Quantification of Green Building Features on Firefighter Safety

Transcription

1 2017 NFPA Conference & Expo Quantification of Green Building Features on Firefighter Safety Handout Material Selected Presentation Slides Presented by: Praveen Kamath, WPI Brian Meacham, WPI Michael Gollner, UMD Brief overview of project and Year 1 and 2 research and outcomes Overview of Year 3 (and 4) research and outcomes Natural ventilation Structural performance of domestic systems Comparative risk assessment tool Potential implications / considerations for the fire service Future research needs WPI and UMD (2017) 1

2 The goal of this effort is to reduce firefighter injuries and deaths associated with unknown or unanticipated fire environments and structural responses associated with green building elements. Our objectives are to understand, quantify and address fire performance challenges of green building elements as they might impact firefighter safety during fire ground operations. The push to green buildings is growing. This can include reducing building materials, adding insulation, and installing alternative energy sources. However, the extent to which such green building elements and features may increase fire risks or hazards, or decrease building safety performance, has not been systematically studied. WPI and UMD (2017) 2

3 22 Fire Risk / Hazard Attributes Presents a potential hazard E.g., ignition, electrical shock, explosion, toxicity Hazard attributes E.g., readily ignitable, burns readily once ignited, contributes more fuel / increased HRR, etc. Failure potential E.g., shorter time to failure, failure affects burning characteristics or smoke spread or May impact building FP system or feature E.g., smoke/heat venting, suppression effectiveness, apparatus access, firefighter access & operations Research Scope Understand green building hazards Develop risk/hazard screening tool Structural Testing Test residential scale compartments and structures post flashover fire to focus on structural failure Ventilation Testing Identified Firefighter Injuries or Fatalities in the Green Elements from FIDO Database ( ) Commercial Occupancy 11% Salt water modeling Residential Occupancy 89% WPI and UMD (2017) 3

4 Team Worcester Polytechnic Institute (WPI) Brian Meacham, Nicholas Dembsey, Praveen Kamath, Honggang Wang, Qiang Kan, Matt Yin, Drew Martin, Young-Geun You, Michael Figueroa University of Maryland (UMD) Michael Gollner, Andre Marshall, Pietro Maisto, Jens Triller, Jan Zimlich, Wuquan Cui Fire Protection Research Foundation (FPRF) Casey Grant, Amanda Kimball / Project Technical Panel National Fire Protection Association (NFPA) Rita Fahy, Marty Ahrens, and John Hall Massachusetts Department of Fire Services (DFS) Paul Vigneau Domestic Structural Systems WPI and UMD (2017) 4

5 9 NFPA Annual Conference, June 2015 SIPs are composite structural panels with an insulating core of rigid foam and structural facings. Used for wall, floors and roofs. WPI and UMD (2017) 5

6 2 Semi-Permanent Walls Steel construction, single vent opening, 8 gas burners Dimensions Length 16 ft. (4.88 m) Width 14 ft. (4.27 m) Height 16 ft. (4.88 m) Designed to test 1-level, 1.5- level, and 1-level with roof Designed for loaded structure WPI and UMD (2017) 6

7 Ignition of Propane Burners WPI and UMD (2017) 7

8 Temperature ( C) Temperature ( C) 800 North East Corner TC Tree 700 Series1 600 Series2 Series3 500 Series4 400 Series Time (m) Series1 Series2 Series3 Series4 Series6 Series7 Stud Cavity: North Wall Time (m) WPI and UMD (2017) 8

9 Full-Depth Charring of Ceiling Joists at Mid-Span Full-Depth Charring of Ceiling Joists at Supports Burning Wall Studs (Flame leak through cracked gypsum drywall) Burning Wall Studs (Flame leak through wall-roof connection) WPI and UMD (2017) 9

10 Stay tuned - to be presented! Stay tuned - to be presented! WPI and UMD (2017) 10

11 Stay tuned - to be presented! Natural Ventilation WPI and UMD (2017) 11

12 Natural ventilation is more sensitive to external conditions and changes than forced ventilation Opening or closing windows/doors Boundaries are being pushed removing compartmentalization No guidelines on how to respond Open Windows/Doors or allow automatic function How long is necessary for evacuation? When will buildings fail? Potential for unexpected consequences Forced convection through a compartment Highly dependent on external conditions Some designs have sensitive control algorithms WPI and UMD (2017) 12

13 Driven by density difference between interior/exterior due to temperature differences The Gherkin in London. Windows open on the outer skin to allow air to enter the cavity between the inner and outer skin. WPI and UMD (2017) 13

14 Add stack or air barrier to encourage heating/ cooling Potentially lose separation Operable windows Potential Fire movement in Façade Simon Lay, Presentation to NFPA Green Building Symposium, Chicago, Il, The Gherkin in London. Windows open on the outer skin to allow air to enter the cavity between the inner and outer skin. Natural Ventilation Indoor Comfort Heating or Cooling Stratified or Mixed Smoke Control Vent in case of fire Time for proper evacuation Must remain stratified Warm Air Cooling Configuration (stratified) Smoke WPI and UMD (2017) 14

15 Model smoke movement in naturally-ventilated enclosures including (1) Resolution study in large enclosures (2) Large atria openings (3) Double-skinned facades (4) Inclined ceilings Develop simple engineering models to Anticipate external effects on smoke movement Highlight dangerous scenarios/configurations Translate this into better firefighting practices and code recommendations Combine CFD with Saltwater Modeling Validate smoke movement without large scale Saltwater Modeling Nd-Yag Laser PIV (velocities) PLIF (densities/temp) WPI and UMD (2017) 15

16 Unit Approach Interchangeable acrylic models to Scale test models ventilation proposed configurations to test smoke filling dynamics of green building features including (a) a sloped roof atria configuration with a fire source in the lower right hand corner and (b) a combined solar chimney, two room, atria and slatted doubleskinned façade configuration. Smoke layer height vs. dimensionless time, m*= 3.9e-6, measured at x 1 H = 0.5 WPI and UMD (2017) 16

17 Stay tuned - to be presented! To provide realistic test results that can be completely transferable to real life the model dimensions are based on the 30 St Mary Axe (widely known informally as The Gherkin) A representative room of the 22 nd floor was chosen as a basis of the dimensions for building the enclosure. The scales of the several chosen dimensions will be the following: Room height: 0.180m 3.9m = Room length: 0.280m 6m = Double Skin façade length: 0.06m 1.3m = WPI and UMD (2017) 17

18 The model was built out of acrylic that makes it possible to run experiments with salt water modeling It dissembles two floors with a double skin façade and louvers, which are a common element used for sun protection and natural ventilation Model has two basic features: Exchangeable windows (1) Adjustable angle of louvers (2) Closed Louvers at Enclosure 90 Position Louvers at Enclosure The model gives the opportunity to run salt water modeling experiences with various louver positions. That makes it possible to compare the different results and so helps to understand how the louver angle effects the smoke behavior 90 Position Louvers Double Skin façade Closed Louvers Double Skin façade WPI and UMD (2017) 18

19 Three different louver positions were tested: a) 90 b) 45 Meacham, c) 2017 Closed Stay tuned - to be presented! WPI and UMD (2017) 19

20 Stay tuned - to be presented! WPI and UMD (2017) 20

21 Hazard / Risk Tool Material Fire Performance Short time to failure Structural Fire Performance Potential to Collapse Firefighter Operations Defensive Attack Keep Searching Trapped Consequences Fire Growth Injuries or Fatalities Injuries or Fatalities Risk of Lightweight Construction Failure on Fire Service WPI and UMD (2017) 21

22 Several risk assessment approaches available Target was quantitative, but need data 43Meacham, NFPA Annual 2017 Conference, June 2015 Ramachandran, G., and David A. Charters. Quantitative Risk Assessment in Fire Safety. London: Spon, Print. Exterior Materials and Systems - Structural integrated panel (SIP) - Exterior insulation & finish (EFIS) - Rigid foam insulation - Spray-applied foam insulation - Foil insulation systems - High-performance glazing - Low-emissivity & reflective coating - Double-skin façade / cavity wall - Bamboo, other cellulosic - Bio-polymers, FRPs - Vegetative roof systems - Insulating material - Thickness - Type of vegetation - PVC rainwater catchment - Exterior cable / cable trays - Extended solar roof panels - Exterior solar shades / awning - Exterior vegatative covering Façade Attributes - Area of glazing - Area of combustible material Risk Ranking Key Low or N/A Moderate High Poses potential ignition hazard Poses potential shock hazard Potential explosion hazard Poses potential toxicity hazard Readily ignitable 44Meacham, NFPA Annual 2017 Conference, June 2015 Contributes more fuel / increased HRR Burns readily once ignited Material affects burning characteristics Fast(er) fire growth rate Significant smoke production/hazard Failure presents stability concern Potential for shorter time to failure Failure presents smoke spread concern Failure affects burning characteristics Material presents flame spread concern May impact smoke/heat venting Failure presents flame spread concern May impact occupant evacuation May impact fire apparatus access May impact FF water availability Presents a low risk when unmitigated or is not applicable to the listed attributes Presents a moderate risk when unmitigated. Presents a high risk when unmitigated. May impact FF access and operations May impact suppression effectiveness May impact containment of runoff Relative risk level WPI and UMD (2017) 22

23 Selected comparative risk approach Insufficient statistical (historical) fire loss data, and insufficient fire test / experimental performance data on materials and systems for absolute risk approach Comparative approach allows establishment of a benchmark, for which sufficient data are available, and look at relative increase or decrease in risk Benchmark is traditional 2 x4 stick construction WPI and UMD (2017) 23

24 How to fix weighting factors? Time How does a green building feature affect the fire growth or structural stability? WPI and UMD (2017) 24

25 How does a green building feature finally affect the occupants safety or Fire fighters safety? WPI and UMD (2017) 25

26 Stay tuned - to be presented! Outcomes, Conclusions, Future WPI and UMD (2017) 26

27 Stay tuned - to be presented! Stay tuned - to be presented! WPI and UMD (2017) 27

28 Stay tuned - to be presented! Thank you for your attention! Questions? WPI and UMD (2017) 28

29 2017 NFPA Conference & Expo CEUs: To receive CEUs for this session, scan your badge at the back of the room before leaving Evaluation: Complete a session evaluation on the mobile app. (Search app store for NFPA 2017 C&E. ) Handouts: Handouts will be available via the mobile app and at nfpa.org/conference Recordings: Audio recordings of all sessions will be available free of charge via NFPA Xchange. WPI and UMD (2017) 29