stops at 566-s (~9.5-min); results indicate smoke spread throughout the apartment, but the temperature of the right wall (of the sofa) does not reach 400 C, as the window does not break. Likewise, the temperature of the adjacent wall to the TV does not reach 400 C during the simulation. 55

67 Figure 8.4 Design Fire Scenario 8- Failure of Sprinklers in a Residential Area The comparison between fire modeling outcomes and the tenability criteria is summarized in Table 8.4. Heat Flux [kw/m 2 ] Table 8.5 Design Fire Scenario 8 Summary Convective Exposure [ C] Visibility Distance [m] Smoke Toxicity [ppm] Tenability Criteria ,000.0 Design Fire 8 Max HRR of 480 kw 67.0 (Temperature Slice Located Vertically 2-m from the Center of Right Sofa) 8.3 Comparison of Fire Simulation to Fire Safety Goals and Objectives >10.0 <1,000.0 Four fire scenarios are evaluated for this case study and compared with the fire safety goals and objectives. Results from the simulation demonstrate life safety could be provided to occupants and firefighters in presence of fire protection systems. The latest fire study on exposed timber in ATF 56

68 laboratory shows the contribution of CLT assemblies increased with the increasing exposed surface area [79-80] Safeguard Occupants from Injury Due to Fire until They Reach a Safe Place This fire objective requires the designers to safeguard the occupants in a fire event. Regarding the two evacuation strategies defined for the CLT Tower, occupants either move to the area of refuge floors (L9, L17, and L25) for partial evacuation and defend-in-place, or to the ground floor (L1) for total evacuation. To ensure the safety of occupants with mobility impairments, areas of refuge are designed at stairway landings in each floor. Evacuation follows the OEO strategy and controlled from the FCC. Active and passive fire protection systems, alarm systems, pressurized stairways, mechanical ventilation, and fire elevators are designed to increase the tenability threshold and ensure the occupant s safety Safeguard Firefighters while Performing Rescue Operations or Attacking Fire This fire safety objective is fully explained in section Design to Avoid Structural Failure in the Event of Fire Based on the simulations, the surface temperature of the interior walls do not delaminate and/or develop failure of the CLT laminas. In other word, total (complete) encapsulation alongside sprinklers provides adequate level of safety for the structure; prevents burnout and collapse. 57

69 9. FINAL DESIGN DOCUMENTATION 9.1. General The 9 th Street Tower is designed with several performance-based features that exceed or provide an acceptable alternative the prescriptive requirements of the IBC. The mixed-use building is designed with the following fire safety goals: 1. Provide life safety to the public, building occupants, and firefighters during an emergency 2. Continuity of business operations 3. Property preservation 4. Decrease environmental impacts The primary fire safety objectives include: 1. Safeguard occupants from injury due to fire until they reach a safe place 2. Safeguard firefighters while performing rescue operations or attacking the fire 3. Design to avoid structural failure in the event of a fire 4. Design to avoid building-to-building fire spread 9.2. Fire Protection Features The performance-based design for the 9 th Street Tower includes the following fire protection and life safety features: Construction: The Tower is constructed of precast concrete and an engineered wood system. The glulam beams supporting the CLT floors/ceilings and CLT load bearing walls are combustible; complete encapsulation (sufficient gypsum board thickness on all sides to prevent any charring of the wood in a complete burnout [28] ) provides a 3-hr. fire-resistance rating. The CLT floors/ceiling are also combustible and complete encapsulation also provides a 3-hr. fire-resistance rating. The Carpark levels and Area of Refuge floors is non-combustible precast concrete with a 2-hr. fire resistance rating. All penetrations through the fire rated walls and floors must be done carefully to minimize pathways for the spread of fire and smoke [28]. All connection designs eliminate any 58

70 hidden voids to minimize pathways for the spread of fire and smoke. Fire stops are in the multistory vertical voids between the fire walls. Exit Stair: There is one stairwell in the Tower and is oversized to allow for bi-directional flow to facilitate the fire-fighting suppression operations. This stairway serves each floor in the Tower and is enclosed in a 2-hr. fire-rated construction. On each floor, the stair is provided with a 2-hr. rated vestibule where a fire department hose valve is provided, allowing fire department suppression operations. Areas of Refuge: In addition to the three building Areas of Refuge on Floor Levels 9, 17, and 25, each floor has a secured area of refuge located in the stairway and is enclosed in 2-hour rated smoke barriers. This area of refuge is available for persons who are unable to use the stairway; a safe place is provided to wait for assistance. 2-way communication with the Fire Command Center (FCC) of the building is provided in each area of refuge stair vestibule. Elevators: There are five elevators in the Tower; four passenger cars serve as occupant evacuation elevators (OEE) and one service elevator is designated for firefighting operations. These elevators are specially designed with 2-hr. fire resistive, smoke resistive construction, to allow egress during an emergency and are provided with a pressurized common lobby. The elevators are equipped with emergency power supply and each hoist way is designed as a smoke-proof enclosure. Emergency/Standby Power: The Tower is provided with two independent transformers, each connected to a separate electrical sub-station connected to the municipal power grid, creating a redundancy of the normal power supply. A primary natural gas driven generator is in the basement level of the Tower to provide emergency power should both normal power supplies fail. Emergency power is automatically activated within 30-s of normal power interruption. The emergency power supplies egress lighting and the fire alarm detection and communication system. The standby power supplies the elevators, smoke control elements, and the FCC. Communication System: An emergency voice/alarm communication system is provided in all elevators, at each exit stairway, each floor, and the stairway areas of refuge. Elevators, areas of refuge, and each apartment unit are equipped with a dedicated two-way communication system with the security/reception desk. The system is activated from the FCC. For two-way fire department communications, a repeater system is required by the Charlotte Fire Department. The main entrance/exit and the side entrances/exists include an intercom to communicate with the 59

71 security/reception desk. The parking garage vehicular entrance and exit is also provided with an intercom to communicate with the security/reception desk. Smoke Control: The area of refuge in each stairway on each floor is pressurized. The stairs and elevator hoist ways are also pressurized. HVAC systems are designed separately for each floor to minimize smoke migration. Smoke control initiates upon activation of the fire alarm system. Fire Alarm and Detection: The fire alarm system is designed in accordance with NFPA 72 [25]. Manual fire alarm boxes are located on every floor near the entrance to each stairway exit, red in color. There is complete smoke detection in the exit access corridors. Smoke detectors are photoelectric type and are in mechanical/electrical rooms, elevator lobbies, main exhaust and return of air ventilation. The automatic sprinkler system waterflow alarms are monitored and activates the building fire alarm system. The fire alarm system also supervises all sprinkler system control valves. Notification devices include horns in every occupied space within the building and ADAAG approved strobes in public and common areas, including P1, P2, L1, L9, L17, and L25, and the Roof Sky Deck. Alarm, supervisory, and trouble signals automatically transmit to the Ground Level Security Desk and an off-site central monitoring station. Local alarms sound, based on a phased evacuation. The fire alarm system activates the smoke control system on an area by area basis Fire Command Center: The Tower has a dedicated fire command center (FCC) on the Ground Floor Level, enclosed in a 2-hr fire resistance rated construction. The FCC is located adjacent to the south side exit enclosure; access is from the lobby or directly from the exterior. The fire alarm signaling, and voice communication panels are in the FCC. A panel showing the operation, location, and direction of each elevator used for OEE is also in the FCC. This panel includes controls by which the fire department can initiate elevator evacuation from any given floor. It is directly accessible from the main exit stair and the exterior at grade level. Automatic Sprinkler System and Standpipe System: The Tower is protected by an automatic sprinkler system. It is designed in accordance with NFPA 13 [13] and the following criteria: Residential Units: Light Hazard Mercantile Areas: Ordinary Hazard Group 2 Storage: Ordinary Hazard Group 2 Sky Deck: Light Hazard 60

72 Quick response sprinklers will be installed throughout the building, except where prohibited by their listing. Sprinkler system zones will coincide with the fire alarm system zones. Each floor will consist of a single fire alarm zone and sprinkler zone. All resident balconies with CLT ceilings will be sprinkler protected. Fire department connections (FDC) are located on the Ground Level near the South entrance/exit and will feed the combined sprinkler/standpipe system. The FDC location is within 200-ft. of an approved hydrant and with-in 50-ft. of access road. An approved fire hydrant is located within 750-ft. from the most remote point of the building and measured as the truck travels. Fire hose valve connections are combined with the building sprinkler system and are in the exit stair vestibule on each floor of the building. Roof storage tanks with captured rainwater provides an additional source for fire-fighting measures. Kitchen Fire Suppression: Each residential kitchen is equipped with a stand-alone, self-contained wet-chemical fire suppression system. This system provides dedicated protection of the range/cook top. This system must be regularly inspected and maintained to ensure proper operation. Portable Fire Extinguishers: One portable fire extinguisher (2A:10B: C rating) is placed in each residence unit of the Tower, retail spaces, each building amenity areas on the 9 th, 17 th, and 25 th floor levels, and in the residential corridors within 75-ft. of each dwelling unit, visible, and easily accessible. Multipurpose dry chemical extinguishers are placed throughout the mechanical areas of the Tower in accordance with NFPA 10: Portable Fire Extinguishers [10]. Staff Training: The Tower staff should be trained to help during an emergency evacuation. The employees of the retail areas shall also be trained to help during an emergency evacuation. Tower staff and retail employees should be trained to use the occupant emergency elevators. An assembly coordinator is assigned to account for building residents at the assigned assembly areas in case of an emergency evacuation, see the Fire and Emergency Plan in Appendix G Operations and Maintenance Manual An Operations and Maintenance (O&M) Manual is provided in Appendix F to ensure all components of the performance design are implemented and operating properly. The Manual also provides the fire protection features of the Tower and the interaction of the different fire protection systems. All associated inspections, testing regimes, and schedules are outlined. Some systems are 61

73 tested and inspected individually; the interconnections between systems are also tested periodically as well. The Manual also communicates to the residents and tenants of the Tower the limitations; details are provided, and an evacuation plan is also included. A fire safety checklist includes limits, such as no smoking or grilling on the premises. The design components that are critical to achieve the goals and objectives of the performance-based design must be maintained and a fire protection system maintenance plan for those components are outlined Fire/Emergency Plan A Fire/Emergency Plan is provided in Appendix G and ensures the specific emergency procedures are followed to minimize fire and life safety issues. The Plan provides guidance for the building occupants to know how to respond quickly and know their respective roles and responsibilities. The Plan outlines the procedures necessary during a fire, hurricane, flood, and bomb threat. On an annual basis, a professional instructor from the Occupational Safety and Health Administration (OSHA) or the National Fire Protection Agency (NFPA) should review how to operate a fire extinguisher as well as providing updates on any new and/or revised regulations with the building occupants. Also, a specific assembly place is designated to ensure all occupants are accounted for during an evacuation. 9.5 Fire and Life Safety During Construction A Fire and Life Safety Plan during Construction is outlined in Appendix H. The Plan is provided to ensure that specific procedures are followed to minimize fire and life safety exposure during construction of the Tower. Fire during construction can be even more damaging than a fire occurring in a completed building. This is associated with large areas of construction work without any fire suppression or the final fire protection systems not yet installed or operational [28]. The effects of a potential fire during the construction of the Tower is minimized by: daily practices to controlling the hazards on the Tower site; keeping combustibles away from ignition sources; providing adequate protection and detection as soon as possible; and working to ensure a prompt fire department response. 62

74 10. REFERENCES [1] NGCTS Fire Testing Laboratory, Standard Methods of Fire Tests of Building Construction and Material- AST M E119-11a. Retrieved from [Last Access: March 31, 2018]: [2] Southwest Research Institute, Fire Resistance Performance Evaluation of a Penetration Firestop System Tested in Accordance with ASTM E814-13A, Standard Test Method for Fire Tests of Penetration Fire Stop Systems. Retrieved from [Last Access: March 31, 2018]: E814_Penetration_Firestop_in_CLT-Final_Report.pdf [3] International Code Council, International Building Code. Country Club Hills, Ill: ICC. [4] Southwest Research Institute, Full-Scale Tests in a Furnished Living Room to Evaluate the Fire Performance of Protected Cross-Laminated and Nail Laminated Timber Construction. Retrieved from [Last Access: March 31, 2018]: Final_Report.pdf [5] National Fire Protection Association, Fire Safety Challenges of Tall Wood Buildings- Report on Cross Laminated Timber (CLT) Compartment Fire Tests. Retrieved from [Last Access: March 31, 2018]: [6] Zelinka, S.L.; Hasburgh, L.E.; Bourne, K.J.; Tucholski, D.R. Ouellette, J.P., Compartment Fire Testing of a Two-Story Mass Timber Building. General Technical Report FPL-GTR-247. Madison, WI. U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. Retrieved from [Last Access: March 31, 2018]: [7] ICC Ad Hoc Committee on Tall Wood Buildings, Retrieved from [Last Access: March 31, 2018]: [8] Ad Hoc Committee- Tall Wood Buildings, Staff Developed Draft of TWB Related Sections in the Upcoming 2018 IBC for Potential 2018/2019 Code Change Consideration. Retrieved from [Last Access: March 31, 2018]: ICodes_Sections.pdf [9] American National Standard, ANSI/APA PRG : Standard for Performance-Rated Cross- Laminated Timber. Published by APA The Engineered Wood Association South 19th Street Tacoma, WA [10] NFPA 101: Life Safety Code, 2018 Edition. In NFPA National Fire Codes Online. [Last Access: March 31, 2018]: [11] International Code Council, International Fire Code. Country Club Hills, Ill: ICC. Retrieved from [Last Access: March 31, 2018]: [12] American Forest & Paper Association, National Design Specification for Wood Construction (New Standard) NDS. Washington, D.C.: American Forest & Paper Association. [13] NFPA 13: Standard for the Installation of Sprinkler Systems, 2016 Edition. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [14] NFPA 14: Standard for the Installation of Private Fire Service Mains and Their Appurtenances, 2016 Edition. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [15] NFPA 72: National Fire Alarm and Signaling Code, 2016 Edition. In NFPA National Fire Codes Online. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [16] NFPA 10: Standard for Portable Fire Extinguishers, 2010 Edition. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [17] SFPE Engineering Guide to Performance-Based Fire Protection, 2 nd Edition, [18] United States Department of Justice- Civil rights Division, Americans with Disability Act (ADA) Standards for Accessible Design. Retrieved from [Last Access: March 31, 2018]: 63

75 [19] Van De Kuilen, J.W.G. et al., Very Tall Wooden Buildings with Cross-laminated Timber, the 12 th East Asia-Pacific Conference on Structural Engineering and Construction, Procedia Engineering Vol 14, pp [20] Lineham, Sean, et al., Structural Response of Fire-exposed Cross-laminated Timber Beams under Sustained Loads, Fire Safety Journal, Vol. 85, pp [21] USGBC, LEED 2009 for New Construction and Major Renovations, [22] Image Retrieved from [Last Access: March 31, 2018]: [23] Montgomery G., Impson D., Modern Design with Mass Timber Southeast Wood Solutions Fair, Charlotte, NC. [24] Image Retrieved from [Last Access: March 31, 2018]: [25] Gerard R., Barber D., Wolski A Fire Safety Challenges of Tall Wood Buildings, The Fire Protection Research Foundation. [26] Barber D., Determination of Fire Resistance Ratings for Glulam Connectors within US High Rise Timber Buildings. Image Retrieved from [Last Access: March 31, 2018]: [27] Schaffer, E.L., Charring Rate of Selected Woods-Transverse to Grain. Res. Pap. FPL 69. Madison, WI: USDA Forest Service, Forest Products Laboratory. Image Retrieved from [Last Access: March 31, 2018]: [28] Buchanan A., et al, Fire Resistance of Timber Structures. The National Institute of Standards and Technology (NIST). Retrieved from [Last Access: March 31, 2018]: [29] Kristensen, JS, et al. Fire Induced Reradiation underneath Photovoltaic Arrays on Flat Roofs. Fire and Materials. Vol. 42, Issue 3, pp 1-8. [30] Building evac Smart App. Retrieved from [Last Access: March 31, 2018]: [31] USGBC, LEED Reference Guide for Building Design and Construction. [32] Meacham, B., et al., Fire Safety Challenges of Green Buildings. The Fire Protection Research Foundation. [33] USGBC, LEED Reference Guide for Building Design and Construction Fact Sheet. Retrieved from [Last Access: March 31, 2018]: [34] Charlson, A., Appropriate CO 2 Factors for Timber. London: Arup. [35] Salvadori, V., The Development of a Tall Timber Building. The Architectural Challenges, the Examples, the Opportunities. Retrieved from [Last Access: March 31, 2018]: [36] Ward R., Patterson D., The Impact of Wood Use on North American Forests. American Wood Council (AWC). Retrieved from [Last Access: March 31, 2018]: TheImpactofWoodUseonNorthAmericanForests-1511.pdf [37] International Code Council, International Code Council Performance Code. Country Club Hills, Ill: ICC. Retrieved from [Last Access: March 31, 2018]: [38] Li F., Reiss M., Fire and Life Safety Challenges in Sustainable Tall Building Design.. International Journal of High-Rise Buildings Vol. 2, No. 1, pp [39] Gritzo L. et al., The Influence of Risk Factors on Sustainable Development. FM Global Research Division [40] Tidwell J., Murphy J., Bridging the Gap: Fire Safety and Green Buildings. National Association of State Fire Marshalls 64

76 [41] Lamont S., Ingolfsson S., High Rise Buildings with Combustible Exterior Wall Assemblies: Fire Risk Assessment Tool. The National Fire Protection Association. Retrieved from [Last Access: March 31, 2018]: [42] EFFECT Tool, External Façade Fire Evaluation and Comparison Tool. National Fire Protection Association. Retrieved from [Last Access: March 31, 2018]: Retrieved from [Last Access: March 31, 2018]: [43] National Institute of Standard and Technology. NIST Special Publication th Edition. Fire Dynamics Simulator User s Guide. Retrieved from [Last Access: March 31, 2018]: [44] Engineering Guide : Guidelines for Substantiating a Fire Model For a Given Application, Bethesda, Md.: Society of Fire Protection Engineers. [45] SFPE Engineering Standard on Calculating Fire Exposure to Structures, Bethesda, Md.: Society of Fire Protection Engineers. [46] Engineering Guide : Fire Safety for Very Tall Buildings, Country Club Hills, IL: International Code Council. [47] SFPE s Engineering Guide: Human Behavior in Fire, Bethesda, Md.: Society of Fire Protection Engineers. [48] Tubbs J., Meacham B., Egress Design Solutions: A Guide to Evacuation and Crowd Management Planning. John Wiley & Sons. [49] Hurley, M., SFPE Handbook of Fire Protection Engineering (5th Ed.). New York, NY: Springer New York. Doi: / [50] Cote, A. E., Fire Protection Handbook (Vol. 1 & 2). National Fire Protection Association. [51] Buchanan, A. H., Fire Engineering Design Guide. Centre for Advanced Engineering, University of Canterbury. [52] CIBSE, G. E., Fire Engineering. The Chartered Institution of Building Services Engineers, London, UK. [53] NFPA 130: Standard for Fixed Guideway Transit and Passenger Rail Systems, 2017 Edition. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [54] Gager III, A. H., Hughes, P. J., Dominguez, G., & Hughes, J. Tenability Criteria in Unique Situations and Atypical Buildings. Retrieved from [Last Access: March 31, 2018]: [55] City University of New York (CUNY) - Department of Geography, Oxygen and Human Requirements. Retrieved from [Last Access: March 31, 2018]: [56] Butler, K., Kuligowski, E., Furman, S. and Peacock, R., Perspectives of Occupants with Mobility Impairments on Evacuation Methods for Use during Fire Emergencies. Fire Safety Journal, 91, pp Retrieved from [Last Access: March 31, 2018]: [57] ANSI, B, ASME A17. 1-Safety Code for Elevators and Escalators. The American Society of Mechanical Engineers [58] Ronchi, E. P., & Nilsson, D., 2013) Assessment of Total Evacuation Systems for Tall Buildings: Literature Review. Quincy, MA: Fire Protection Research Foundation. Retrieved from [Last Access: March 31, 2018]: Retrieved from [Last Access: March 31, 2018]: [59] Kinateder, M. T., Omori, H., & Kuligowski, E. D., The Use of Elevators for Evacuation in Fire Emergencies in International Buildings. US Department of Commerce, National Institute of Standards and Technology. Retrieved from [Last Access: March 31, 2018]: design.ie/wp-content/uploads/2015/02/nist-tn-1825_international-use-of-elevators-for-fire- Evacuation_2014.pdf [60] McColl D., Use of Elevators during Emergencies. 3rd Annual CTBUH International Student Design Competition, Shanghai, China. 65

77 [61] NFPA 1: Fire Code, 2018 Edition. In NFPA National Fire Codes Online. In NFPA National Fire Codes Online. Retrieved from [Last Access: March 31, 2018]: [62] Liu, Z., Carpenter, D., & Kim, A. K., Characteristics of Large Cooking Oil Pool Fires and Their Extinguishment by Water Mist. Journal of Loss Prevention in the Process Industries, 19(6), [63] Koffel Associates Inc., Performance-Based Life Safety Assessment of the Four Corners World Tower. 9 th SFPE International Conference Performance-based Codes and Fire Safety Design Methods. June 20-22, Hong Kong. [64] Koffel Associates Inc., Performance-Based Design Analysis of Singular Tower. 7 th SFPE International Conference Performance-Based Codes and Fire Safety Design Methods. June 20-22, Auckland, New Zealand. [65] Klote, J. H., Alvord, D. M., & Deal, S., Routine for Analysis of the People Movement Time for Elevator Evacuation. National Institute of Standards and Technology, Building and Fire Research Laboratory. [66] Bukowski, R. W., Emergency Egress Strategies for Buildings. NIST, Gaithersburg, MD. [67] Kuligowski, E., & Bukowski, R. W., Design of Occupant Egress Systems for Tall Buildings. In CIB World Building Congress (Vol. 2004). Retrieved from [Last Access: March 31, 2018]: ss_systems_for_tall_buildings/links/5492f2e60cf22d7925d578cc.pdf [68] Buchanan, A. H., Fire Resistance of Multistorey Timber Buildings. In Fire Science and Technology 2015 (pp. 9-16). Springer, Singapore. [69] Östman, B., Brandon, D., & Frantzich, H., Fire Safety Engineering in Timber Buildings. Fire Safety Journal, 91, [70] Pei, S., Rammer, D., Popovski, M., Williamson, T., Line, P., & van de Lindt, J. W., An Overview of CLT Research and Implementation in North America. Proceeding of the World Conference on imber Engineering, August 22-25, 2016, Vienna, Austria. [71] Barber, D., & Gerard, R., Summary of the Fire Protection Foundation Report-Fire Safety Challenges of Tall Wood Buildings. Fire Science Reviews, 4(1), 5. [72] Brandon, D., & Östman, B., Fire Safety Challenges of Tall Wood Buildings Phase 2: Task 1-Literature Review. Fire Protection Research Foundation, Quincy, MA. [73] Brandon, D., & Östman, B., Fire Safety Challenges of Tall Wood Buildings Phase 2: Task 2&3-Cross Laminated Timber Compartment Fire Tests. Fire Protection Research Foundation, Quincy, MA. [74] Borg, A., Njå, O., & Torero, J. L., A Framework for Selecting Design Fires in Performance Based Fire Safety Engineering. Fire Technology, 51(4), [75] Gutiérrez-Montes, C., Sanmiguel-Rojas, E., Kaiser, A. S., & Viedma, A., Numerical Model and Validation Experiments of Atrium Enclosure Fire in a New Fire Test Facility. Building and Environment, 43(11), [76] Borg, A., Husted, B. P., & Njå, O., The Concept of Validation of Numerical Models for Consequence Analysis. Reliability Engineering & System Safety, 125, [77] American Wood Council (AWC) Tall Mass Timber Course Series, DES600 Tall Wood Structures: Current Trends and Related Code and Standard Changes [78] Smith J. B., American Wood Council (AWC) Tall Mass Timber Course Series, DES602 Tall Wood Structures: Fire Resistance Design Primer for Mass Timber Construction [79] Francis S., Smart J., American Wood Council (AWC) Tall Mass Timber Course Series, DES603 Fire Tests in Support of Tall Mass Timber Buildings [80] Francis S., Smart J., American Wood Council (AWC) Tall Mass Timber Course Series, DES604 CLT Adhesive Tests in Support of Tall Mass Timber Buildings [81] Francis S., Coats P., American Wood Council (AWC) Tall Mass Timber Course Series, DES605 Outcomes of ICC Tall Wood Ad Hoc Committee: Proposals and Discussion [82] Sutula J. and Ryder N., Quantifying the Hazards of green Building construction for Fire Investigation Analysis, International Symposium on Fire Investigation Science and Technology. 66

78 [83] Watts J. and Hall J., Introduction to Fire Risk Analysis. 5th Edition. SFPE Handbook of Fire Protection Engineering, Volume III, Chapter 72 [84] Watts J., Fire Risk Indexing. 5th Edition. SFPE Handbook of Fire Protection Engineering, Volume III, Chapter 82. [85] Meacham B. and Jutras I, Development of Objective-Criteria-Scenario triplets and Design Fires for Performance-Based Fire Safety Design. Journal of Building Engineering. Vol 8, pp [86] Short-Term Rentals Get 3 rd Degree in NYC, Retrieved from [Last Access: March 31, 2018]: [87] Horowitz S., Freelancing in America Study. Freelancers Union and Upwork. [88] Business News Daily. Retrieved from [Last Access: March 31, 2018]: [89] Meacham B. and Alvarez-Rodriguez, A., Risk Informed Performance-Based Design Concepts and Framework. National Institute of Standards and Technology. NIST GCR [90] Schmidt, J and Griffin, CT., Barriers to the Design and Use of Cross-Laminated Timber Structures in High-Rise Multi-Family Housing in the United States. Department of Architecture, Portland State University. [91] BSS Guardian Smart App. Retrieved from [Last Access: March 31, 2018]: [92] Managing Flexible Workers in the Emerging Gig Economy, [Last Access: March 31, 2018]: 67

79 APPENDIX A Floor Plans

80 Figure A.1 CLT Tower Site View (Retrieved from the Google Street View) A-1

81 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN LEVEL 1 SHEET TITLE L1 SCALE: 1/100 m FP.L1-GF DRAWING NUMBER A-2

82 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN, ALL LEVELS EXCEPT L1, L9, L17, AND L25 SHEET TITLE ALL LEVELS EXCEPT L1, L9, L17, AND L25 SCALE: 1/100 m FP.RESIDENTIAL.FLOORS DRAWING NUMBER A-3

83 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN LEVEL 9 SHEET TITLE L9 SCALE: 1/100 m FP.L9 DRAWING NUMBER A-4

84 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN LEVEL 17 SHEET TITLE FP.L17 L17 SCALE: 1/100 m DRAWING NUMBER A-5

85 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN LEVEL 25 SHEET TITLE FP.L25 L25 SCALE: 1/100 m DRAWING NUMBER A-6

86 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN PARKING P2 SHEET TITLE P2 SCALE: 1/100 m FP.P2 DRAWING NUMBER A-7

87 SFPE STUDENT CHAPTER AT THE UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE REVISIONS NO. DATE DESCRIPTION MILAD SHABANIAN DESIGNER S NAME SFPE 2018 PERFORMANCE- BASED DESIGN CASE STUDY PROJECT TITLE CROSS-LAMINATED TIMBER (CLT) HIGH-RISE RESIDENTIAL BUILDING BUILDING FLOOR PLAN PARKING P1 SHEET TITLE P1 SCALE: 1/100 m FP.P1 DRAWING NUMBER A-8

88 APPENDIX B Methodology and Structure of the Semi-Quantitative Approach Mitigation Strategies for Green Building Hazards Methodology and Structure of the Semi-Quantitative Approach after Mitigated Measures Validation and Sensitivity Analysis

89 Methodology and Structure of the Semi-Quantitative Approach Four levels of impacts are established and includes: No Impact: negligible adverse impact to life safety and property preservation Mild: minimal adverse impact to life safety and property preservation Moderate: marginal adverse impact to life safety and property preservation High: significant adverse impact to life safety and property preservation Numerical values are assigned to the four levels of impacts listed above and the Ranking Levels of Impact is distributed as follows: No Impact = 0 Points Mild Impact = 1 Point Moderate Impact = 2 Points High Impact = 3 Points The relative hazard level is estimated, as a weighted function of the importance or influence, of the hazard impact on the various green elements [32]. A hazard ranking matrix for the Tower is provided in Table B-1a below. Table B-1a: Matrix for Ranking Green Building Fire Hazards Green Building Feature Potential Ignition Hazard Potential Shock Hazard Potential Toxicity Hazard Contributes More Fuel Load Structural or Stability Issues Change Thermal Readily Characteristics Ignitable of Compartment Burns Readily Once Ignited Affects Burning Characteristics Significant Smoke Production/ Hazard Presents Flame Spread Concern May Impact Smoke/Heat Venting May Impact Occupant Evacuation May Impact Suppression Effectiveness May Impact Fire Apparatus Access Vegetative Roof System Battery Storage System Electric Vehicle Charging Station Increased Building Density Water Conservation: Captured Greywater Water Conservation: Captured Rainwater Reduced Water Supply Continuous Exterior Rigid Foam Insulation High-Performance Glazing Area of Combustible Façade Material Higher Insulation Values Refrigerant Materials Onsite Renewable PV Solar Power Energy Roof Panels Vestibules Solar Shadings from Perimeter Balconies Engineered Structural Wood Elements and Connections (CLT) Wood Interior Walls Low-emissivity & Reflective Coating Large Areas of Glazing (Daylight and Views) Site Selection Category Water Savings Category Energy Efficiency Category Material Selection Category Indoor Enviromental Quality Category Glass Interior Walls Horizontal Semi-open Floor Plans More Open Space - Vertical May Impact Fire Fighter Access TOTAL B-1

90 HAZARD RATING KEY None = 0 Low = 1 (Presents a Low Hazard when Unmitigated) Moderate = 2 (Presents a Moderate Hazard when Unmitigated) High = 3 (Presents a High Hazard when Unmitigated) Note: This is not a ranking in order of importance A total possible point value of 48 is established when all 16 hazard elements are valued as a high impact with 3 points each. Therefore, three project Impact Levels are categorized, and the hazard total rankings are distributed equally as follows: Mild: 0 16 Points Moderate: Points High: Points Some features present mild or moderate fire hazard to the Tower; several present a higher hazard. These fire hazards and level of severity for the Tower s green building elements are summarized in Table B-1b below. Table B-1b The Fire Hazards and Level of Impact for the Tower s Green Building Elements Site Selection Category Material/System/Attribute Hazard Ranking - Total Impact Level Vegetative Roof System 24 Moderate Battery Storage System 9 Mild Electric Vehicle Charging Station 13 Mild Increased Building Density 14 Mild Water Savings Category Material/System/Attribute Hazard Ranking - Total Impact Level Water Conservation: Captured Greywater 3 Mild Water Conservation: Captured Rainwater 3 Mild Reduced Water Supply 36 High Energy Efficiency Category Material/System/Attribute Hazard Ranking - Total Impact Level Continuous Exterior Rigid Foam Insulation 37 High High-Performance Glazing 13 Mild Area of Combustible Façade Material 32 High Higher Insulation Values 34 High Refrigerant Materials 16 Mild Onsite Renewable PV Solar Power Energy Roof Panels 21 Moderate Vestibule 6 Mild B-2

91 Solar shading from Perimeter Balconies 11 Mild Materials and Resources Category Material/System/Attribute Hazard Ranking - Total Impact Level Engineered Structural Wood Elements and Connections (CLT) 25 Moderate Wood Interior Walls 24 Moderate Indoor Environmental Quality Category Material/System/Attribute Hazard Ranking - Total Impact Level Low-emissivity & Reflective Coating 15 Mild Large Areas of Glazing (Daylight and Views) 27 Moderate Glass Interior Walls 18 Moderate Horizontal Semi-Open Floor Plans 25 Moderate More Open Space - Vertical 16 Mild Notably, the highest hazards occur in the Energy Efficiency Category and include attributes of a façade. While there is no statistical data linking all these variables of a combustible façade system on a high-rise building with the likelihood or consequence of a fire [42], the impact to the risk assessment for the Tower is evaluated to permit the combustible façade when the risk is deemed acceptable [42]. A total possible project point value of 1056 is established if all 22 green building initiative attributes listed in Table B-1 are valued at the highest impact concern level with 48 points each. Therefore, an overall Impact Level Ranking for the project is distributed equally as follows: Mild: Points Moderate: Points High: Points The overall hazard ranking of the Tower with the designed green building initiatives is 417 points. Based on the matrix methodology outlined above, the green building initiatives should impose a Moderate Impact Level on the Tower. However, the impact by the fire initiation or fire growth within the assemblies created by these green material components on the Tower can result in enhanced heat release rates and pathways of fire spread not typically observed with standard construction materials [82] ; a synergistic effect is created by the combination of the components and can be greater than the sum of its parts. As a result, there can be an increase in the level of hazards and concern for the Tower, over and above the 417-point value; the magnitude of a fire event can be affected. Therefore, mitigation strategies are implemented in the project design based B-3

92 on the synergy of the elements to reduce the fire hazards associated with the green building initiatives [29, 32, 40, 41, 42, 90], see Tables B2-B-6. Mitigation Strategies for Green Building Hazards Table B-2 Mitigation Strategies for Site Selection Category Material/System/Attribute Hazard Potential Mitigation Strategies Vegetative Roof System Contributes to fire load and flame spread; Impacts heat and smoke venting; Impacts firefighting and apparatus access; May impact structural stability Provide a good roof drainage system to prevent blockage and obstructions by growth media or other materials planted in the roof; Implement an Extensive (low-maintenance) design tolerant to drought and temperature extremes, using low growing succulents (high moisture content) and similar plants to enhance the roof's fire performance; Plants with high levels of volatile oils or resins should be avoided; Provide a 1 meter tall parapet to reduce flame spread to adjacent structures; Adequate access area for the fire department; Manage fire risk of vegetation Battery Storage System Electric Vehicle Charging Station Increased Building Density Ignition, shock, and toxicity hazard; contributes to fuel load; potential shock hazard to fire fighters; potential release of corrosive or toxic materials if damaged; Impacts firefighting access Ignition Hazard Ignition and flame spread hazard; May impact flame growth; Increase fire spread to adjacent structures; challenges for fire apparatus access Compartmentalize the storage area; special suppression system Shock protection; adequate/remote shutoff; special suppression system Limit planting and landscaping to reduce potential ignition source and additional avenues of fire spread; Drivable sidewalks for apparatus access; Develop Emergency Plan Table B-3 Mitigation Strategies for Water Savings Category Material/System/Attribute Hazard Potential Mitigation Strategies Water Conservation: Biological exposure hazard to fire fighters; Use for irrigation purposes only Captured Greywater corrosion of sprinkler piping system Water Conservation: Captured Rainwater for Suppression Reduced Water Supply Availability for suppression; system apparatus issues (hydrants/sprinklers) Unavailable for fire suppression; May impact fire growth and flame spread; Structural stability could be compromised Limit volume in water storage tanksexcess used to manage fire hazard of vegetated roof system; route overages to the grid Water storage tanks provided on 3 floors to meet minimum needs B-4

93 Table B-4 Mitigation Strategies for Energy Efficiency Category Material/System/Attribute Hazard Potential Mitigation Strategies NFPA 285 tested assembly; Readily ignitable; Expands towards the Projections to limit vertical and fire and can be treated as a fast or ultrafast horizontal spread; Use a fine closedcell structured material; Fire resistive Continuous Exterior Rigid fire; Contributes to fuel load, fire growth, Foam Insulation flame spread, smoke and toxic product barriers; Eliminate combustible foam development; Impacts egress and fire around base perimeter of the Tower; fighting Sprinklers High-Performance Glazing Area of Combustible Façade Material Higher Insulation Values Refrigerant Materials Onsite Renewable PV Solar Power Energy Roof Panels Changes thermal characteristics of burning compartment; may impact fire growth and flame spread; Impacts firefighting and apparatus access Larger area contributes to additional fuel load Alters compartment burning characteristics; additional fuel load; Impacts fire fighter access Potential ignition hazard; potential toxicity hazard; Presents flame spread concerns; May impact firefighting suppression efforts Ignition hazard; contributes to fuel load and flame spread; potential toxicity and shock hazard to fire fighters; potential glass breakage hazard; impacts fire fighter and apparatus access Insert breakout panels to help horizontal ventilation; Automatic Sprinklers; Adequate fire fighter access; Provide proper heat/smoke ventilation NFPA 285 tested assembly; Limited combustible material; Limit area on elevations; Eliminate combustible façade material at perimeter base of Tower; Eliminate façade vertical connectivity; Compartmentalize sections with projections to limit vertical and horizontal spread; No Smoking; No grilling on balconies. NFPA 285 tested assembly; Projections to limit vertical and horizontal spread; Sprinklers Special suppression system Use non-combustible roof materials, i.e. concrete for roof deck; provide thermal barrier between roof and PV cells; provide remote solar isolation switching close to solar units and in the FCC; system automatically shut off power to the buildings electrical system should the inverter lose power from the power company's grid [40] ; minimize height and inclination of units off roof to reduce flame and heat deflection [29] Vestibule Impacts fire fighter access Pre-incident planning Solar Shading from May impact ventilation; Firefighting Pre-incident planning Perimeter Balconies suppression can be impacted Table B-5 Mitigation Strategies for Materials and Resources Category Material/System/Attribute Hazard Potential Mitigation Strategies Engineered Structural Wood Elements and Connections (CLT) Contributes to Fuel Load; May impact egress and fire fighting Sprinklers; Additional layers for charring; Hidden Connections; Fire Resistive Barrier B-5

94 Wood Interior Walls Contribute to flame spread, smoke development, and fuel load Additional layers for charring; Hidden Connections; Sprinklers; Flame retardant treatment Table B-6 Mitigation Strategies for Indoor Environmental Quality Category Material/System/Attribute Hazard Potential Mitigation Strategies Changes thermal characteristics of Sprinklers; Adequate fire fighter Low-emissivity & Reflective burning compartment; Impacts fire access; Provide proper heat/smoke Coating fighting ventilation Large Areas of Glazing (Daylight and Views) Glass Interior Walls Horizontal Semi-Open Floor Plans (Open Spaces) Additional glass breakage for subsequent fire spread Inadequate fire barrier, glass breakage hazard; impact fire fighter access The lack of compartmentation may impact fire growth due to a greater volume of air, contributing to fire and smoke spread; Impact firefighting access Sprinklers; Projections to limit vertical and horizontal spread Sprinklers Automatic sprinklers; fire alarm systems; smoke control system; passive fire protection; fire safety and evacuation planning 1 Limited combustible is defined as: The material, in the form in which it is used, exhibits a potential heat value not exceeding 8141 kj/kg (3500 Btu/lb), when tested in accordance with NFPA 259, Standard Test Method for Potential Heat of Building Materials; And, The material shall have a structural base of non-combustible material with a surfacing not exceeding a thickness of 3.2 mm where the surfacing exhibits a flame spread index not greater than 50 when tested in accordance with ASTM E 84, Standard Test Method for Surface Burning Characteristics of Building Materials, or ANSI/UL 723, Standard for Test for Surface Burning Characteristics of Building Materials; Or, the material shall be composed of materials that in the form and thickness used, neither exhibit a flame spread index greater than 25 nor evidence of continued progressive combustion when tested in accordance with ASTM E 84 or ANSI/UL 723 and are of such composition that all surfaces that would be exposed by cutting through the material on any plane would neither exhibit a flame spread index greater than 25 nor exhibit evidence of continued progressive combustion when tested in accordance with ASTM E 84 or ANSI/UL 723; Or, a material that is classified as A2 by the EN test series [42]. B-6

95 Methodology and Structure of the Semi-Quantitative Approach after Mitigated Measures A hazard ranking matrix for the mitigated strategies implemented above is provided in Table B-7 below. Table B-7 Matrix for Ranking Green Building Fire Hazards with Mitigated Strategies Green Building Feature Potential Ignition Hazard Potential Shock Hazard Potential Toxicity Hazard Contributes More Fuel Load Structural or Stability Issues Change Thermal Readily Characteristics Ignitable of Compartment Burns Readily Once Ignited Affects Burning Characteristics Significant Smoke Production/ Hazard Presents Flame Spread Concern May Impact Smoke/Heat Venting May Impact Occupant Evacuation May Impact Suppression Effectiveness May Impact Fire Apparatus Access Vegetative Roof System Battery Storage System Electric Vehicle Charging Station Increased Building Density Water Conservation: Captured Greywater Water Conservation: Captured Rainwater Reduced Water Supply Continuous Exterior Rigid Foam Insulation High-Performance Glazing Area of Combustible Façade Material Higher Insulation Values Refrigerant Materials Onsite Renewable PV Solar Power Energy Roof Panels Vestibules Solar Shadings from Perimeter Balconies Engineered Structural Wood Elements and Connections (CLT) Wood Interior Walls Low-emissivity & Reflective Coating Large Areas of Glazing (Daylight and Views) Site Selection Category Water Savings Category Energy Efficiency Category Material Selection Category Indoor Enviromental Quality Category Glass Interior Walls Horizontal Semi-open Floor Plans More Open Space - Vertical May Impact Fire Fighter Access TOTAL HAZARD RATING KEY None = 0 Mild = 1 (Presents a Mild Hazard when Mitigated) Moderate = 2 (Presents a Moderate Hazard when Mitigated) High = 3 (Presents a High Hazard when Mitigated) Green Building Feature Total Hazard Scale MILD: 0-16 Points Moderate: Points High: Points Many mitigation strategies reduce the Impact Levels, altering the risk hazard for the Tower. These fire hazards and level of severity for the Tower s green building elements after mitigation are summarized in Table B-8. B-7

96 Table B-8 The Fire Hazards and Level of Impact on the Tower after Mitigation Strategies Site Selection Category Material/System/Attribute Hazard Ranking - Total Impact Level Vegetative Roof System 16 Mild Battery Storage System 9 Mild Electric Vehicle Charging Station 13 Mild Increased Building Density 11 Moderate Water Savings Category Material/System/Attribute Hazard Ranking - Total Impact Level Water Conservation: Captured Greywater 3 Mild Water Conservation: Captured Rainwater 3 Mild Reduced Water Supply 23 Moderate Energy Efficiency Category Material/System/Attribute Hazard Ranking - Total Impact Level Continuous Exterior Rigid Foam Insulation 23 Moderate High-Performance Glazing 10 Mild Area of Combustible Façade Material 16 Mild Higher Insulation Values 23 Moderate Refrigerant Materials 15 Mild Onsite Renewable PV Solar Power Energy Roof Panels 14 Mild Vestibule 6 Mild Solar shading from Perimeter Balconies 11 Mild Materials and Resources Category Material/System/Attribute Hazard Ranking - Total Impact Level Engineered Structural Wood Elements and Connections (CLT) 12 Mild Wood Interior Walls 12 Mild Indoor Environmental Quality Category Material/System/Attribute Hazard Ranking - Total Impact Level Low-emissivity & Reflective Coating 12 Mild Large Areas of Glazing (Daylight and Views) 16 Mild Glass Interior Walls 15 Mild Horizontal Semi-Open Floor Plans 18 Moderate More Open Space - Vertical 16 Mild The overall hazard ranking of the Tower, with the mitigated measures, or trial design option [89], for the designed green building initiatives, reduces to 297 points, imposing a Mild Impact Level B-8

97 on the Tower. The greatest individual reductions occur in the façade elements in the Energy Efficiency Category, including the continuous insulation, area of combustible façade material, higher insulation values, and large areas of glazing. The synergistic effect of these green building façade initiatives is considered during the analysis and reflected in the Impact Reductions, see Table B-9. Table B-9 Greatest Impact Reductions after Mitigation Strategies Site Selection Category Material/System/Attribute Impact Reduction Reduction Percentage Vegetative Roof System 8 Points 33% Water Savings Category Material/System/Attribute Impact Reduction Reduction Percentage Reduced Water Supply 19 45% Energy Efficiency Category Material/System/Attribute Impact Reduction Reduction Percentage Continuous Exterior Rigid Foam Insulation 14 Points 33% Area of Combustible Façade Material 14 Points 47% Higher Insulation Values 11 Points 33% Onsite Renewable PV Solar Power Energy Roof Panels Materials and Resources Category 7 Points 33% Material/System/Attribute Impact Reduction Reduction Percentage Engineered Structural Wood Elements and Connections (CLT) 13 Points 52% Wood Interior Walls 12 Points 50% Indoor Environmental Quality Category Material/System/Attribute Impact Reduction Reduction Percentage Large Areas of Glazing (Daylight and Views) 11 Points 41% Mitigation strategies used in isolation can lead to a disconnect between the measures and the actual expected performance of the building systems [89]. As a result, this analysis mitigates fire risks in the context of the overall system performance [89]. B-9

98 Validation and Sensitivity Analysis To evaluate the technique developed for this case study, a comparison fire risk assessment was performed using the NFPA External Façade Fire Evaluation and Comparison Tool (EFFECT). It is qualitative in nature and builds upon the concepts in Publicly Available Specification (PAS) 79 in the context of a fire spreading over multiple stories of a building via a combustible façade system [41]. The PAS 79 approach defines 9 steps to the qualitative risk assessment, see Figure below. The PAS 79 risk rankings in ascending order include: Trivial, Tolerable, Moderate, Substantial and Intolerable. The process of this risk assessment identifies the hazard(s) and then assess the likelihood and consequence of the hazards occurring; the EFFECT User's guide summarizes the methodology embedded in the FRA tool. Validation Methodology The preliminary Tower façade characteristics, prior to the implemented mitigation measures, are entered into the EFFECT tool. Assumptions include: The hypothetical case study is an existing structure Maintenance and operation of systems are in proper working condition The structural framing system is non-combustible B-10

99 Risk during construction of the Tower is not considered The goals considered are life safety and property preservation Results The façade fire hazard received a Risk Score of C, a moderate fire hazard. The likelihood of a fire hazard is medium; normal fire hazards (e.g. potential ignition sources) for this type of occupancy, with fire hazards generally subject to appropriate controls (other than minor shortcomings) [41]. The potential consequences of fire hazard indicate moderate harm; outbreak of fire could foreseeably result in injury (including serious injury) of one or more occupants but unlikely to involve multiple fatalities [41]. According to the EFFECT tool, it is essential that efforts are made to reduce the risk. Risk reduction measures, which should take cost into account, should be implemented within a defined time period. Where moderate risk is associated with consequences that constitute harm, further assessment might be required to establish more precisely the likelihood of harm as a basis for determining the priority for improved control measures [41]. See Figure below. Implementation of Mitigation Measures The Tower characteristics, after the implemented mitigation measures, were entered into the EFFECT tool and considered the same assumptions as indicated above. The façade fire hazard with the mitigated measures received a Risk Score of A, a trivial fire hazard. The likelihood of a fire hazard is low; unusually low likelihood of a fire as a result of negligible potential of ignition [41]. The potential consequences of fire hazard indicate slight harm; B-11

100 outbreak of fire unlikely to result in serious injury or death of any occupant (other than the occupant sleeping in a room in which a fire occurs) [41]. According to the EFFECT tool, no action is required, and no details need to be kept [41]. See Figure below. Discussion The approach of the validation assessment performs a systematic comparison of the EFFECT model results to the experimental data from the semi-quantitative approach for the façade developed for this case study. The EFFECT model results parallel the outcome of the semiquantitative technique analysis, developed for this case study, of the fire hazard from the green building initiatives on the façade. It is identified, however, several limitations, including: The tool is not applicable to timber frame buildings. The structural frame should be steel or concrete. The tool is a qualitative technique The tool addresses life safety only. Operations continuity and property preservation is not considered. The tool is for use in assessing existing buildings with a possible combustible façade system. It is not a design tool and should not be used for design of new buildings. There is limited statistical data on fires involving the exterior façade system. Test data is largely proprietary and therefore generally not available to inform this study with the exception of test data explicitly cited by this work. B-12

101 The tool assesses buildings in their completed state; i.e. it does not assess temporary risks that arise from construction work or partially occupied buildings; there are clear guidelines and tools available to assess those. The FRA tool is applicable in any geography but is currently limited to residential (hotel, apartments) or business (office) type occupancies that are over 18m high where height is measured as the vertical distance from fire department access level to the top most occupied floor of the building. The tool is distributed by NFPA as a risk assessment tool for use by an Authority Having Jurisdiction (AHJ). While other parties (owners, facilities managers, fire safety engineers, fire risk assessors) may also use the tool, it is developed with the NFPA specified end users in mind. Sensitivity Analysis The robustness of the results is reviewed to quantify the uncertainty, optimize the design, and to rank the influence of the various fire hazard variables of the technique. A sensitivity analysis provides a complete understanding of the influence of the different input parameters on the model outcome. Methodology The goals considered for the analysis correspond with the semi-quantitative approach: life safety and property preservation. The semi-quantification approach analyzes the impact of 16 fire hazard variables on 22 green building initiatives on the Tower. To understand the sensitivity to the 16 fire hazard impacts, each green building initiative is reviewed to determine the six most significant fire hazards impacting the initiative. The evaluation of attributes versus fewer, more concentrated parameters, may not impact the outcome; the reduced time needed to complete the process encourages participation for a consensus of professional judgement. B-13

102 APPENDIX C LEED 2009 Tower Certification Requirements and Credits [31]

103 The LEED 2009 Minimum Program Requirements for the CLT Tower are: Compliance with all applicable federal, state, and local building-related environmental laws and regulations in Charlotte, North Carolina A complete, permanent building designed for, constructed on, and operated on already existing land Use of a reasonable site boundary A minimum of 1,000-ft. 2 (9-m 2 ) of gross floor area Serves 1 or more Full Time Equivalent (FTE) occupant(s) Sharing whole-building energy and water usage data Gross floor area must be no less than 2% of the gross land area within the LEED project boundary The following are the LEED 2009 categories and credits allocated to the CLT Tower. All credits denoted with an asterisk (*) present moderate to high hazards while considering the performancebased design for the Tower. Sustainable Sites SS Prerequisite 1: Construction Activity Pollution Prevention Required Intent: Create and implement an erosion and sedimentation control plan for all construction activities associated with the project SS Credit 1: Site Selection (1 Point) To avoid the development of inappropriate sites and reduce the environmental impact from the location of a building on a site. *SS Credit 2: Development Density and Community Connectivity (5 Points) Intent: To channel development to urban areas with existing infrastructure, protect Greenfields, and preserve habitat and natural resources. Requirements OPTION 1. Development Density Construct or renovate a building on a previously developed site AND in a community with a minimum density of 60,000 ft. 2 per acre net. The density calculation is based on a typical two-story downtown development and includes the area of the project being built. Potential Technologies & Strategies During the site selection process, give preference to urban sites with pedestrian access to a variety of services. SS Credit 3: Brownfield Redevelopment (1 Point) Intent: To rehabilitate damaged sites where development is complicated by environmental contamination and to reduce pressure on undeveloped land. Requirements C-1

104 OPTION 2 Develop on a site defined as a brownfield by a local, state, or federal government agency SS Credit 4.1: Alternative Transportation Public Transportation Access (6 Points) Intent: To reduce pollution and land development impacts from automobile use. Requirements OPTION 1. Rail Station Proximity Locate the project within 1/2-mile walking distance (measured from a main building entrance) of an existing or planned and funded commuter rail, light rail or subway station. SS Credit 4.2: Alternative Transportation Bicycle Storage (1 Point) Intent: To reduce pollution and land development impacts from automobile use. Requirements CASE 2. Residential Projects: Provide covered storage facilities for securing bicycles for 15% or more of building occupants. SS Credit 4.3: Alternative Transportation Low-Emitting and Fuel-Efficient Vehicles (3 Points) Intent: To reduce pollution and land development impacts from automobile use. Requirements OPTION 1 Provide preferred parking for low-emitting and fuel-efficient vehicles for 5% of the total vehicle parking capacity of the site. Providing a discounted parking rate is an acceptable substitute for preferred parking for low-emitting/ fuel-efficient vehicles. To establish a meaningful incentive in all potential markets, the parking rate must be discounted at least 20%. The discounted rate must be available to all customers (i.e., not limited to the number of customers equal to 5% of the vehicle parking capacity), publicly posted at the entrance of the parking area and available for a minimum of 2 years. Potential Technologies & Strategies Provide transportation amenities such as alternative-fuel refueling stations. The costs and benefits of refueling stations will be shared with neighbors SS Credit 4.4: Alternative Transportation Parking Capacity (2 Points) Intent: To reduce pollution and land development impacts from automobile use. CASE 2. Residential Projects OPTION 1 Size parking capacity to meet but not exceed minimum local zoning requirements Provide infrastructure and support programs to facilitate shared vehicle use such as carpool dropoff areas, designated parking for vanpools, car-share services, ride boards and shuttle services to mass transit. Potential Technologies & Strategies The parking lot/garage size is minimum; adjacent buildings with parking facilities will be utilized. Consider alternatives that will limit the use of single occupancy vehicles. *SS Credit 5.2: Site Development Maximize Open Space (1 Point) C-2

105 Intent: To promote biodiversity by providing a high ratio of open space to development footprint. Requirements CASE 3. Sites with Zoning Ordinances but No Open Space Requirements Provide vegetated open space equal to 20% of the project site area. For projects in urban areas that earn SS Credit 2: Development Density and Community Connectivity, vegetated roof areas can contribute to credit compliance. Potential Technologies & Strategies Strategies include stacking the building program, tuck-under parking and sharing parking facilities with neighbors to maximize the amount of open space on the site. *SS Credit 6.1: Stormwater Design Quantity Control (1 Point) Intent: To limit disruption of natural hydrology by reducing impervious cover, increasing on-site infiltration, reducing or eliminating pollution from stormwater runoff and eliminating contaminants. Requirements CASE 2. Sites with Existing Imperviousness Greater Than 50% Implement a stormwater management plan that results in a 25% decrease in the volume of stormwater runoff from the 2-year 24-hour design storm. Potential Technologies & Strategies Specify vegetated roofs (but not pervious ground surfaces as they cannot handle the weight of fire trucks) and other measures to minimize impervious surfaces. Reuse stormwater for non-potable uses such as landscape irrigation, toilet and urinal flushing, and custodial uses. *SS Credit 6.2: Stormwater Design Quality Control (1 Point) Intent: To limit disruption and pollution of natural water flows by managing stormwater runoff. Requirements Implement a stormwater management plan that reduces impervious cover, promotes infiltration and captures and treats the stormwater runoff from 90% of the average annual rainfall1 using acceptable best management practices (BMPs). Runoff must remove 80% of the average annual post development total suspended solids (TSS) load based on existing monitoring reports. BMPs are considered to meet these criteria if they are designed in accordance with standards and specifications from a state or local program that has adopted these performance standards. Potential Technologies & Strategies Use alternative surfaces (vegetated roofs and grid pavers) and nonstructural techniques (rain gardens and rainwater recycling) to reduce imperviousness and promote infiltration and thereby reduce pollutant loadings. *SS Credit 7.1: Heat Island Effect Non-roof (1 Point) Intent: To reduce heat islands (thermal gradient differences between developed and undeveloped areas) to minimize impacts on microclimates and human and wildlife habitats. C-3

106 Requirements OPTION 2 Place a minimum of 50% of parking spaces under cover (parking underground, under deck, under roof, or under a building). Any roof used to shade or cover parking must have an SRI of at least 29, be a vegetated green roof or be covered by solar panels that produce energy used to offset some nonrenewable resource use. Potential Technologies & Strategies Employ strategies, materials and landscaping techniques that reduce the heat absorption of exterior materials. Use new coatings and integral colorants for asphalt to achieve light-colored surfaces instead of blacktop. Replace constructed surfaces (e.g., roof, roads, sidewalks, etc.) with vegetated surfaces such as vegetated roofs and open grid paving or specify high-albedo materials, such as concrete, to reduce heat absorption. *SS Credit 7.2: Heat Island Effect Roof (1 Point) Intent: To reduce heat islands to minimize impacts on microclimates and human and wildlife habitats. Requirements OPTION 2 Install a vegetated roof that covers at least 50% of the roof area. Water Efficiency WE Prerequisite 1: Water Use Reduction Required Intent: To increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems. Requirements Employ strategies that in aggregate use 20% less water based on estimated occupant usage and must include only the following fixtures and fixture fittings: water closets, urinals, lavatory faucets, showers, kitchen sink faucets. Potential Technologies & Strategies WaterSense-certified fixtures and fixture fittings should be used where available. Use highefficiency fixtures (e.g., water closets and urinals) and dry fixtures, such as toilets attached to composting systems, to reduce potable water demand. Consider using alternative on-site sources of water (e.g., rainwater, stormwater, and air conditioner condensate) and graywater for non-potable applications such as custodial uses and toilet and urinal flushing. WE Credit 1: Water Efficient Landscaping (2 Points) Intent: To limit the use of potable water or other natural surface or subsurface water resources available on or near the project site for landscape irrigation. Requirements OPTION 1. Reduce by 50% (2 points) Reduce potable water consumption for irrigation by 50% from a calculated midsummer baseline case. Reductions must be attributed to any combination of the following items: Plant species, density and microclimate factor Irrigation efficiency Use of captured rainwater C-4

107 Use of recycled wastewater Potential Technologies & Strategies Perform a soil/climate analysis to determine appropriate plant material and design the landscape with native or adapted plants to reduce or eliminate irrigation requirements. Where irrigation is required, use high-efficiency equipment and/or climate-based controllers. WE Credit 3: Water Use Reduction (2 Points) Intent: To further increase water efficiency within buildings to reduce the burden on municipal water supply and wastewater systems. Requirements Employ strategies that in aggregate use 30% less water than the water use baseline calculated for the building (not including irrigation). Energy and Atmosphere EA Prerequisite 1: Fundamental Commissioning of Building Energy Systems Required Intent: To verify that the project s energy-related systems are installed, and calibrated to perform according to the owner s project requirements, basis of design and construction documents. *EA Prerequisite 2: Minimum Energy Performance Required Intent: To establish the minimum level of energy efficiency for the proposed building and systems to reduce environmental and economic impacts associated with excessive energy use. OPTION 1. Whole Building Energy Simulation Demonstrate a 10% improvement in the proposed building performance rating for new buildings compared with the baseline building performance rating. Calculate the baseline building performance rating according to the building performance rating method in Appendix G of ANSI/ASHRAE/IESNA Standard (with errata but without addenda1) using a computer simulation model for the whole building project. Appendix G of Standard requires that the energy analysis done for the building performance rating method include all energy costs associated with the building project. To achieve points using this credit, the proposed design must meet the following criteria: Comply with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard (with errata but without addenda). Include all energy costs associated with the building project. Compare against a baseline building that complies with Appendix G of Standard (with errata but without addenda1). The default process energy cost is 25% of the total energy cost for the baseline building. If the building s process energy cost is less than 25% of the baseline building energy cost, the LEED submittal must include documentation substantiating that process energy inputs are appropriate. C-5

108 For this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators, kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps). Regulated (non-process) energy includes lighting (for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilation and air conditioning (HVAC) (for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes. Process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard G2.5) to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and the proposed design, and theoretical or empirical information supporting these assumptions. EA Prerequisite 3: Fundamental Refrigerant Management Required Intent: To reduce stratospheric ozone depletion. Requirements Zero use of chlorofluorocarbon (CFC)-based refrigerants in new base building heating, ventilating, air conditioning, and refrigeration (HVAC&R) systems. *EA Credit 1: Optimize Energy Performance (3 Points) Intent: To achieve increasing levels of energy performance beyond the prerequisite standard to reduce environmental and economic impacts associated with excessive energy use. OPTION 1. Whole Building Energy Simulation Demonstrate 16% improvement in the proposed building performance rating compared with the baseline building performance rating. Baseline building performance calculated according to Appendix G of ANSI/ASHRAE/IESNA Standard (with errata but without addenda1) using a computer simulation model for the whole building project. Appendix G of Standard requires that the energy analysis done for the building performance rating method include all the energy costs associated with the building project. To achieve points under this credit, the proposed design must meet the following criteria: Compliance with the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) in Standard (with errata but without addenda). Inclusion of all the energy costs within and associated with the building project. Comparison against a baseline building that complies with Appendix G of Standard (with errata but without addenda). The default process energy cost is 25% of the total energy cost for the baseline building. If the building s process energy cost is less than 25% of the baseline building energy cost, the C-6

109 LEED submittal must include documentation substantiating that process energy inputs are appropriate. For this analysis, process energy is considered to include, but is not limited to, office and general miscellaneous equipment, computers, elevators and escalators, kitchen cooking and refrigeration, laundry washing and drying, lighting exempt from the lighting power allowance (e.g., lighting integral to medical equipment) and other (e.g., waterfall pumps). Regulated (non-process) energy includes lighting (e.g., for the interior, parking garage, surface parking, façade, or building grounds, etc. except as noted above), heating, ventilating, and air conditioning (HVAC) (e.g., for space heating, space cooling, fans, pumps, toilet exhaust, parking garage ventilation, kitchen hood exhaust, etc.), and service water heating for domestic or space heating purposes. For this credit, process loads must be identical for both the baseline building performance rating and the proposed building performance rating. However, project teams may follow the exceptional calculation method ANSI/ASHRAE/IESNA Standard G2.5) to document measures that reduce process loads. Documentation of process load energy savings must include a list of the assumptions made for both the base and proposed design, and theoretical or empirical information supporting these assumptions. Potential Technologies & Strategies Design the building envelope and systems to maximize energy performance. Use a computer simulation model to assess the energy performance and identify the most cost-effective energy efficiency measures. Quantify energy performance compared with a baseline building. If local code has demonstrated quantitative and textual equivalence following, at a minimum, the U.S. Department of Energy (DOE) standard process for commercial energy code determination, the results of that analysis may be used to correlate local code performance with ANSI/ASHRAE/IESNA Standard *EA Credit 2: On-Site Renewable Energy (2 Point) Intent: To encourage and recognize increasing levels of on-site renewable energy self-supply to reduce environmental and economic impacts associated with fossil fuel energy use. Requirements Use on-site renewable energy systems to offset building energy costs. Calculate project performance by expressing the energy produced by the renewable solar power system as 3% of the building s annual energy cost. Use the building annual energy cost calculated in EA Credit 1: Optimize Energy Performance or the U.S. Department of Energy s Commercial Buildings Energy Consumption Survey database to determine the estimated electricity use. Potential Technologies & Strategies Assess the project for nonpolluting and renewable energy potential including solar, wind, geothermal, low-impact hydro, biomass, and bio-gas strategies. C-7

110 EA Credit 4: Enhanced Refrigerant Management (2 Points) Intent: To reduce ozone depletion and support early compliance with the Montreal Protocol while minimizing direct contributions to climate change. Requirements OPTION 2 Select refrigerants and heating, ventilation, air conditioning and refrigeration (HVAC&R) equipment that minimize or eliminate the emission of compounds that contribute to ozone depletion and climate change. The base building HVAC&R equipment must comply with the following formula, which sets a maximum threshold for the combined contributions to ozone depletion and global warming potential. Small HVAC units (defined as containing less than 0.5 pounds of refrigerant) and other equipment, such as standard refrigerators, small water coolers and any other cooling equipment that contains less than 0.5 pounds of refrigerant, are not considered part of the base building system and are not subject to the requirements of this credit. Do not operate or install fire suppression systems that contain ozone-depleting substances such as CFCs, hydrochlorofluorocarbons (HCFCs) or halons. EA Credit 6: Green Power (2 Points) Intent: To encourage the development and use of grid-source, renewable energy technologies on a net zero pollution basis. Requirements Engage in at least a 2-year renewable energy contract to provide at least 35% of the building s electricity from renewable sources, as defined by the Center for Resource Solutions Green-e Energy product certification requirements. All purchases of green power shall be based on the quantity of energy consumed, not the cost. OPTION 1. Determine Baseline Electricity Use Use the annual electricity consumption from the results of EA Credit 1: Optimize Energy Performance Potential Technologies & Strategies Determine the energy needs of the building and investigate opportunities to engage in a green power contract. Green power is derived from solar, wind, geothermal, biomass or low-impact hydro sources. Visit for details about the Green-e Energy program. The green power product purchased to comply with credit requirements need not be Green-e Energy certified. Other sources of green power are eligible if they satisfy the Green-e Energy program s technical requirements. Renewable energy certificates (RECs), tradable renewable certificates (TRCs), green tags and other forms of green power that comply with the technical requirements of the Green-e Energy program may be used to document compliance with this credit. Materials and Resources *MR Prerequisite 1: Storage and Collection of Recyclables Required Intent: To facilitate the reduction of waste generated by building occupants that is hauled to and disposed of in landfills. Requirements C-8

111 Provide an easily-accessible dedicated area or areas for the collection and storage of materials for recycling for the entire building. Materials must include, at a minimum: paper, corrugated cardboard, glass, plastics and metals. *MR Credit 2: Construction Waste Management (2 Points) Intent: To divert construction and demolition debris from disposal in landfills and incineration facilities. Redirect recyclable recovered resources back to the manufacturing process and reusable materials to appropriate sites. Requirements Recycle and/or salvage nonhazardous construction and demolition debris. Develop and implement a construction waste management plan that, at a minimum, identifies the materials to be diverted from disposal and whether the materials will be sorted on-site or comingled. Excavated soil and land-clearing debris do not contribute to this credit. The minimum percentage debris to be recycled or salvaged is 75%. Potential Technologies & Strategies Diversion from disposal in landfills and incineration facilities; adopt a construction waste management plan. Recycle all cardboard, metal, brick, mineral fiber panel, concrete, plastic, clean wood, glass, gypsum wallboard, carpet and insulation. Construction debris processed into a recycled content commodity that has an open market value (e.g., wood derived fuel [WDF], alternative daily cover material, etc.) may be applied to the construction waste calculation. Designated area on the construction site is provided for segregated or comingled collection of recyclable materials but must be considered as a fire hazard during the construction phase. MR Credit 3: Materials Reuse (1 Point) Intent: To reuse building materials and products to reduce demand for virgin materials and reduce waste, thereby lessening impacts associated with the extraction and processing of virgin resources. Requirements Use salvaged, refurbished or reused materials, the sum of which constitutes at least 5%, based on cost, of the total value of materials on the project. Mechanical, electrical and plumbing components and specialty items such as elevators and equipment cannot be included in this calculation. Only materials permanently installed in the project are used. Furniture is included as it is included consistently in MR Credit 3: Materials Reuse through MR Credit 7: Certified Wood. Potential Technologies & Strategies Consider salvaged materials such as doors and frames, cabinetry and furniture, and decorative items. MR Credit 4: Recycled Content (2 Points) Intent: To increase demand for building products that incorporate recycled content materials, thereby reducing impacts resulting from extraction and processing of virgin materials. Requirements Use materials with recycled content such that the sum of postconsumer recycled content plus 1/2 of the Pre-consumer content constitutes at least 20%, based on cost, of the total value of the materials in the project. Mechanical, electrical and plumbing components and specialty items such as elevators cannot be included in this calculation, only materials permanently installed in the project can be used. Furniture is included as it is included consistently in MR Credit 3: Materials Reuse through MR Credit 7: Certified Wood. C-9

112 MR Credit 5: Regional Materials (2 Points) Intent: To increase demand for building materials and products that are extracted and manufactured within the region, thereby supporting the use of indigenous resources and reducing the environmental impacts resulting from transportation. Requirements Use building materials or products that have been extracted, harvested or recovered, as well as manufactured, within 500 miles of the project site for a minimum of 20%, based on cost, of the total materials value. Mechanical, electrical and plumbing components and specialty items such as elevators and equipment are not included in this calculation, only materials permanently installed in the project are used. Furniture is included as it is included consistently in MR Credit 3: Materials Reuse through MR Credit 7: Certified Wood. MR Credit 6: Rapidly Renewable Materials (1 Point) Intent: To reduce the use and depletion of finite raw materials and long-cycle renewable materials by replacing them with rapidly renewable materials. Requirements Use rapidly renewable building materials and products for 2.5% of the total value of all building materials and products used in the project, based on cost. Rapidly renewable building materials and products are made from plants that are typically harvested within a 10-year or shorter cycle. MR Credit 7: Certified Wood (1 Point) Intent: To encourage environmentally responsible forest management. Requirements Use a minimum of 50% (based on cost) of wood-based materials and products that are certified in accordance with the Forest Stewardship Council s principles and criteria, for wood building components. These components include at a minimum, structural framing and general dimensional framing, flooring, sub-flooring, wood doors and finishes. Include only materials permanently installed in the project. Wood products purchased for temporary use on the project (e.g., formwork, bracing, scaffolding, sidewalk protection, and guard rails) may be included in the calculation. If any such materials are included, all such materials must be included in the calculation. Potential Technologies & Strategies Establish a project goal for FSC-certified wood products and identify suppliers that can achieve this goal. Indoor Environmental Quality *IEQ Prerequisite 1: Minimum Indoor Air Quality Performance Required Intent: To establish minimum indoor air quality (IAQ) performance to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of the occupants. Requirements Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard , Ventilation for Acceptable Indoor Air Quality AND: CASE 1. Mechanically Ventilated Spaces C-10

113 Mechanical ventilation systems must be designed using the ventilation rate procedure or the applicable local code, whichever is more stringent. *IEQ Prerequisite 2: Environmental Tobacco Smoke (ETS) Control Required Intent: To prevent or minimize exposure of building occupants, indoor surfaces and ventilation air distribution systems to environmental tobacco smoke (ETS). Requirements CASE 1. All Projects OPTION 1 Prohibit smoking in the building. Prohibit on-property smoking within 25-ft. of entries, outdoor air intakes and operable windows. Provide signage to prohibit smoking on the entire property. IEQ Credit 1: Outdoor Air Delivery Monitoring (1 Point) Intent: To provide capacity for ventilation system monitoring to help promote occupant comfort and well-being. Requirements Install permanent monitoring systems to ensure that ventilation systems maintain design minimum requirements. Configure all monitoring equipment to generate an alarm when airflow values or carbon dioxide (CO2) levels vary by 10% or more from the design values via either a building automation system alarm to the building operator or a visual or audible alert to the building occupants AND: CASE 1. Mechanically Ventilated Spaces Monitor CO2 concentrations within all densely occupied spaces (those with a design occupant density of 25 people or more per 1,000-ft. 2 ). CO2 monitors must be between 3 and 6-ft. above the floor. Provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow with an accuracy of plus or minus 15% of the design minimum outdoor air rate, as defined by ASHRAE Standard for mechanical ventilation systems where 20% or more of the design supply airflow serves non-densely occupied spaces. IEQ Credit 4.1: Low-Emitting Materials Adhesives and Sealants (1 Point) Intent: To reduce the quantity of indoor air contaminants that are odorous, irritating and/or harmful to the comfort and well-being of installers and occupants. Requirements All adhesives and sealants used on the interior of the building (i.e., inside of the weatherproofing system and applied on-site) must comply. IEQ Credit 4.2: Low-Emitting Materials Paints and Coatings (1 Point) Intent: To reduce the quantity of indoor air contaminants that are odorous, irritating and/or harmful to the comfort and well-being of installers and occupants. Requirements Paints and coatings used on the interior of the building (i.e., inside of the weatherproofing system and applied onsite) must comply. C-11

114 IEQ Credit 4.3: Low-Emitting Materials Flooring Systems (1 Point) Intent: To reduce the quantity of indoor air contaminants that are odorous, irritating and/or harmful to the comfort and well-being of installers and occupants. OPTION 2 All flooring elements installed in the building interior must meet the testing and product requirements of the California Department of Health Services Standard Practice for the Testing of Volatile Organic Emissions from Various Sources Using Small-Scale Environmental Chambers, including 2004 Addenda. IEQ Credit 6.1: Controllability of Systems Lighting (1 Point) Intent: To provide a high level of lighting system control by individual occupants or groups in multi-occupant spaces (e.g., classrooms and conference areas) and promote their productivity, comfort and well-being. Requirements Provide individual lighting controls for 90% (minimum) of the building occupants to enable adjustments to suit individual task needs and preferences. Provide lighting system controls for all shared multi-occupant spaces to enable adjustments that meet group needs and preferences. Potential Technologies & Strategies Design the building with occupant controls for lighting. Strategies to consider include lighting controls and task lighting. Integrate lighting systems controllability into the overall lighting design, providing ambient and task lighting while managing the overall energy use of the building. IEQ Credit 6.2: Controllability of Systems Thermal Comfort (1 Point) Intent: To provide a high level of thermal comfort system control by individual occupants or groups in multi-occupant spaces (e.g., classrooms or conference areas) and promote their productivity, comfort and well-being. Requirements Provide individual comfort controls for 50% (minimum) of the building occupants to enable adjustments to meet individual needs and preferences. Operable windows may be used in lieu of controls for occupants located 20-ft. inside and 10-ft. to either side of the operable part of a window. The areas of operable window must meet the requirements of ASHRAE Standard paragraph 5.1 Natural Ventilation (with errata but without addenda2). Provide comfort system controls for all shared multi-occupant spaces to enable adjustments that meet group needs and preferences. Conditions for thermal comfort are described in ASHRAE Standard (with errata but without addenda2) and include the primary factors of air temperature, radiant temperature, air speed and humidity. Potential Technologies & Strategies Design the building and systems with comfort controls to allow adjustments to suit individual needs. Individual adjustments may involve individual thermostat controls, local diffusers at floor, desk or overhead levels, control of individual radiant panels or other means integrated into the overall building, thermal comfort systems and energy systems design. Designers should evaluate the closely tied interactions between thermal comfort and acceptable indoor air quality. IEQ Credit 7.1: Thermal Comfort Design (1 Point) C-12

115 Intent: To provide a comfortable thermal environment that promotes occupant productivity and well-being. Requirements Design heating, ventilating and air conditioning (HVAC) systems and the building envelope to meet the requirements of ASHRAE Standard , Thermal Comfort Conditions for Human Occupancy. Potential Technologies & Strategies Design the building envelope and systems with the capability to meet the comfort criteria under expected environmental and use conditions. Evaluate air temperature, radiant temperature, air speed and relative humidity in an integrated fashion, and coordinate these criteria with IEQ Prerequisite 1: Minimum IAQ Performance, IEQ Credit 1: Outdoor Air Delivery Monitoring, and IEQ Credit 2: Increased Ventilation. IEQ Credit 7.2: Thermal Comfort Verification (1 point AND IEQ credit 7.1) Intent: To provide for the assessment of building occupant thermal comfort over time. Requirements Achieve IEQ Credit 7.1: Thermal Comfort Design. Provide a permanent monitoring system to ensure that building performance meets the desired comfort criteria as determined by IEQ Credit 7.1: Thermal Comfort Design. *IEQ Credit 8.1: Daylight and Views Daylight (1 Point) Intent: To provide building occupants with a connection between indoor spaces and the outdoors through the introduction of daylight and views into the regularly occupied areas of the building. OPTION 2. Prescriptive Use side-lighting to achieve a total daylighting zone (the floor area meeting the following requirements) that is at least 75% of all the regularly occupied spaces. Achieve a value, calculated as the product of the visible light transmittance (VLT) and window-to-floor area ratio (WFR) of daylight zone between and The window area included in the calculation must be at least 30 inches above the floor. The ceiling must not obstruct a line in section that joins the window-head to a line on the floor that is parallel to the plane of the window; is twice the height of the window-head above the floor in, distance from the plane of the glass as measured perpendicular to the plane of the glass. Provide sunlight redirection and/or glare control devices to ensure daylight effectiveness. Potential Technologies & Strategies Design the building to maximize interior daylighting. Strategies to consider include building orientation, shallow floor plates, increased building perimeter, exterior and interior permanent shading devices, high-performance glazing, high-ceiling reflectance values; automatic photocellbased controls can help to reduce energy use. *IEQ Credit 8.2: Daylight and Views Views (1 Point) Intent: To provide building occupants a connection to the outdoors through the introduction of daylight and views into the regularly occupied areas of the building. Requirements C-13

116 Achieve a direct line of sight to the outdoor environment via vision glazing between 30 inches and 90 inches above the finish floor for building occupants in 90% of all regularly occupied areas. Determine the area with a direct line of sight by totaling the regularly occupied square footage that meets the following criteria: In plan view, the area is within sight lines drawn from perimeter vision glazing. In section view, a direct sight line can be drawn from the area to perimeter vision glazing. The line of sight may be drawn through interior glazing. For private offices, the entire square footage of the office may be counted if 75% or more of the area has a direct line of sight to perimeter vision glazing. For multi-occupant spaces, the actual square footage with a direct line of sight to perimeter vision glazing is counted. Potential Technologies & Strategies Design the space to maximize daylighting and view opportunities. Strategies to consider include lower partitions, interior shading devices, interior glazing and automatic photocell-based controls. Innovative Design ID Credit 1: Innovation in Design (1 Point) Intent: To provide design teams and projects the opportunity to achieve exceptional performance above the requirements set by the LEED Green Building Rating System and/or innovative performance in Green Building categories not specifically addressed by the LEED Green Building Rating System. Requirements PATH 1. Innovation in Design (1 point) Achieve significant, measurable environmental performance using a strategy not addressed in the LEED 2009 for New Construction and Major Renovations Rating System. ID Credit 2: LEED Accredited Professional (1 Point) Intent: To support and encourage the design integration required by LEED to streamline the application and certification process. Requirements At least 1 principal participant of the project team shall be a LEED Accredited Professional (AP). C-14

117 APPENDIX D LEED 2009 Tower Daylight and Views Calculation Summary

118 D-1

119 APPENDIX E CLT Tower Building Characteristics

120 E.1 Architectural Features a. Area and geometry of the compartments i. Building is 40 m 40 m 1. 51,200 m 2 total building area, including central core, residential units, amenity floor areas/refuge Areas, retail area, and carparks, ii. 27 Residential floors with 1,251 m 2 living area each iii. Each residential floor has 10 open-plan condominium apartment units iv. 3 building amenity floors include the closed-plan Area of Refuge and the open-plan fitness areas/other amenities v. Closed-plan retail areas are located along the perimeter of the Ground floor vi. Two carpark levels have an open-plan design b. Floor-to-ceiling height: 3m c. Terrace roof parapet height: 3m d. Exterior balcony: 2.5m wide around the perimeter of the building e. Ceiling configuration: Exposed CLT, flat f. Interior finish flammability i. Ceilings: 1. Exposed CLT with a 2-hr fire rating 2. Lightweight concrete at the three amenity floors ii. Interior walls: 1. Exposed CLT: Bedrooms and Living Rooms 2. Unexposed CLT (encapsulated with gypsum for a 3-hr fire rating): Kitchens iii. Floors: 1. CLT covered with 55mm lightweight concrete 2. Lightweight concrete at the three amenity floors g. Interior thermodynamic properties i. Thermal conductivity ii. Specific heat iii. Density h. Construction materials i. Carpark construction: Precast concrete ii. Columns and beams: Glulam iii. Floors/Ceilings: CLT 1. Wood Species: 2. Moisture Content: i. Interior walls: encapsulated CLT ii. Central core: reinforced concrete shear walls iii. Exterior walls: 3. Separation distance: 2m to adjacent properties 4. Window walls with spectrally selective coated glazing E-1

121 a. Window wall façade does not carry any structural load from the building, other than its own dead weight (non-load bearing) b. Generally designed with extruded aluminum framing members typically infilled with glass, providing excellent daylighting, with spandrel infill panels at the floor levels to conceal the framing connections 5. Exterior wall assembly infill area includes: a. Aluminum composite material (ACM) panel system i. FR core ii. Thermally broken system b. Foam Insulation i. Phenolic c. Wall assembly compliant with: i. NFPA 285 ii. ASTM 119 2hr-rated wall assembly i. Properties of walls, partitions, floors, and ceilings i. 1-hr. fire-resistance rated smoke barrier elevator lobby j. Position, size, and quantity of door/window openings i. Vestibule entrance area at Ground Floor: 1. Floor-to-ceiling glass doors and windows 10m long ii. Ancillary ground floor exits 1. Floor-to-ceiling glass doors and windows 1m long iii. Remaining Ground Floor perimeter: 1. Floor-to-ceiling glass windows iv. Residential Floor Units: 1. Unit 1 and Unit 10 window area, 762 mm (2-6 ) above floor 1,828 mm (6-0 ) high a. 39m 2 each unit per floor b. 52 total units required 2. Unit 2 and Unit 9 window area a. 26m 2 each unit per floor b. 52 total units required 3. Unit 3 and Unit 8 window area a. 46m 2 each unit per floor b. 52 total units required 4. Unit 4, Unit 5, Unit 6, and Unit 7 window area a. 27m 2 each unit per floor b. 104 total units required v. Building Amenity Floors 1. Area of Refuge a. No window areas E-2

122 2. Amenity Floor Areas a. Floor-to-ceiling glass windows along perimeter of building vi. Carpark levels 1. L1 level a. No exterior windows or doors 2. L2 level a. No exterior windows b. One each floor-to-ceiling entrance and exit openings k. Configuration and location of hidden voids i. Balloon framing eliminates hidden voids in structural connections ii. Trash/recycle chutes connected to the basement for disposal are designed on each level l. 93m tall mixed-use building i. Number of stories above grade: Includes access to Open Space Roof Area ii. Number of stories below grade: 2 m. Location of the building on the site relative to property lines: 2m each side n. Interconnections between compartments: i. Each residential unit is separated by a 3-hr rated demising wall ii. Residential units are separated from the corridor areas by a 3-hr rated demising wall iii. Retail areas on the ground floor are separated by a 3-hr fire rated demising wall iv. The Area of Refuge is separated from the corridor area on the Building Amenity floors by a 3-hr fire rated demising wall o. Relationship of hazards to vulnerable points E.2 Structural Components a. Location, size, and construction material of load-bearing elements: i. Precast concrete carpark structure ii. Columns and beams: Glulam 1. Column sizes: a. 3 rd floor 12 th floor: 610 mm 610 mm (24 24 ) b. 13 th floor - 22 nd floor: 356 mm 457 mm (14 x 18 ) c. 23 rd floor 32 nd floor: 241 mm 305 mm ( ) iii. Floors and ceilings: 1. CLT - Not exposed a. 3 rd floor 12 th floor (except 9 th floor): 254 mm (10 ) thick b. 13 th floor - 22 nd floor (except 17 th floor): 203 mm (8 ) thick c. 23 rd floor 32 nd floor (except 25 th floor): 140 mm (5.5 ) thick iv. Floor and ceilings: 1. Concrete exposed E-3

123 a. 9 th, 17 th, 25 th floors: mm (6 ) thick v. Roof Panels: CLT 1. Not exposed CLT a. 5 plies: 2.5m 10m 95mm thick vi. Central core: reinforced concrete shear walls 1. 3 rd floor 12 th floor: 508 mm (20 ) thick th floor - 22 nd floor: 406 (16 ) thick rd floor 32 nd floor: 305 (12 ) thick b. Properties of structural elements: i. Strength ii. Thermal conductivity iii. Specific heat iv. Reinforcement v. Characteristic of connections 1. Balloon framing a. Concealed connections c. Protection material characteristics: i. Thickness ii. Thermal conductivity iii. Specific heat d. Design structural loads E.3 Fire Load a. Retail Area i. Furnishings ii. Office supplies iii. Displays iv. Wall linings v. Carpeting b. Residential Area i. Wall linings ii. Furnishings iii. Cooking equipment iv. Laundry dryer lint v. Carpeting c. Amenity Floor Area i. Equipment (floor mats, treadmill tracks) ii. Paper towels, etc. E.4 Egress Components a. The main entrance to the building is located on the Ground floor b. Ground floor is assigned as the exit discharge level c. Retail areas have direct access to the outside d. Evacuation strategy is based on self-evacuation using 4 elevators E-4

124 e. One service elevator to be used by firefighters during an emergency f. One exit stairwell, connecting all levels, to discharge on the Ground level E.5 Fire Protection Systems a. Communication systems i. Emergency voice/alarm communication system in elevator groups, exit stairway, each floor, and areas of refuge ii. Elevators and areas of refuge are equipped with two-way communication systems b. Alarm system: i. Manual fire alarm boxes at entrance to each exit, red in color c. Detection systems i. Smoke detectors in mechanical/electrical rooms, elevator lobbies, main exhaust and return of air ventilation, and each connection to a vertical duct d. Notification systems i. Visible 1. Strobes in public and common areas, e.g. floors 1, 9, 17, and 25 ii. Audible 2. Horns in every occupied space within the building e. Smoke control: i. HVAC systems designed separately for each floor to minimize smoke migration ii. Pressurized stairwell to prevent the stack effect f. Suppression systems i. Automatic sprinkler system 1. All patios with CLT ceilings are protected by a sprinkler system installed through concealed, internal raceways ii. Portable fire extinguishers placed throughout the floor corridors and in each unit g. Gas supply shut-off h. Emergency lighting E.6 Building Services and Processes a. Location, capacity, and characteristics of ventilation equipment i. Mechanical ventilation 1. Zoned and Located on 9 th and 24 th Floor levels 2. Continually operating ii. Summer/ Winter differences 3. Summer Cooling: 22 C (72 F) with 45% humidity 4. Winter Heating: 20 C (68 F) with 35% humidity b. Effects on the ambient environment c. Location and capacity of electrical distribution equipment d. Potential ignition sources E-5

125 E.7 Operational Characteristics a. Expected occupancy times i. Retail Areas 1. Sundays: 1:00 p.m. 6:00 p.m. 2. Mondays: Closed 3. Tuesdays Thursdays: 10:00 a.m. 6:00 p.m. 4. Fridays Saturdays: 10:00 a.m. 8:00 p.m. ii. Residential Units 1. Permanent Occupants a. Sundays: 7:00 p.m. 9:00 a.m. b. Mondays - Fridays: 6:00 p.m. 7:00 a.m. c. Saturdays: 1:00 a.m. 11:00 a.m., and 3:00 p.m. 8:00 p.m. 2. Transient Occupants a. Sundays: 7:00 p.m. 1:30 p.m. b. Mondays - Fridays: 9:00 p.m. 7:00 a.m. c. Saturdays: 1:00 a.m. 11:00 a.m., and 3:00 p.m. 8:00 p.m. iii. Amenity Areas 1. Sundays: 11:00 a.m. 6:00 p.m. 2. Mondays Fridays: 5:00 a.m. 10:00 p.m. 3. Saturdays: 7:00 a.m. 7:00 p.m. E.8 Fire Department Response Characteristics a. Response time of fire fighters i. Charlotte Fire Station 04 is located 2 blocks away ii. Fire Response Area includes 2.77 km 2 (685 acres) with a perimeter of 15,232 m (49,973 ) b. Accessibility for fire appliances i. Emergency vehicles: 1. Clear access on West and South building elevations respectively ii. Fire hydrate is located directly in front on North College Street 1. Connected to pubic water main m 2 ( GPM) available flow bar ( psi) hydrant pressure iii. Vestibule area provided at entrance for easier fire hose access to the building c. Fire fighter access within the building i. Vestibule area provided at entrance rather than revolving door d. Equipment i. Fire Department Connection (FDC) located on the South elevation of building ii. Standpipe located in the stairwell with access at each floor level E.9 Environmental Factors a. Tower located in Charlotte, North Carolina, USA E-6

126 i. Climate Zone 3: ASHRAE 90.1 [24] Prescriptive Requirements b. Elevation 221m (725 ) above sea level with a humid, sub-tropic climate E-7