Fire Hazard Analysis of Technical Area 53 Building 1

Transcription

1 Fire Hazard Analysis of Technical Area 53 Building 1 June 11, 2015 LA-UR Slide 1

2 Introduction Brett Noakes Los Alamos National Laboratory Los Alamos, New Mexico Slide 2

3 Outline Background of the building Prescriptive Analysis Egress Evaluation Fire Protection Alarm System Evaluation Fire Protection System Evaluation Fire Protection Structural Evaluation Fire Safety Plan Overview Slide 3

4 Outline Performance Based Analysis Scope Goals Stakeholder Objectives Performance Criteria Design Fire Scenarios Analysis Slide 4

5 References 1. National Fire Protection Association. NFPA 101 Life Safety Code. Quincy, Massachusetts : National Fire Protection Association, Fire Protection Handbook 20th Edition. Quincy, Massachusetts : National Fire Protection Association, National Fire Alarm and Signaling Code. Quincy, Massachusetts : National Fire Protection Association, NFPA NFPA 13 Standard for the Installation of Sprinkler Systems. Quincy, Massachusetts : National Fire Protection Association, NFPA NFPA 25 Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems. Quincy, Massachusetts : National Fire Protection Association, NFPA International Code Council. International Building Code. Country Club Hills, IL : International Code Council, Los Alamos National Laboratory. LANL Emergency Procedures and Protective Actions. Los Alamos : LANL, No: P R2. 8. Society of Fire Protection Engineers. SFPE Engineering Guide to Performance-Based Fire Protection Analysis and Design of Buildings. Quincy, Massachusetts : National Fire Protection Association, Society of Fire Protection Engineers. THE SFPE Handbook of Fire Protection Engineering Fourth Edition. Quincy, Massachusetts : National Fire Protection Association, Thunderhead Engineering. PyroSim 2015 Manual. PyroSim. [Online] Thunder head Engineering, [Cited: May 5, 2015.] Thunderhead Engineering. Pathfinder User Manual. Pathfinder Resources. [Online] Thunderhead Engineering, [Cited: May 5, 2015.] Ni, W.K. Chow and Xiaomin. Experimental Evaluation on Performance of Open Kitchen Fire Suppression Systems. Hong Kong, China : Fire Safety Science-Draft Proceedings of the Eleventh International Symposium, Slide 5

6 Building Background Built in 1971 Approximately 81,000 square feet Partial basement under Wings C and D Wing A is two story Wing B houses an auditorium and small cafeteria D C B A Aerial View of Building 1 Slide 6

7 Prescriptive Analysis Building 1 was evaluated against current codes to see how this 1971 construction would compare. Slide 7

8 Egress Evaluation NFPA 101 Life Safety Code 2012 Edition Building 1 is a mixed occupancy with both Business and Assembly Assembly occupancy is limited to the lecture hall and the cafeteria Building was split in the 4 fire areas to easier segregate the analysis Area 1 consists of A wing Offices Area 2 consists of B wing Assembly (Auditorium), lounge, café, offices Area 3 consists of Wing C Offices, basement area, additional work spaces, and mechanical space(s) Area 4 consists of Wing D Offices, basement area with additional work space, and mechanical space(s) Slide 8

9 Occupancy Identifications D Wing First Floor Plan Slide 9

10 Occupancy Identifications Wing C, B and A First Floor Plan Slide 10

11 Occupancy Identifications Wing B and A Second Floor Plan Slide 11

12 Occupancy Identifications Basement Floor Plan Slide 12

13 Egress Evaluation Basement Egress Components Three internal stairs Two external egress doors (36 and 72 ) Wing D Egress Components Four 72 doors and one 36 door Wing C Egress Components Three 72 doors Wing B Egress Components Two 72 doors and one 36 door Auditorium has two 36 doors that egress direct to the exterior The cafeteria has a 72 door that egresses to the exterior Wing A Egress Components 1 St floor Two 72 doors and one 40 door 2 nd floor One 48 stair and one 44 stair; both are restricted by 36 doors Slide 13

14 Egress Evaluation Area Capacity of Egress Components Basement Note: Capacity (NFPA 101 Table ) Stairs Capacity Factor.3, Door Capacity Factor.2 Required Egress Capacity Slide 14

15 Means of Egress Features Area NFPA 101 Requiremen t Exit Stairs Enclosed 1. (2) Stairs (total) (1) Enclosed Travel Distance 300 ft. Sprinkler Protected Building Common Path of Travel Dead End Corridor Length 100 ft. 50 ft. Exit Signs Emergency Lighting <100 ft. <20 ft. None Tritium Yes 2. None <100 ft. <20 ft. None Tritium Yes 3. (3) Stairs (total) (2) Enclosed 4. (1) Enclosed Stair <150 ft. 75 ft. 36 ft. Tritium Yes <150 ft. 70 ft. 36 ft. Tritium Yes Slide 15

16 Evacuation Time Estimated pre-movement delay is 2 to 3 minutes Complacency with regards to notification appliances Securing sensitive material Gathering belongings before leaving Calculated Evacuation Time = 2.5 minutes Total occupant load of 1703 people 14 exits which allows 122 people per exit 36 with 6 boundary layer on both sides 24 people per minute per foot of effective width 48 people per minute through the door 122/48= 2.5 minutes egress time plus the 3 minute premovement time = 5.5 minutes to egress (exaggerated) Slide 16

17 Fire Protection Alarm System Evaluation The alarm system was updated in 2004/2005 time frame Addressable system 2 NAC circuits Signals are transmitted through a DACT off site to a central station to be dispatched accordingly Building 1 has a fully compliant NFPA 72 system Building 1 has some strategically placed smoke detection for early warning capability Telecommunications room Computer room Required above the FACP Slide 17

18 Fire Protection Alarm System Evaluation DETACT Model Fire in computer room Activation based on a temperature rise of 7.2 C (PVC from NFPA 72) Fast growth rate (PE from NFPA 72) DETACT model showed an activation time of 41 seconds at the HRR of 79kw Calculation Results from DETACT Model Slide 18

19 Fire Protection Alarm System Evaluation Notification Appliances Located in all corridors Lobbies, restrooms, and conference rooms Devices that are the most demanding were found in mechanical rooms Evaluated using the 6dBA rule of thumb Devices are set at 110dB which is their max (acceptable) Strobe coverage (acceptable) Battery Calculations Standby power.25 amps X 24 hours = 6 AH required Alarm power 2.46 amps X 10 minutes (laboratory required) = 10/60 = 1.67 X 2.46 =.41 AH required Total with 20% safety factor = 7.69 amp hours required The system is supplied by two 12AH batteries Slide 19

20 Fire Protection System Evaluation Building 1 is protected by two suppression systems SPW-001 protects Wings A, B, and C (hydraulically designed) SPW-002 protects Wing D (believed to be pipe scheduled) Both believed to be 1981 vintage The SPW-001 system is thought to be designed to.19 gpm/ft 2 over 1500 ft 2 (1980 NFPA 13 COR) system was calculated using.2 gpm/ft 2 over 1500 ft 2 The hand calculations show a system demand of gpm at psi I did not have good drawings and was not able to field verify There are a lot of guesses in the calculation with regards to fittings, elevation changes, and pipe lengths The system needs to be field verified and recalculated using computer hydraulic calculation software After a quick reevaluation of the hand calculation, over-estimations were made and the demand was verified down to gpm at 78.9 psi Slide 20

21 Fire Protection System Evaluation The hydraulic design data that is available indicates BoR requirement of 663gpm at 65 psi Heads are standard spray sprinklers with 212 F elements (both systems) Both systems have pressure switches with retard chambers with redundant sets of paddle type flow switches that divide the systems into zones (wing and floor) Slide 21

22 Fire Protection System Evaluation Hydraulic Graph Combined Curve With 500 gpm hose System Demand psi 140% X70 psi 75 psi Residual Reexamined system demand psi 70 65% X70 X1250 gpm 63 gpm Slide 22

23 Fire Protection Structural Evaluation 81,000 square foot building Fully compliant NFPA 13 suppression system Cast-in place concrete, concrete tee, concrete block and steel joist Exterior walls are concrete block with 30 to 40% insulated spandrel glass openings Foundation walls, tunnels, and footers are cast-in place concrete Slide 23

24 Fire Protection Structural Evaluation Floor/ceiling assemblies between floors are concrete tee construction The roof/ceiling assemblies are steel joists covered with (4 inches) lightweight concrete If not for the unprotected steel joists, the facility would be entirely fire resistive construction (Type I) As built it is Type II B construction Slide 24

25 Fire Protection Structural Evaluation Occupancy Classification Majority Group B with 2 assembly areas A-3 lecture hall A-2 cafeteria IBC 2012 indicates a separation from Group A and B occupancies to be 1 hour (with suppression), which we have with cement block walls and rated doors Slide 25

26 Fire Protection Structural Evaluation Construction Requirements Building 1 is 22 above grade with one level 14 below grade and does not qualify for a high-rise building Height and Area 81,000 square feet with two stories above grade First floor is 47,680 square feet, second floor is 10,345 square feet, and a basement square footage of 23,221 The area of the first floor exceeds the allowable limits of all construction types except Type I 80,500 > 47,680 feet of the first floor All construction types could be used, but Type V B is eliminated based on allowable area. Slide 26

27 Fire Protection Structural Evaluation Type IIB has no fire resistance ratings that need to be achieved by the IBC With the lack of exposures to Building 1 there are no exterior wall fire resistance ratings that need to be applied Slide 27

28 Fire Safety Plan Overview Reporting Fires Building Evacuation Steps to evacuate Steps to help fellow coworkers with a special need Building Hazards Small quantities of flammable liquids Lasers Commercial kitchen Natural gas Electrical hazards Slide 28

29 Site Plan Slide 29

30 Performance Based Analysis Scope Goals Stakeholder Objectives Performance Criteria Design Fire Scenarios Analysis Slide 30

31 Performance Based Analysis (Scope) The scope of this project is to evaluate the tenability and structural response of Building 1 during likely fire scenarios. Two types of modeling software will be used for this analysis. The first model will analyze the egress system of Building 1 to help determine the available required safe egress time for Building 1, with the second model analyzing the effects of fire on Building 1 structural components and the egress system. Slide 31

32 Performance Based Analysis (Goals) Life Safety Tenability maintained for the entire RSET time for those not intimate with the fire Maintain Mission Operability No mission-critical operations in Building 1 Total loss fire not likely due to Building 1 s configuration Prevent structural damage during a fire event Slide 32

33 Performance Goals Limit temperatures to below 600 C to prevent structural damage Maintain visibility to at least 13 meters at height of 6 feet above the finished floor during the fire event for the RSET time Slide 33

34 Developing Design Fire Scenarios Cause Number of times found in search Open Flames 1 Electrical 5 Cooking 1 Spontaneous Ignition 1 Flammable and Combustible Materials 1 Human Error 3 Arson 5 Smoking 2 Hot Work 1 Slide 34

35 Developing Design Fire Scenarios References * _safety_in_the_workplace/2 Slide 35

36 Developing Design Fire Scenarios Assumptions One single fire will not affect Building 1 as a whole One fire can affect adjacent wings All fires happen when the building is occupied and in occupied areas (immediate notification) All doors of the room of origin and egress system will be open and stay open throughout the fire event Assumption is that all suppression is fully operational Fires will be placed in areas where they challenge Building 1 s egress system All models were run for 330 seconds the total RSET time Slide 36

37 Building Floor Plan Slide 37

38 Fire Scenarios Five fires were modeled for this building Trash fire at the junction of Wing A and Wing B A kitchen fire in Wing B A jacket fire in Wing C A basement fire in Wing C A flammable liquid fire in Wing D Slide 38

39 Basement Fire 3-foot-high stack of corrugated cardboard Slide 39

40 Basement Fire Peak HRR 617 kw A curve was found in the SFPE HB Figure for a similar material with a peak HRR of 2400 kw The curve had the peak at 600, seconds but was 0 kw at 500 seconds The fire was designed as a one-square-meter fuel package Slide 40

41 Basement Fire SCEA standard commodity- Swedish version of a pallet of corrugated cardboard boxes (12 boxes to a pallet), each box filled with polystyrene chips First sprinkler activation at 54 seconds (2) Slide 41

42 Basement Floor Plan Slide 42

43 Basement Fire Slide 43

44 Basement Fire Slide 44

45 Basement Fire Slide 45

46 Wing D Fire Flammable liquid spill (ethanol 1 liter) Estimate the size of the spill (1.4m 2 ) Estimate the maximum possible fire size (2.17m 2 ) Calculate the HRR of ethanol (1.27MW) = " *A* hc) Calculate the total burn time of the fire (17 seconds) t b = (V*ρ)/( " *A) Assume for flammable liquid fire that the peak HRR is reached immediately upon ignition and stays there for the duration of the burn time Fire was elevated 1 meter off the ground Flame height was calculated at 3 meters Slide 46

47 Wing D Fire Slide 47

48 Wing D Fire Sprinkler activation was in 2.5 seconds (4) Slide 48

49 Wing D Fire Slide 49

50 Wing D Fire Slide 50

51 Conclusion This analysis of Building 1 has shown that the 1971 vintage building does meet current building codes Building 1 s current configuration is acceptable on the basis of structural fire protection Smoke visibility levels could not be maintained to the more restrictive unfamiliar occupant distance of 13 meters during some of the design fires All models would have passed the less restrictive familiar occupant distance of 4 meters Slide 51