Natural Ventilation A Green Smoke Control Approach

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2 Natural Ventilation A Green Smoke Control Approach Presented By: William Koffel, P.E., FSFPE Adam Graybeal, P.E. Authored by: Erik Anderson, P.E Koffel Associates

3 Background New Engineering, Aviation, Computer & Mathematical Sciences Building (EACMS), University of Maryland Eastern Shore in Princess Anne, Maryland Construction completed early 2016

4 Design Intent Designed per: 2012 International Building Code (IBC) 2012 Life Safety Code (LSC) Amendments per State of Maryland and UM

5 Building Information Building Structure: Three (3) stories each approximately 15 ft (4.6m) 3-story atrium extends from the Ground Level up to a clearstory above the 3rd floor for an approximate height of 55 ft (16.8m).

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7 EACMS Third Floor Plan

8 EACMS Fire Model Geometry

9 Design Approach Natural Smoke Exhaust System in Lieu of Mechanical Smoke Control System Used algebraic equations first (NFPA 92 and 204) Fire Dynamics Simulator (FDS) used to further evaluate anticipated conditions within atrium.

10 Design Approach Smoke exhausted from top of Atrium Tenable conditions maintained from the bottom of the atrium to 6 ft (1.8m) above the highest walking surface. Four (4) Design Fire Scenarios Axisymmetric and Spill Plume

11 Ground Level Center Fire Location

12 Ground Level - Underneath Stairs

13 Ground Level Axisymmetric Plume

14 Second Floor Opening in South Hallway

15 Design Fire Scenarios Constant 5 Megawatt (MW) for each fire Each fire scenario was modeled with: No wind, 30 mph (48 kmph) wind, 60 mph (96 kmph) wind. Directional wind Sensitivity analysis

16 Tenability Criteria Visibility was evaluated to be maintained for a period of at least 20 minutes. Minimum visibility distance of 30 ft (9.1 m)was cited as the threshold above which egress is impeded through the smoke layer.

17 Tenability Criteria Maximum temperature criteria: Maximum temperatures of 169 F (76 C) during egress Maximum temperature of 392 F (200 C)

18 Unique Design Considerations Awning Type Smoke Exhaust Windows Venting Locations and Size based on calculations methods from NFPA 204, Smoke and Heat Venting, 2012 Edition.

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20 EACMS Fire Model Geometry

21 Unique Design Considerations Make-up air is provided by two sets of 6 ft x 8 ft (1.8 m x 2.4 m) double doors at each of the four entrances. Additional air from two extra vents by both of the East and West entrances.

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23 Unique Design Considerations Actual venting area: 48 windows along the clearstory Each vent is 4.5 ft x 4.5 ft (1.4 m x 1.4 m) Total of 972 square feet (90 sq m) of actual venting Effective venting area = 340 sq ft (31.5 sq m)

24 Exhaust Activation Method Beam detection along the roof Sprinkler activation Manual means

25 Modeling Results No Wind *Activation time may be due to placement of sprinkler in relation to fire. **In the same model, another sprinkler activated after 89 seconds ***Sprinklers located on the 3 rd Floor in the South Hall

26 Normal Stack Effect Results *Sprinklers located on the 3 rd Floor in the South Hall

27 Reverse Stack Effect Results *Sprinklers located on the 3 rd Floor in the South Hall

28 Lessons Learned Natural ventilation can be used in lieu of mechanical smoke control for some building configurations. Decision to use natural ventilation must be done early in the design process. Design team buy-in. Allow time to coordinate system requirements with AHJ and make the appropriate architectural changes needed. Effect on building design and layout.

29 Lessons Learned NFPA 92 and 204 calcs provide a good estimate. Wind and stack effect significantly impact venting capability. LARGE vent openings are required. Remember the details: Window actuators (how far open?) Venting coefficient Automatic make-up air approach Listed smoke control panel/controls

30 Lessons Learned Sensitivity analysis required for model input variables such as vent arrangement, grid size, beam detection locations, and sprinkler activation temperature alter results. AHJ must ensure variables used are clearly indicated in any submitted fire modeling report.

31 Natural Ventilation A Green Smoke Control Approach Presented By: William Koffel, P.E., FSFPE Adam Graybeal, P.E. Authored by: Erik Anderson, P.E. Koffel Associates