COSTCO, SAN FRANCISCO - Cal Poly

COSTCO, SAN FRANCISCOA PRESCRIPTIVE AND PERFORMANCE BASED ANALYSIS OF FIRE PROTECTION SYSTEMS AND DESIGN

Presented by Ian LevineJune, 2016

Photo courtesy of Google Maps

PRESENTATION OVERVIEW

BUILDING DESCRIPTION

STRUCTURAL DESIGN

ALARM AND DETECTION

EGRESS

SPRINKLER SYSTEM ANALYSIS

PERFORMANCE BASED ANALYSIS

Photo credit to FrenchiesGigiandLola via youtube


BUILDING OVERVIEW

TRUE NORTHPLAN NORTH

• Mixed OccupancyMercantileHigh Piled StorageRestaurantKitchen, BakeryOffice

• ConstructionConcrete slabExposed, noncombustible

• Area: 122,000 sq.ft.• Ceiling Height: 30 ft.• Open floor plan

Satellite Image courtesy of Google Maps

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Presented by Ian LevineWinter 2016


A LOOK INSIDE

Concrete floor

Rack storage

Wide aisles

Steel deck

Steel open web truss

Wide flange steel column

Details shown typical of all Costco stores

Steel wide flange beam

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Draft curtains

Ventilation

Presented by Ian LevineWinter 2016


STRUCTURAL DESIGN: What type of construction is allowed for this 122,000 sq.ft. structure?

Building Area: 122,000 sq.ft.Factor of increase based on frontage and automatic fire protection: 3.48

Maximum floor area per IBC 2012 Table 503:35,000 sq.ft.

California Building Code 2012

Allowable construction type: I-A, I-B

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FIRE RESISTANCE RATINGS SUMMARY

IBC 2012 – Tables 601 & 602; code 715.1 & 716.5

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WHAT IF…?

DETECTION AND ALARM - OVERVIEW

Combination heat/ smoke detector

Backup power source

Horn Strobe Notification Appliance

Central monitoring station

Emergency Response

Fire alarm control panel

Automatic fire sprinkler system

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ALARM AND DETECTION – SYSTEM LAYOUT

TRUE NORTH

PLAN NORTH

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DETECTION RESPONSE – ANALYSISHEAT RELEASE RATES OF POTENTIAL FUEL LOADS

SOURCES: SFPE Handbook, 4th ed; AIAA 2000-0722

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HEAT DETECTOR RESPONSE – DETACT

Response Time = 53sHRR = 1250 kW

Input Parameters

DETACT Results

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Note: Sprinkler response time = 95sManual pull stations are requiredIs this layout cost effective?

NOTIFICATIONRequired NA sound level:

40 dB + 15 dB = 55 dB(15 dBA above ambient)

Requirement met using 99 dBA alarm (6 dBA Rule)

Required strobe candela intensity per NFPA 72, Table 18.5.5.4.1(b)

Note: EVACS is not recommended for this building

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EGRESS CAPACITY

EGRESS CAPACITY > TOTAL OCCUPANT LOAD = OK!

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PLAN NORTH

EXIT PLAN

DEAD END: 98 ft

Maximum travel distance: 225 ft (250 ft limit)

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DECISION MAKING DURING EGRESS

1. Recognition: Become aware of some danger. (smoke, alarm, seeing fire)

2. Validation: Gather more information (talk to others, look for smoke/fire)

3. Definition: Assess the threat, understand its seriousness

4. Evaluation: Decide how to respond (behaviors of others? Exit locations?)

5. Commitment: Take action

6. Reassessment: If necessary, take additional action. Stress levels rise.

NFPA Fire Protection Handbook, ed. 20

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EXPECTED EVACUATION TIME 16

Actual 1 story department store data

OCCUPANCY MAP 17

SYSTEM AREA MAP 18

SPRINKLER RESPONSE – DETACT

Response Time = 95sHRR = 4500 kW

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TYCO ELO-231Standard Spray Upright11.2 k-factor¾” orifice

PRESCRIPTIVE APPROACH SUMMARYSTRUCTURAL:• Fire resistance ratings

requirements are satisfied• Foams sprays, protective

membranes, concrete wraps if additional protection is required

A&D:• Heat/Smoke detectors not

required• Manual pull stations

o Occupancy > 500• Horn-strobes spaced to 68 ft

o 6 dB rule• Heat detection by sprinklers

o 53s vs. 95s response time

EGRESS:• Occupant load = 3,208• Egress capacity = 4,340• Total exit time = 4 min

SPRINKLERS:• 4 systems• Extremely high demand• Large orifice sprinklers• System redesign to lower

pressure and flow required from the source

• Pump with secondary water source if necessary

PERFORMANCE BASED DESIGN (PBD)

• Past vs. Future• Specific to building, location, occupancy, and use

NFPA 101 – Life Safety Code (LSC)Goals and Objectives – Prescriptive:

o Protection of occupants not intimate with initial fire development

o Improvement of survivability of occupants intimate with initial fire development

o Added benefit to non-fire emergencies and crowd movement

o Provide occupant protection during time to evacuate, relocate, or defend in place

o Maintain structural integrity

PBD - OVERVIEW• Meet prescriptive goals and objectives

• Limit exposure to “instantaneous or cumulative untenable conditions” (4 methods)

• Establish design specifications, inputs, assumptions, building safety features

• Determine design fireo Realistico Challenging with respect to initial fire location,

early rate of growth in fire severity, and/or smoke generation

• Design Fire Scenarios (8 Scenarios)

PBD FIRE SCENARIO• Performance Criteria: Method 2, LSC

o Complete building evacuation before hot gas layer extends less than 6 ftabove floor (ASET > RSET?)

• Design Scenario: Scenario 2, LSCo Ultrafast-developing fire in the

primary means of egress with interior doors open at the start of the fire

o Focus on reduction in number of means of egress

o Can all occupants escape before being exposed to smoke?

Design Fire: electronics section in front of primary entrance and exit

PBD – EGRESS: NFPA CALCULATION

Methodology and data from NFPA Handbook, 20th edition

Increase by 100: confusion, searching for new exit

Decrease to 0 due to inaccessibility

PBD – EGRESS: PATHFINDER• Calculation of movement time,

not including premovement time• 3208 occupants randomly

spread throughout room• Single doors: 36”• Double doors: 72”• Walls placed around tables,

displays, and racks as obstructions

• All interior doors open

FIRE BLOCKING EXIT

OCCUPANTS

t = 0s

PBD – EGRESS: PATHFINDER• Occupants moving toward doors• Jams occurring at doors

FIRE BLOCKING EXIT

OCCUPANTS

t = 30s

PBD – EGRESS: PATHFINDER• Most occupants have reached an

escape route

FIRE BLOCKING EXIT

OCCUPANTS

t = 60s

PBD – EGRESS: PATHFINDER• All occupants are experiencing

jamming at doors• Floor is completely cleared

FIRE BLOCKING EXIT

t = 120s

PBD – EGRESS: PATHFINDER• Very few occupants remain• Maximum egress time: 191s

t = 180s

PBD – EGRESS: PATHFINDER RESULTS

0

500

1000

1500

2000

2500

3000

3500

0 20 40 60 80 100 120 140 160 180 200

Occ

upan

ts

Time (s)

Occupants Inside Costco During Evacuation OBSERVATIONS• Evacuation complete 3.2 min after begins• Including 1.7 min maximum pre-movement

time and 1.2 factor of safety, total time = 5.3 minutes

• Close agreement with NFPA method results (5.5 min)

Note: linear evacuation rate supports egress time is limited by exit capacity of exits rather than travel time to exits

PBD – CFAST ENVIRONMENT & LAYOUT

MAIN ENTRY AND EXIT

SINGLE-WIDE AND DOUBLE-WIDE EMERGENCY EXITS AROUND PERIMETER

LOCATION OF FIRE

DETECTION DEVICES

DESIGN FIRE – FIRE INPUT PARAMETERSP6 FIRE

• Full scale test• 2 pallets of 12 boxed

computer monitors• 1m x 1m x 1m, side by side• Soot and CO yields from

polystyrene• Ignition using 50-200 kW

line burner• Modeled as t2 fire reaching

steady burning after 25s

SFPE Handbook – Table 3-1.51

PBD – DETECTION AND ALARM

0

100

200

300

400

500

600

700

0 5 10 15 20 25 30 35 40 45 50 55 60

Tem

pera

ture

(⁰C)

Time (s)

Heat Detector Temperatures in Design Fire - CFAST

Hot Gas

Heat Detector 1

Heat Detector 2

Heat Detector 3

Heat Detector 4

HEAT DETECTOR ACTUATION = 5s• Delay has negligible impact on 1.7 min

pre-movement time

PEAK HRR REACHED

STEADY STATE BURNING

DESIGN FIRE – CFAST SIMULATION

T = 0s T = 10s

• Plume develops quickly• Hot gas layer forms immediately

• Initial temperature at 22 ⁰C


• Peak HRR is reached• Temperature of hot gas layer

rapidly increasing• Interface height: 8.87m

T = 20s T = 30s

• Hot gas layer has reached ceiling• Smoke already gathering at the ceiling


• Smoke layer remains high• Interface height: 8.3m• Alarm and pre-movement time

periods have passed. Occupants are now moving to exits. Some have exited already.

T = 60s T = 120s

• Temperature of hot gas layer continues to increase

• Interface height: 8.67m


• Interface height: 7.32m• After 5 minutes, all occupants

have reached an exit and are evacuating

T = 240s T = 300s

• Average lower layer temperature increasing (29 ⁰C)

• Interface height: 7.63m


T = 330s

• All occupants have exited building• Final interface height: 7.18m• Final lower layer temperature: 32.2 ⁰C

0

20

40

60

80

100

120

140

160

180

200

0

1

2

3

4

5

6

7

8

9

10

0 60 120 180 240 300 360 420 480 540 600

Tem

pera

ture

(C)

Laye

r Hei

ght (

m)

Time (s)

Hot Gas Layer Height and Layer Temperatures in Design Fire 1 - CFAST Simulation

Layer Height Upper Layer Temperature Lower Layer Temperature

PERFORMANCE BASED DESIGN – SUMMARY

ASET > RSET: SUCCESS• Extremely rapid heat and smoke production offset by massive

volume of compartment• Impact of smoke development unlikely to put occupants at risk• Overall performance from life safety perspective: very good

ASSUMPTIONS• Sprinklers do not activate – demonstrate safe egress is possible given

worst case scenario• Peak HRR maintained during steady burning period

o Fuel source large enough to supply continuous burning for entire duration of building egress

• Occupants spread evenly to all available exits during egresso If gathering occurs near one exit with another exit available,

occupants travel to available exit

CONCLUSIONPrescriptive requirements for structural design, alarm and detection system, egress, and sprinkler system were considered.

• Structural, A&D, egress requirements were satisfied• Recommendations made for sprinkler compliance (system

redesign, pump, secondary water source)

Performance-based analysis using Pathfinder egress modeling software and CFAST 7 with real-life (albeit, exaggerated) fire test data showed that the life safety criteria of ASET>RSET was satisfied with large margin, even with highly challenging design fire.

RECOMMENDATIONS• Determine if pump is required for sprinkler system• Examine impact of staff trained to help with egress

• Explore more complex modeling in Pathfinder: response times, seeking new exits, travel speeds

• Compare CFAST and FDS smoke height interface results• Performance based design for protection of property and valuables

FDS to model alternative suppression systems, examine cost impact

THANK YOU!

COSTCO, SAN FRANCISCO - Cal Poly

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