Canadian Code Requirements - Fire NBC Division A and Division B (Part 3)

Transcription

1 NRC - Institute for Research in Construction Canadian Code Requirements - Fire NBC Division A and Division B (Part 3) Fire Research Program June 13 th, 2011 NRC Institute for Research in Construction

2 Outline General Process for Code Compliance Issues Relating to NBC Division B Part 3 for Mid/High-Rise (Larger) Combustible Buildings Objectives and Functional Requirements NBC Division B Part 3 Satisfying the Objectives and Functional Requirements Acceptable Solutions Alternative Solutions Sources and Technical Information Canadian Studies and Information NRC Institute for Research in Construction 2

3 Code Compliance Compliance with NBC 2010 shall be achieved by complying with the applicable acceptable solutions in Division B using alternative solutions (Division A) NRC Institute for Research in Construction 3

4 Alternative Solution - Compliance (b) Compliance achieved using alternative solutions that will achieve at least the minimum level of performance required by Division B in the areas defined by the objectives and functional statements attributed to the applicable acceptable solutions. (Note: Similar to equivalency in previous NBC editions.) NRC Institute for Research in Construction 4

5 Code Analysis for LWF and CLT Applicable Solution (NBC Division B) Part 3 Fire protection, Occupant Safety and Accessibility Combustible construction Non combustible Objectives and Functional Statements (NBC Division A) Attribution tables for Part 3 Compliance Path Examples LWF (1) CLT (2) Alternative solution to non combustible construction for mid /high rise based on low rise Alternative solution to non combustible construction for mid /high rise Part 4 Structural Design Attribution tables for Part 4 Demonstrate compliance to Part 4 (CSA O86) Part 5 Environmental Attribution tables for Part 5 Separation (1) LWF Light wood frame (2) CLT Cross laminated timber Demonstrate compliance to Part 5 Demonstrate compliance to Part 4 (CSA O86) Demonstrate compliance to Part 5 NRC Institute for Research in Construction 5

6 Code Objectives Describe the overall goals that the Code s requirements are intended to achieve. Each Code requirement is linked to one or more objectives: 4 main Objectives OS Safety OH Health OA Accessibility OP Fire and Structural Protection of Buildings NRC Institute for Research in Construction 6

7 Functional Statement Objective Pairs define Area of Performance Building Envelope Environmental Separator Applicable provisions FS O Functional Statement Link Objective To <function> What/from So that People/building Not <harmed> due to (1) F80 OH1.1 To resist deterioration resulting from expected service conditions F80 OH1.2 To resist deterioration resulting from expected service conditions So that So that A person is not exposed to an unacceptable risk of illness due to inadequate indoor air quality A person is not exposed to an unacceptable risk of illness due to inadequate thermal comfort F80 OS2.3 To resist deterioration resulting from expected service conditions So that A person is not exposed to an unacceptable risk of injury due to damage or deterioration of the building elements NRC Institute for Research in Construction 7

8 Functional Statement Objective Pairs - define Area of Performance Fire Protection Applicable provisions FS O Functional Statement Link Objective To <function> What/from So that People/building Not <harmed> due to Noncombustible Construction (to limit severity of fire effects to unacceptable risk to persons/building) F02 OS1.2 To limit the severity and effects of fire and explosions So that A person is not exposed to an unacceptable risk due to fire or explosion impacting area beyond its point of origin F02 OP1.2 To limit the severity and effects of fire and explosions So that The building is not exposed to an unacceptable risk due to fire and explosion impacting area beyond its point of origin NRC Institute for Research in Construction 8

9 Performance Level The Alternative Solution must provide at least the minimum level of performance required for the Acceptable Solution it is replacing. Challenge for Wood and Wood-Hybrid Mid/High-Rise Buildings The combustible solution must provide at least the minimum level of performance required for the noncombustible solution it is replacing. NRC Institute for Research in Construction 9

10 Ensuring Whole Building Performance Approach Review of Performance Requirements NRC Institute for Research in Construction 10

11 Issues Relating to NBC Division B Part 3 for Mid/High-Rise Combustible Buildings Bigger height Larger areas Combustible structural systems Response and evacuation Challenging geometries and design details (3-D joints, etc.) Innovative products (CLTs, ) Others? NRC Institute for Research in Construction 11

12 Objective-Based Codes NBC Part 3 Fire Safety Objectives OS1 Safety Fire Safety to limit the probability that a person in or adjacent to the building will be exposed to an unacceptable risk of injury due to fire caused by: OS1.1 fire or explosion occurring OS1.2 fire or explosion impacting areas beyond its point of origin OS1.3 collapse of physical elements due to fire or explosion OS1.4 fire safety systems failing due to function as expected OS1.5 Person being delayed in or impeded from moving to a safe place during a fire emergency NRC Institute for Research in Construction 12

13 Objective-Based Codes NBC Part 3 Fire Safety Objectives OP1 Fire and Structural Protection of Buildings Fire Protection of Buildings to limit the probability that the building will be exposed to an unacceptable risk of damage due to fire caused by: OP 1.1 fire or explosion occurring OP 1.2 fire or explosion impacting areas beyond its point of origin OP 1.3 collapse of physical elements due to fire or explosion OP 1.4 fire safety systems failing due to function as expected NRC Institute for Research in Construction 13

14 Objective-Based Codes NBC Part 3 Fire Safety Objectives OP3 Fire and Structural Protection of Buildings Protection of Adjacent Buildings from Fire to limit the probability that adjacent buildings will be exposed to an unacceptable risk of damage due to fire caused by: OP 3.1 fire or explosion impacting areas beyond the building of origin NRC Institute for Research in Construction 14

15 Objective-Based Codes NBC Part 3 Fire Safety Functional Statements F01 To minimize the risk of accidental ignition F02 To limit the severity and effects of fire or explosions F03 To retard the effects of fire on areas beyond its point of origin F04 To retard failure or collapse due to the effects of fire F05 To retard the effects of fire on emergency egress facilities F06 To retard the effects of fire on facilities for notification, suppression and emergency response F10 To facilitate the timely movement of persons to a safe place in an emergency F11 To notify persons, in a timely manner, of the need to take action in an emergency F12 To facilitate emergency response F13 To notify emergency responders, in a timely manner, of the need to take action in an emergency NRC Institute for Research in Construction 15

16 Functional Statement Objective Pairs Applicable provisions Fire Protection FS O Functional Statement Link Objective Noncombustible Construction (to limit severity of fire effects to risk to persons/building) F02 OS1.2 To limit the severity and effects of fire and explosions F02 OP1.2 To limit the severity and effects of fire and explosions So that So that A person is not exposed to an unacceptable risk due to fire or explosion impacting area beyond its point of origin The building is not exposed to an unacceptable risk due to fire and explosion impacting area beyond its point of origin Fire Resistance Ratings (to retard failure/collapse effects to risk to persons/building) F04 OS1.3 To retard the failure or collapse due to effects of fire F04 OP1.3 To retard the failure or collapse due to effects of fire So that So that A person is not exposed to an unacceptable risk due to collapse of physical elements due to a fire or explosion The building is not exposed to an unacceptable risk due to collapse of physical elements due to a fire or explosion Sprinklered Throughout (to limit severity and retard failure/ collapse effects to risk to persons/building) F02 F04 F02 F04 OS1.2 OS1.3 OP1.2 OP1.3 To limit and retard the failure or collapse due to effects of fire To limit and retard the failure or collapse due to effects of fire NRC Institute for Research in Construction So that So that A person is not exposed to an unacceptable risk due to fire or explosion impacting area beyond its point of origin and collapse The building is not exposed to an unacceptable risk due to collapse of physical elements due to a fire or explosion. 16

17 Satisfying the Objectives and Functional Requirements Different ways: NBC Division B - Acceptable Solutions Alternative Solutions 1. Equivalency with the acceptable solutions 2. Full fire risk assessment evaluation NRC Institute for Research in Construction 17

18 Objective-Based Codes Division B - Acceptable Solutions Part 3 Fire Protection, Occupant Safety and Accessibility 3.2 Building Fire Safety Building Size & Construction Relative to Occupancy Examples of Building Classification Group C Residential Group D Business and personal services Group E Mercantile Group A Division 2 Assemblies NRC Institute for Research in Construction 18

19 Objective-Based Codes Division B - Acceptable Solutions Group C Residential Classification Group C (Residential) Number of storeys Maximum area of the building Construction type Fire resistance Sprinklers Any Height Any area Non combustible Floors 2 h FRR Required Mezzanine 1 h FRR throughout Load bearing walls, columns and arches more FRR of supporting assemblies Group C (Residential) Up to 6 storeys For 2 Storeys unlimited area For 3 Storeys, max m 2 For 4 Storeys, max m 2 For 5 Storeys, max m 2 For 6 Storeys, max m 2 Non combustible Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout Group C (Residential) Up to 4 storeys For 1 Storeys, max m 2 For 2 Storeys, max m 2 For 3 Storeys, max m 2 For 4 Storeys, max m 2 Combustible or non combustible or a combination Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout NRC Institute for Research in Construction 19

20 Objective-Based Codes Division B - Acceptable Solutions Group D Business and personal services Classification Number of storeys Maximum area of the building Construction type Fire resistance Sprinklers Group D (office, business) Any Height Any area Noncombustible Floors 2 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout Group D (office, business) Up to 6 storeys Area depends on height and access: e.g. for 6 Storey building, max m 2 (facing 1 street), 3000 m 2 (facing 2 streets), 3600 m 2 (facing 3 streets) Noncombustible Floors 1 h FRR Mezzanine 1 h FRR Roof assemblies 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Not required Group D (office, business) Up to 6 storeys Area depends on height and access: e.g., for 5 Storeys, max m 2 e.g., for 6 Storeys, max m 2 Noncombustible Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout Group D (office, business) Up to 4 storeys Max. area of 3600 m 2 Combustible or noncombustible or a combination Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout NRC Institute for Research in Construction 20

21 Objective-Based Codes Division B - Acceptable Solutions Group E Mercantile Classification Group E (Mercantile) Number of storeys Maximum area of the building Construction type Fire resistance Sprinklers Any Height Any area Non combustible Floors 2 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout Group E (Mercantile) Up to 4 storeys Max. area of 1800 m 2 Combustible or non combustible or a combination Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout NRC Institute for Research in Construction 21

22 Objective-Based Codes Division B - Acceptable Solutions Group A Division 2 Assemblies Classification Number of storeys Maximum area of the building Construction type Fire resistance Sprinklers Group A Division 2 (assembly) Group A Division 2 (assembly) Any Height Any area Non combustible Floors 2 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Up to 6 storeys Any area Non combustible Floors 1 h FRR Mezzanine 1 h FRR Load bearing walls, columns and arches more FRR of supporting assemblies Required throughout Required throughout Group A Division 2 (assembly) Up to 2 storeys For 1 Storey building, max.: 4800 m 2 For 2 Storey building, max.: 2400 m 2 Combustible or non combustible or a combination Floors 45 min FRR (if combustible) Mezzanine 45 min FRR (if combustible) Load bearing walls, columns and arches supporting assemblies 45 min FRR or be of non combustible construction Required throughout NRC Institute for Research in Construction 22

23 Objective-Based Codes Division B - Acceptable Solutions Noncombustible Construction Limit fire size, duration and severity by controlling amount of fuel available to the fire Materials that pass CAN/ULC-S114 NRC Institute for Research in Construction 23

24 Objective-Based Codes Division B - Acceptable Solutions Noncombustible Construction specifies that buildings required to be of noncombustible construction be constructed using noncombustible materials to provide exceptions/limits for use of combustible construction materials o Gypsum board, combustible roofing materials, combustible flooring elements, combustible interior finishes, combustible elements in partitions, among others permits combustible materials in exterior non-load-bearing wall assemblies if CAN/ULC-S134 requirements are met Combustible structural materials not allowed in fire resistive assemblies in non-combustible buildings NRC Institute for Research in Construction 24

25 Objective-Based Codes Alternative Solutions - Equivalency Noncombustible versus combustible construction Issues o Need to demonstrate that fire severity for buildings with combustible structural systems is similar to that of buildings with noncombustible structural systems o Need to demonstrate that fire spread for combustible exterior wall assemblies is not an issue of concern NRC Institute for Research in Construction 25

26 Objective-Based Codes Alternative Solutions - Equivalency Noncombustible versus combustible construction Potential Solutions BC Equivalent Solution o Limits floor area such that total floor area of a mid-rise building is equivalent to that for a 4-storey building using combustible construction Other Possible Solutions o Use noncombustible thermal barriers to protect combustible structural materials to limit initial contribution to fire o Area requirements for noncombustible construction may also be applied in the case of combustible construction NRC Institute for Research in Construction 26

27 Objective-Based Codes Alternative Solutions Equivalency Noncombustible versus combustible construction Exterior Wall Assemblies Potential Solutions Noncombustible wall assemblies curtain walls - BC Option 1 o Issues durability of connection to floor assembly and failure of connection in fire Combustible wood frame wall assemblies BC Option 2 o Interior protected by thermal barrier o Exterior protected using noncombustible or limited combustible material o Passes CAN/ULC S134 Combustible wood frame wall assemblies BC Option 3 o Same as Option 2 except exterior protected by fire retardant panels o Test using CAN/ULC S134 NRC Institute for Research in Construction 27

28 Objective-Based Codes Alternative Solutions - Equivalency Fire Resistance Ratings Issues Need to demonstrate that the required ratings are satisfied when using combustible structural construction systems Fire Resistance Ratings Potential Solutions BC Equivalent Solution Use existing assemblies meeting the required FRR Other Solutions - Further test data for new innovative products (e.g., CLT) or where data is not available (e.g., assemblies suggested for earthquake but with no existing FRR) NRC Institute for Research in Construction 28

29 Objective-Based Codes Alternative Solutions - Equivalency Sprinkler Protection Issues Ensure adequate application of NFPA 13 requirements for seismic, concealed spaces, etc. In the long term, ensure availability of data on the functionality and reliability of sprinkler and other systems for use in fire risk assessment NRC Institute for Research in Construction 29

30 Summary Noncombustible versus Combustible Construction Develop Solutions to Limit Fire Severity Develop Solutions to Limit Fire Spread on Exterior Walls Fire Resistance Ratings Develop Solutions to meet fire resistance ratings Sprinkler Protection Review NFPA 13 requirements to ensure adequate application NRC Institute for Research in Construction 30

31 Other Issues Needing Attention Aging population and mobility impairment affects ability of occupants to self-evacuate? Fire stops and fire blocking? Direct ignition of combustible structural systems? Fire during construction? Others? NRC Institute for Research in Construction 31

32 Objective-Based Codes Alternative Solutions Risk Assessment Long term full performance-based design solution Items to consider in a full fire risk assessment o Design fire scenarios and design fires o Smoke and fire spread o Active fire protection o Response and evacuation of occupants o Fire fighting response and rescue o Tenability analysis o Structural fire resistance and compartmentation o Risk evaluation for a reference design option vs. other design options NRC Institute for Research in Construction 32

33 Sources and Technical Information New Zealand and Australia Structural Timber Innovation Company New pre-fabricated LVL and Glulam timber structural systems for multi-storey commercial and industrial buildings: Fire research (fire resistance, connection, etc.) is carried out at the University of Canterbury Other research topics include: o Sound transmission o Impact insulation class rating o Energy and sustainable building information o Durability information and specifications o Major work in the structural and seismic area NRC Institute for Research in Construction 33

34 Sources and Technical Information Europe FireInTimber (Fire resistance of Innovative Timber structure) an European project of the WoodWisdom Net Load-bearing timber structures and lightweight structures during fire exposure Connections, joints, penetrations and fire stops European guidelines on fire safety in timber buildings NRC Institute for Research in Construction 34

35 Sources and Technical Information UK TF2000 timber-frame 6-storey Compartment fire to test fire resistance o Structural integrity o Compartmentation NRC Institute for Research in Construction 35

36 Sources and Technical Information Japan Timber-based hybrid buildings (U of Tokyo, BRI) o Principle of performance evaluation o Guideline of structural and fireproof design Italian/Japanese fire studies on timber buildings o Shaking table test o Then fire test NRC Institute for Research in Construction 36

37 Canadian Studies and Information BC and Quebec Solutions/Experiences NRC/CWC/FPInnovations Joint Research Project (to be addressed tomorrow) NRC Institute for Research in Construction 37

38 Discussion Thank-you NRC Institute for Research in Construction

39 Fire Performance of Heavy Timber Connections George Hadjisophocleous and Lei Peng Industrial Research Chair in Fire Safety Engineering Department of Civil and Environmental Engineering

40 Outline Background Objectives Description of test facility Description of tests Results Conclusions NEWBuildS Theme 2 Research Exchange, June

41 Background Connections in heavy timber buildings: weak link Motivation: no design methods available in the National Building Code of Canada (NBCC); need of new and simplified fire resistance calculation approaches. NEWBuildS Theme 2 Research Exchange, June

42 Objectives Study the effects of different factors, i.e. wood side member thickness, diameter and number of fasteners, load ratio and protection on the fire performance of timber connections; Develop simple calculation methods that can be used to predict the fire resistance ratings of timber connections. NEWBuildS Theme 2 Research Exchange, June

43 Scope Experimental: Wood Steel Wood (WSW) bolted connections & Steel Wood Steel (SWS) bolted connections, loaded in tension Correlations: WWW and WSW connections with either bolts or dowels; SWS bolted connections. Wood Wood Wood Wood Steel Wood Steel Wood Steel NEWBuildS Theme 2 Research Exchange, June

44 Methodology Experimental Program: Fire resistance tests of bolted WSW and SWS connections Calculation Model: Heat transfer analysis (Finite Element Model) Analytical structural model Correlations: Simplified calculation methods NEWBuildS Theme 2 Research Exchange, June

45 Experimental Program Facilities (furnace, load frame, burners, jack, load cell, LVDTs) NEWBuildS Theme 2 Research Exchange, June

46 The Furnace NEWBuildS Theme 2 Research Exchange, June

47 WSW Specimens 5 groups, including 16 specimens: 14 unprotected 2 protected (5/8 Type X gypsum; 2 layer of ½ plywood) Side wood thickness (38 mm 80 mm); load ratio (10% 30%); bolt diameter ( 12.7 mm & 19.1 mm) NEWBuildS Theme 2 Research Exchange, June

48 SWS Specimens 2 groups, including 6 specimens: 4 unprotected 2 protected (5/8 Type X gypsum; 2 mm intumescent paint) Wood thickness (80 mm & 130 mm); load ratio (10% 30%); bolt diameter (12.7mm & 19.1 mm) NEWBuildS Theme 2 Research Exchange, June

49 Fire Resistance Tests Pre load the specimen in tension for about 30 minutes Start the standard fire (CAN/ULC S101) Stop testing when the applied load could not be withstood. NEWBuildS Theme 2 Research Exchange, June

50 Fire Resistance Test NEWBuildS Theme 2 Research Exchange, June

51 Fire Resistance Tests NEWBuildS Theme 2 Research Exchange, June

52 Fire Resistance Tests NEWBuildS Theme 2 Research Exchange, June

53 Results (WSW) Figure: failure time vs. load ratio Effects of load ratio, wood side member thickness (t1), and bolt diameter (d) NEWBuildS Theme 2 Research Exchange, June

54 Failure Mode (WSW) (a): extensive hole elongation; (b): complete cutting through wood members; (c): splitting of wood members; (d): tear out of edge material. NEWBuildS Theme 2 Research Exchange, June

55 Results (SWS) Figure: failure time vs. load ratio Effects of load ratio, wood member thickness (t2), and protection NEWBuildS Theme 2 Research Exchange, June

56 Failure Mode (SWS) (a): extensive hole elongation; (b): complete cuttingthrough wood members; (c): splitting of wood members; (d): bending of bolts. NEWBuildS Theme 2 Research Exchange, June

57 Summary The effects of wood member thickness, load ratio, diameter and number of fasteners on the fire performance of timber connections were successfully revealed; The fire resistance ratings of all the tested WSW bolted connections with no protection were less than 45 minutes, a target ratings for Canadian code compliance; The fire resistance ratings of all the tested SWS bolted connections with no protection were less than 25 minutes; The improvement of the fire resistance rating for one layer of 5/8 Type X gypsum board and a double layer of ½ plywood, is 30 minutes and 15 minutes, respectively. NEWBuildS Theme 2 Research Exchange, June

58 Calculation Models Numerical heat transfer model: Finite element program: ABAQUS/Standard Structural analytical model: Calculated temperature distribution (using the heat transfer mode) Embedment reduction method Simplified equations: Correlations based on existing data NEWBuildS Theme 2 Research Exchange, June

59 Heat Transfer Analysis An example: ¼of a WSW connection is modeled. NEWBuildS Theme 2 Research Exchange, June

60 Heat Transfer Analysis Temperature contours NEWBuildS Theme 2 Research Exchange, June

61 Heat Transfer Analysis Residual wood NEWBuildS Theme 2 Research Exchange, June

62 Heat Transfer Analysis Residual wood NEWBuildS Theme 2 Research Exchange, June

63 Heat Transfer Analysis Temperature comparison NEWBuildS Theme 2 Research Exchange, June

64 Heat Transfer Analysis Temperature comparison NEWBuildS Theme 2 Research Exchange, June

65 Structural Model Temperature distribution with in the specimen based on the 3 D heat transfer model Embedment Reduction Method: Integration of the temperature based embedding strength along the bolt length; Two approaches under the embedment reduction method (Noren s approach & Moss approach) Comparison of Noren s approach & Moss approach with test results NEWBuildS Theme 2 Research Exchange, June

66 Structural Model WSW connections as example: Noren s Approach is more accurate. NEWBuildS Theme 2 Research Exchange, June

67 Simple Calculation Method Proposed equation: t f M ( t1 / )(1 ( d / t1) N ) non-dimensionalized: ln(1 t*) M ln( ) Nln( d*) where: t* t / ( t / ); R / R ; d* d / t f 1 f 0 1 t f = failure time; t 1 = wood side member thickness; R f = applied load in fire test; R 0 = load capacity at ambient; = charring rate; η= load ratio; d = fastener diameter.

68 Correlation (WWW & WSW) M and N are two factors, which need to be determined. Curve fitting, using the least squares method to determine M and N as: M = and N = for bolted WWW and WSW; M = and N = for doweled WWW and WSW. NEWBuildS Theme 2 Research Exchange, June

69 Correlation (WWW & WSW) Almost within the ±15% envelope NEWBuildS Theme 2 Research Exchange, June

70 Correlation (SWS) Correlation results: tf ln( ) t2 NEWBuildS Theme 2 Research Exchange, June

71 Correlation (SWS) Almost with in the ± 10% envelope NEWBuildS Theme 2 Research Exchange, June

72 Protected Connections Additive method (adding the additive fire resistance ratings of protective membranes to the fire resistance ratings of unprotected timber connections): t t t f,protected a f t f is the fire resistance rating of unprotected timber connections( calculated using the correlation equations); t a is the time assigned to different types of protective membranes (30 minutes for a single layer of 5/8 Type X gypsum board and 15 minutes for a double layer of ½ plywood panels) NEWBuildS Theme 2 Research Exchange, June

73 Conclusions The fire performance of bolted WSW and SWS timber connections were studied experimentally, and useful knowledge and information was generated for the development of calculation models; The heat transfer model and the analytical structural model were verified to be able to calculate the temperature distribution within the timber connection and to assess the strength of the timber connection at elevated temperatures; The proposed correlations form a basic design tool for evaluating the fire performance of unprotected WWW, WSW and SWS timber connections, and the additive method provides an approach to assess the fire performance of timber connections with protective membranes. NEWBuildS Theme 2 Research Exchange, June

74 i b k Institute of Structural Engineering Fire design concepts for tall timber buildings Andrea Frangi ETH Zurich Institute of Structural Engineering NEWBuildS Research Exchange, Hybrid Building Systems Ottawa, June 13, 2011 Datum

75 Tall timber buildings 10 Storey Residential 30 m 20 Storey Residential 60 m General Sherman Tree Sakyamuni Pagoda (> 3000 years old) (circa 1000 years old) 67 m 83.4 m Great Pyramid of Khufu at Giza 144 m Tallest Tree ever discovered 150 m Introduction

76 Tall timber buildings The term timber building concerns mixed constructions, with most of the structure made of timber Tall buildings (Swiss fire regulations): buildings with a total height H > 25 m or with the top floor located at the height h > 22 m above the level of the terrain used by the fire brigade h>22m H>25m Introduction

77 Use of timber as building material Combustible building materials like timber burn on their surface, release energy and thus contribute to fire propagation and the development of smoke in case of fire The main precondition for the use of wood in buildings is adequate fire safety The combustibility of wood is one of the main reasons for most building codes to strongly limit the use of timber as a building material and in particular of the number of storeys of timber buildings Introduction

78 Use of timber as building material Many countries have liberalized the use of timber for multistorey medium-rise buildings based on results of many research projects Example: new Swiss fire regulations (2003) allow the use of timber structures in multistorey residential buildings up to 6 storeys Tall timber buildings are not allowed mostly worldwide Introduction

79 Fire safety engineering Fire safety objectives Life safety (occupants and fire brigade) Safety of neighbors and their goods Limitation of financial loss (building and content) Protection of the environment Fire safety measures Structural: compartmentation, fire resistance requirements Technical: sprinkler, smoke detection, alarm systems, smoke evacuation systems Organisational: fire brigade, safety official, instruction, house keeping Fire safety concept for tall timber buildings

80 Fire requirements for structural safety concept Swiss fire regulations (2003) Storeys Tall buildings load-bearing elements - Design for normal condition R30 R60 R60/EI30(nbb) R60(nbb) R90(nbb) separating elements EI30 EI30 EI30 EI60 EI60/EI30(nbb) EI60(nbb) EI90(nbb) Timber structures allowed Timber structures not allowed NB: (nbb) means noncombustible material Fire safety concept for tall timber buildings

81 Fire safety concept for medium-rise buildings Fire safety objective Occupants can leave the building or can be evacuated by the fire brigades in case of fire Requirements on building elements Fire regulations recognize that the fire safety objective adopted for medium-rise residential buildings can be achieved with the given requirements despite the combustibility of the structural material used Fire safety concept for tall timber buildings

82 Fire safety concept for tall buildings Fire scenario Occupants located on the upper part of the building need more time to leave the building in case of fire Fire brigade also needs more time to reach and fight the fire Evacuation of the occupants may not be possible by alternative routes or by rescue teams Fire may not be extinguished and continues until all combustible material in the fire compartment has burned Fire safety concept for tall timber buildings

83 Fire safety concept for tall buildings Fire safety objective Occupants shall survive a full burn-out of the fire compartment while remaining in another part of the building Requirements on building elements Separating building elements shall be designed in a way to sustain a full burn-out, thus preventing an uncontrolled fire spread to other parts of the building during the whole duration of the fire Load-bearing building elements shall be designed in a way to prevent the structural collapse for a full burn-out without any intervention of the fire brigade Fire safety concept for tall timber buildings

84 Fire safety concept for tall buildings What are the main differences between medium-rise and tall buildings with regard to fire safety? Type of building Evacuation of people during fire Fire spread to other parts of building Building collapse Medium-rise buildings feasible accepted after defined period of time accepted after defined period of time Tall buildings aggravated, stay in safe place until burn-out not accepted not accepted Fire safety concept for tall timber buildings

85 Fire safety concept for tall buildings Building encapsulation Protection of structural timber elements from fire for the whole time of fire duration by noncombustible material (gypsum plasterboards) Composite elements Timber-concrete composite slabs Use of technical measures (sprinkler, etc.) Fire safety concept for tall timber buildings

86 Experimental investigations on fire safety concepts under natural fire conditions Swiss Expo02 temporary hotels 6 full scale tests Objectives Efficiency of different fire safety concepts (structural, technical) Fire spread inside and outside the room hotel Influence of combustible surfaces in room hotel Efficiency of automatic extinguishing systems

87 Hotel Modules Four hotel modules (H1, H2, G1 and G2) manufactured in shop as light timber frame construction Identical in its basic construction and dimensions Different interior room linings of walls and ceiling Modules H1 and H2: combustible wood panels (OSB) Modules G1 and G2: non combustible gypsum plasterboards Insulating batts in the cavities of the light timber frame assemblies: Pavatherm boards based on 100% wood fibres Natural fire tests

88 Hotel Modules Dimensions: length 6.6 m; width 3.1 m; and height 2.8 m Window opening: 1.5 m x 1.7 m (width x height) Opening factor: O m 1/2 Natural fire tests

89 Testing programme Fire test BE bb g BE bb o I BE bb o II Safety concept technical (sprinkler) technical (sprinkler) technical (sprinkler) Fire type Modules Window opening pre-flashover fire pre-flashover fire pre-flashover fire BÜ nbb structural post-flashover fire BÜ bb structural post-flashover fire BÜ nbb demo structural post-flashover fire Room linings H1 closed combustible H1 opened combustible H1 opened combustible lower: G1 upper: H2 lower: H1 upper: H2 lower: G2 upper: H2 opened closed opened closed opened closed non combustible combustible combustible combustible non combustible combustible Natural fire tests

90 Testing programme Pre-flashover fire tests (Series BE) Post-flashover fire tests (Series BÜ) Opened window Closed window Natural fire tests

91 Sprinkler systems All modules equipped with two sprinkler systems on the ceiling on a wall Activating temperature ceiling sprinkler: 57 C (RTI: 35 ms 0.5 ) or 68 C (RTI: 50 ms 0.5 ) wall sprinkler: 68 C (RTI: 50 ms 0.5 ) ceiling sprinkler wall sprinkler Natural fire tests

92 Fire ignition and fire load Movable fire load mattress made of foam material 11 wooden pallets Fire ignition 4 dl n-heptane below mattress Fire load density BÜ nbb BÜ bb BÜ nbb demo Movable fire load density 234 MJ/m MJ/m MJ/m 2 Additional fire load density 129 MJ/m MJ/m MJ/m 2 Total fire load density 363 MJ/m MJ/m MJ/m 2 Natural fire tests

93 Results of pre-flashover fire tests (Series BE) Fire test Time of mattress ignition [min] Sprinkler on the ceiling a [ C] a t a [min] b Sprinkler on the wall a [ C] a t a [min] b Fire detection systems (FDS) Measured detecting time [min] FDS 1 FDS 2 FDS 3 FDS 4 BE bb g ca C C (air) BE bb o I ca C C (air) BE bb o II ca C (air) C Activating time of sprinkler systems: 2-3 minutes after fire ignition No significant differences between ceiling and wall sprinkler system No influence of ventilation conditions (window opened or closed) FDS discovered fire within two minutes Natural fire tests

94 Room temperatures on the ceiling (BE bb g) Natural fire tests

95 Efficiency of automatic extinguishing systems: sprinkler Natural fire tests

96 Results of post-flashover fire tests (Series BÜ) Fire test BÜnbb BÜbb BÜdemo Modules lower: G1 upper: H2 lower: H1 upper: H2 lower: G2 upper: H2 Window opened closed opened closed opened closed Ignition time of mattress Flashover Failure time of exterior window glass Failure time of interior window glass Sprinkler on the ceiling (air) Sprinkler on the wall (air) End of fire test (intervention of fire brigade) n.u n.u n.u n.u n.u n.u (air) (air) (air) C (air) h (air) 68 C (air) Natural fire tests

97 Influence of combustible surfaces in room hotel Fire after 7 minutes after fire ignition Combustible Non combustible Natural fire tests

98 Influence of combustible surfaces in room hotel Combustible room linings Non combustible room linings Natural fire tests

99 Room temperatures on the ceiling (BÜ nbb and BÜ bb) Temperature in the rear of the module lower than in the front No significant differences in the temperature curves for BÜ nbb and BÜ Natural fire tests

100 A total burn-out without loss of structural stability and the main compartmentation was guaranteed by the structure Natural fire tests

101 Tall building project Example Dock Tower Tall timber building of 120 m Primary fire compartment central core and four external staircases projecting concrete slabs after every three storeys Secondary fire compartment Residential apartments designed according to the requirement of burn-out Example Dock Tower

102 Tall building project Staircases Five staircases Four staircases designed as escape routes Two staircases are pressurized to avoid smoke to enter All rooms are equipped with a water mist system and fire alarm system Fire safety level higher than that in tall buildings designed based on the standard measures Example Dock Tower

103 Signal Timber Building Mandat International Tall timber building design study Example Innovative Green Building of Mandat International

104 Green Building Vision Some Facts Building responsible for 40-50% of energy consumption Green Buildings have important impact on environment and climate change Zero or + energy buildings are feasible (LEED, Green Star, Green Globes, DGNB, Minergie...) Example Innovative Green Building of Mandat International

105 Green Building Vision Geneva Innovative Green Building of Mandat International to become a signal building and potential showcase worldwide Dissemination of knowledge in energy and environmental design through international delegates Innovative Green Building concept must not increase construction and maintenance cost Example Innovative Green Building of Mandat International

106 Geneva Green Building Vision - Conditions Fire safety objectives for people and goods must be guarantied and fulfil highest standards (fire laws) Performance of building must be checkable (Minergie P Eco envisaged) The Green Building must offer high standard living and working space to the international delegates Example Innovative Green Building of Mandat International

107 Geneva Green Building Vision - Implementation Use of performance based design methods and check with computer simulations Mixed wood-concrete structure using renewable wood and C0 2 reduced green cement Certified to Minergie P Eco Standard Fire Safety fulfilling all safety objectives and Geneva fire laws Example Innovative Green Building of Mandat International

108 Signal Timber Buildings Mandat International Tall timber building - Design study Timber structure Concrete core with CO 2 reduced cement Innovative building technology Green Signal Building Example Innovative Green Building of Mandat International

109 Signal Timber Building Mandat International Tall timber building (12 storeys, 38m) design study Concrete slab 36m 38m Example Innovative Green Building of Mandat International

110 Signal Timber Building Mandat International Tall timber building (12 storeys, 38m) design study Concrete slab Example Innovative Green Building of Mandat International

111 Signal Timber Building Mandat International A Green Building for Mandat International in Geneva using wood is feasible and will become a signal building and important showcase worldwide It will support the dissemination of knowledge in energy and environmental design through the international delegates The innovative green Building will offer the international delegates high comfort with-out compromising on sustainability and it will strengthen their desire to fight against climate change Example Innovative Green Building of Mandat International

112 Conclusions The use of combustible materials in tall buildings is restricted in most fire regulations People in tall buildings can often not be evacuated by the fire brigade using external equipment A total burn-out without loss of structural stability and some main compartmentation must be guaranteed by the building structure For the use of timber this often leads to the protection of the timber by non-combustible material (encapsulation) or to mixed construction Mixed timber-concrete tall buildings in combination with technical and organizational measures can be built to be as safe as typical traditional non-combustible tall buildings

113 Behavior of CLT in fire Andrea Frangi ETH Zurich Institute of Structural Engineering NEWBuildS Research Exchange, Hybrid Building Systems Ottawa, June 13, 2011 Datum

114 Cross-Laminated Timber Panels = Solid Timber? Full-scale natural fire test Tsukuba (Japan), March 6, 2007, 3-storey timber building made of cross-laminated solid timber panels

115 Cross-Laminated Timber Panels (CLT) CLT are produced from industrially dried spruce boards which are stacked crosswise and glued together over their entire surface CLT with 3, 5, 7 or more board layers Width of single boards between 80 and 240mm Thickness of single boards between 10 and 35mm Differences from solid timber Layered cross-section Joints Introduction

116 Advantages - Stiffness - Robustness Disadvantages - Increased fire load in the room

117 Fire behaviour of timber Pyrolysis: thermal degradation of wood producing combustible gases and accompanied by a loss in mass (starting from about 250 C) Charring rate : Ratio between charring depth d char and fire time t (in mm/min) Fire time t = 63min Residual cross-section d char t d char 50mm 0. 8mm t 63min min Char layer Introduction

118 Charring rate according to EN Material 0 [mm/min] n [mm/min] Softwood Glued laminated timber with a characteristic density 290 kg/m Solid timber with a characteristic density 290 kg/m Panels Wood panelling Plywood Wood-based panels other than plywood Charring rate of Cross-Laminated Timber Panels? 0.65 mm/min mm/min Introduction

119 Fire behaviour of protected timber surfaces Charring depth [mm] Unprotected timber surfaces Charring rate not constant Increased charring rate after failure of cladding Timber element 10 Cladding Time [min] Protected timber surfaces Introduction

120 Charring model for protected timber surfaces according to EN Charring depth d char,0 or d char,n [mm] b 2c 25 mm Charring rate: ( phase 2b ) k with k ( phase 2c ) 3 0 t ch = t f Time t t a With t ch = time of start of charring; t f = failure time of cladding (fall off) For wood-based panels and gypsum plasterboards type A or H: t ch = t f Introduction

121 Fall off of charred layer 3-layered timber panel OSB Influence of fall off of charred layers Timber slab after 17 minutes ISO-fire exposure

122 FE-thermal analysis ANSYS res = 0.8 c = 25W/m 2 K Density, specific heat and thermal conductivity of wood and charcoal according to EN Temperature [ C] ISO-fire curve Fire tests [10] FE-Results 6mm 18mm 30mm 42mm Time [min] FE- thermal analysis

123 FE-thermal analysis Extensive parametric study on charring of CLT panels: thickness of single boards as main parameter Timber elements exposed to ISO-fire on one side Charring depth calculated as the position of the 300 C isotherm For CLT it was assumed that the charcoal falls off after the layer is completely charred, i.e. when the temperature at the interface between the layers reaches 300 C Example 1 Example x x28 FE- thermal analysis

124 FE-thermal analysis = 1.3 mm/min = 1.0 mm/min 85 Charring depth [mm] Example 1 84 Charring depth [mm] Example Solid timber CLT CLSTP Time [min] Solid timber CLSTP CLT Time [min] FE- thermal analysis

125 FE-thermal analysis Conclusions Charring rate of CLT is not constant as the fire progresses Increased charring rate is observed after the protective charcoal of a layer has fallen off The later the charcoal falls off, the more the charring rate increases! Large influence of the thickness of the single layers CLT consisting of 3 layers with 28 mm thickness better than CLT consisting of 5 layers with 17 mm thickness FE- thermal analysis

126 Fire tests Cross-laminated timber panels after 55 minutes ISO-fire exposure

127 Small-scale fire tests on CLT panels Fire test Number of layers Thickness layers [mm] Total thickness [mm] Adhesive Layers orientation V1 5 10/10/10/10/20 60 MUF crosswise V2 5 10/10/10/10/20 60 PU 1 crosswise V3 5 10/10/10/10/20 60 PU 1 parallel V4 2 30/30 60 PU 1 crosswise V5 2 30/30 60 MUF crosswise V6 5 10/10/10/10/20 60 PU 2 crosswise V7 5 10/10/10/10/20 60 PU 3 crosswise V8 3 20/20/20 60 PU 3 crosswise V9 5 10/10/10/10/20 60 PU 4 crosswise V /20/20 60 PU 4 crosswise V /20/20 60 PU 5 crosswise Fire tests

128 Small-scale fire tests on CLT panels T25 T24 T23 T22 T21 T15 T14 T13 T12 T11 T5 T4 T3 T2 T1 furnace burners x10 T25 T21 T15 T11 T5 T1 timber panel cross-laminated timber panel Fire tests

129

130

131 Small-scale fire test results on CLT panels Fire Test V Temperature [ C] T1/11/21 T2/12/22 T3/13/23 T4/14/24 T5/15/25 Furnace ISO-fire Time [min] Fire tests

132 Small-scale fire test results on CLT panels 60 Charring depth [mm] V1 V2 V3 V6 V7 V9 0.65mm/min Time [min] Fire tests

133 Small-scale fire test results on CLT panels 60 Charring depth [mm] MUF (V1) PU1 (V2) PU2 (V6) PU3 (V7) PU4 (V9) Time [min] Fire tests

134 Small-scale fire test results on CLT panels 60 Charring depth [mm] crosswise (V2) parallel (V3) Time [min] Fire tests

135 Comparison to EN Charring depth [mm] EN V2 V3 V6 V7 V Time [min] Fire tests

136 Small-scale fire tests on timber panels Conclusions Fire behaviour of CLT panels depends on the behaviour of the adhesive used for bonding Fall off of the charred layers was observed for PU bonded CLT panels An increased charring rate was observed after the charred layers have fallen off The simplified bilinear model adopted by EN for initially protected surfaces can be used for the calculation of charring of CLT panels in the case that the charred layers fall off. Fire tests

137 Is the effect of falling off significant? d char Fire time: 60 min; Charring rate: 0.65mm/min t 1 = 34/0.65 = 52min Falling off: No falling off: d char = 34 + (60-52)*2*0.65 = 44mm d char = 34 + (60-52)*0.65 = 39mm Fire tests

138 Is the effect of falling off significant? Taking into account that the second layer on the fire exposed side is usually statically ineffective, for common CLT panels with the thickness of the single boards in the range of 20 to 35mm the effect of falling off of charred layers on the load-carrying capacity in fire is therefore relative small. Fire tests

139 XLam Timber building Timber building

140 Timber building

141 XLam Timber building (1) Plaster 10 mm Outside Wall 3 (2) Wood Fibre 120 mm (3) XLam Panel 85 mm (4) Mineral wool 27 mm (5) Standard gypsum wallboard 12 mm (6) Fire proof gypsum wallboard 12 mm Inside (1) (2) Fire proof gypsum wallboard 12 mm Standard gypsum wallboard 12 mm Fire Room Wall 4 (3) Mineral wool 27 mm (4) XLam Panel 85 mm (5) Mineral wool 27 mm (6) (7) Standard gypsum wallboard 12 mm Fire proof gypsum wallboard 12 mm Room B Timber building

142 XLam Timber building (1) Standard gypsum wallboard 12 mm (2) Mineral wool 27 mm Fire Room Wall 5 (3) XLam Panel 142 mm (4) Mineral wool 27 mm (5) Standard gypsum wallboard 12 mm Room A (1) Wood flooring 20 mm (2) Concrete topping 50 mm (3) Polyethylene sheet Floor and ceiling (4) Sand 60 mm (5) XLam Panel 142 mm (6) Mineral wool 27 mm (7) Fireproof gypsum wallboard 12 mm Timber building

143 Test measurements Timber building

144 Fire load and fire ignition For example: EN (Table E.4) gives for rooms of residential buildings an average fire load density of 780 MJ/m 2 Brandlast = 790 MJ/m 2 Fire load and fire ignition

145 Fire load Fire load density = 790 MJ/m 2 Fire load and fire ignition

146 Fire test Fire test

147 Fire test After about 32 minutes after fire ignition After about 40 minutes after fire ignition Fire test

148 Room temperatures 2.85m 2.22m 1.48m 0.74m Fire room 0.1m Flashover after failure of both window glasses after about 36 minutes Fire test

149 Temperatures on South wall Fall off of gypsum boards Fire test

150 Fire room damages Fire test

151 Fire room damages Charring depth measured on the East side wall after the fire test Fire test

152 Full-scale natural fire test Conclusions With pure structural measures it was possible to limit the fire to the fire room; no fire spread to adjacent rooms In the room above the fire compartment no elevated temperatures were measured and no smoke was observed By protecting the timber structure with gypsum plasterboards the damage of the Xlam solid timber panels was relative small