Fire growth: No sprinklers

Workbook Page2

Fire growth: Sprinklers present

Why Fire Sprinklers? 80% of fire deaths occur in the home Low probability, high consequence

event Over 4,000 people die each

year in home fires $$$ millions in property

damage Less than 2% of homes

contain sprinklers

Residential sprinkler benefits

Life safety

Residential sprinkler benefits

Property safetyConservationEnvironmental impact

Demand on FDFF safetyHousing density

Causes of house fires (%)

CookingMatchesArsonCigsHeatingElec

15

10

25

13

1522

Who Is Most At Risk In A Fire?

Sleeping occupants Small children and the elderly

Twice as likely to die as able-bodied adults

What Is Flashover? When ceiling temp reaches ~1,200°

F: Bottom of smoky layer

erupts into flame Everything combustible

ignites at once Can take as little as

five minutes

Heat Spread by Convection

Heat Spread by Convection

Most victims in post-flashover fires are remote from the room of origin

Residential Sprinklers & Demand on Resources Water:

9-12 GPM v. 200 GPM per line. Apparatus & personnel:

Fewer critical tasks = fewer resources.

Organization: Can be EMS-oriented v. suppression-

oriented.

Critical fireground task A task that must be performed

simultaneously, or in a highly coordinated manner, with other tasks.

Examples of critical tasks Attack line and ventilation Attack line and water supply

Critical Fireground Tasks Task Personnel Assignment Attack 2 1st engine S & R 2 Ladder Co. Ventilation 2 As assigned Backup line 2 2nd engine Safety 1 As assigned Pump oper. 2 Each engine Water supp. 1 2nd engine Command 1 District chief

Sprinkler v. manual suppression 30-90 seconds

after flames 13 GPM @ 10 PSI Very little has

burned Room of origin

still tenable to life Operates

automatically

8-15 minutes after report

200 GPM @ 100 PSI A lot has burned Entire home

untenable to life Someone needs to

call fire department

Sprinkler v. fire department

Sprinkler Operates whether

you can take action or not Elderly, bedridden,

children Operates whether

you are there or not Asleep, in another

room, in yard, away

Fire department Firefighters can’t

respond until someone calls

Fire can burn unnoticed until it breaks out of house

Why sprinklers? Builders build safe homes – then

people move in Houses don’t catch fire, contents do Contents loaded with synthetic

material Burn twice as hot, twice as fast

Homes are tight for energy

Why FD’s want sprinklers Can’t respond in time to save lives

Content fires go to flashover in 5 minutes or less

Occupants start dying halfway to flashover

Occupants who can’t get out under own power twice as likely to die The young, elderly

Smoke alarm limits In house fire where deaths

occurred, over 40 percent of the homes had working smoke detectors

Occupants often disable smoke alarms to prevent nuisance alarms

Sprinkler effectiveness Smoke detectors by themselves

less than 50 % effective Smoke detectors + sprinklers

increase survival rates to 97% Based on long-term studies in Napa

CA, Prince Georges County MD, Scottsdale AZ

Why sprinklers are effective Quick acting (30-60 seconds after

flames visible) Fire is small and containable

Stop spread of smoke and flame before flashover

Control fire with 10-15 GPM v. 200 GPM from fire hose

Sprinkler experience Zero lives lost in sprinklered homes

Scottsdale, AZ Napa, CA Prince George’s County, MD

Property damage (including water damage) nine times less

Fire departments handle with fewer stations and firefighters

Before 13D NFPA 13 was the only standard Categorizes buildings by “hazard class”

Fire load, rate of heat release, peak heat release

Uses area v. density to determine water flow As hazard class increases, density and

coverage area increase Higher hazard = more GPM, more sprinklers

Additional gallonage for fire hoses

NFPA 13 Area/Density curves

Density and area coverage Function of orifice size and

pressure. Orifice size indicated by K factor.

Examples - 3.0, 3.9, 4.2, 5.6. The higher the K factor, the larger

the orifice.

Lower pressure = smaller area

Higher pressure = larger area

Use of higher pressure Sprinklers with the same orifice

size can cover wider areas with the same density

Reliable RES 16, 3.0 K factor 9 GPM over 12 x 12 area at 9 PSI 10 GPM over 14 x 14 area at 11.1 PSI

Both supply .04 GPM per sq. foot

Use of larger orifices Compared to a head with a smaller

K factor, one with a larger K factor supplies a higher density to the same area. 3.0 for 14x14 area flows 10 GPM at

11.1 PSI. 3.9 for 14x14 area flows 12 GPM at

9.5 PSI.

Hydraulically most remote The hydraulically most

“demanding” At the minimum required flow, the

sprinkler that causes the highest drop in pressure from the street

Not the geographically most remote on gridded systems Water enters grid at different points

NFPA 13D

Installation of Sprinkler Systems in One- and Two-Family Dwellings

and Manufactured Homes

NFPA 13D’s beginnings “America Burning” published in

1973 US leads in fire deaths. Most fire deaths occur in homes.

NFPA 13 committee formed residential sub-committee to investigate sprinkler protection.

Format of 13D 1 - General information. 2 - Water supply. 3 - System components. 4 - System design. 5 - Limited area dwellings. 6 - Referenced publications. App. A - Explanatory material App. B - Referenced publications.

13D objectives Limit maximum ceiling temp to

600°F. Limit temp at 5’ 3” to 200°F. Prevent flashover and keep room of

origin tenable to life for 10 minutes. Attain objectives with no more than

two sprinklers operating, with density of .04 GPM/sq. foot.

No minimum area requirement.

Committee recommendations System can be slightly less reliable,

with fewer operational features, and be effective

Must be substantially less expensive Primary goal: life safety Secondary goal: property safety Should control fire for sufficient

escape time – 10 minutes

Recommendations Piping, components, hangers must

be compatible with residential construction techniques

Combined sprinkler/plumbing systems are acceptable from a fire protection standpoint

Sprinklers can be omitted in areas of low incidence of fire deaths

First edition of 13D in 1975 Based on relatively limited scientific

understanding of residential fires and how sprinklers should protect against them

Applied technology that was applicable to property protection or commercial, industrial occupancies

Was not cost-effective but spurred research and development

Full scale tests Discharge rates Spray patterns Response sensitivity Design criteria Ability to maintain tenability to life

for escape time

Goal: Tenability in room of origin Carbon monoxide concentration

3000 PPM Temperature at breathing level

200°F Oxygen depletion

1980 edition Based on better understanding of

residential fires Had a new class of sprinkler Based on different method for

calculating minimum water flow

Criteria for residential sprinklers Prevent flashover.

Turning point in fire for victims, firefighters

Maintain 200oF at eye level Temperature is survivable near the floor 150oF of moist air will prevent breathing

Control fire with one or two sprinklers Allows smaller water supply

Sprinkler incentives Narrower streets Smaller setbacks Smaller water mains Fewer fire hydrants Fewer fire stations

WHAT LIES AHEAD

10-20 GPM v. 200 GPM

Fire threat, 1-2 family homes Sleeping occupants Small children, elderly and no

special exit arrangements Cooking facilities Smoking Unprotected vertical openings

House fires A low probability event, but a

high-consequence event A reasonably expected risk in this

community

Flashover is the enemy

Flashover - all exposed surfaces in room ignite almost simultaneously

Flashover description - flames out the door of room of origin

Time to flashover dictated by rate of heat release Synthetics burn twice as hot, twice as

fast

Time to flashover Measured from time of flaming

stage A large portion of fires go to flaming

stage quickly Smoldering stage nearly always

progresses to flaming May not produce much hot smoke

until shortly before flaming

Fire cause and time to flashover Unattended cooking Very quickly (25-30 %) Playing with matches Very quickly (13 %) Arson (15%) Very quickly Smoldering cigarette Minutes-hour (20-25%) Heating (15%) Minutes Electrical (10-12%) Minutes-hour

Most victims in post-flashover fires are remote from the room of origin

Home fires by victim location& extent of flame damage

Flames

Victim Location Room of origin Beyond ROO

Intimate 7.3% 10.1%

In room - not intimate

6.1% 17.9%

Not in room 6.1% 51.5%

Unclassified 0.4% 0.6%

Residential Sprinkler Characteristics Fast response

30-60 seconds v. 120-180 seconds for commercial sprinklers

Discharge pattern Hits wall at 12” below ceiling

Prevents flashover in room of origin Reduces number of critical

fireground tasks

… characteristics.

Responds before room of origin becomes untenable to human life

Tenability: Eye-level temp > 150oF, moist air CO > 3000 ppm Smoke > .5 Optical Density/m

House fire at 4842 Oak Street Two-story home Fire in kitchen Source - Electric heater Material ignited - synthetic-lined

drapes, spread to cabinets and cupboards

Residential fires 23 % of fires 80 % of fire deaths 75 % of fire injuries

Events after discovery Family sleeping in upstairs bedrooms Parents awakened (maybe smoke

alarm). Mother saw incipient fire, called 911 Smoke, heat blocked mother from

returning upstairs, she escaped through front door

Father rescued two sons, could not reach third

One fatality, four injured

Fire growth Flashover occurred 4 minutes after

flaming stage Untenable in 2 minutes

Fire department arrived 4-5 minutes after call

Victim died of CO poisoning

Witness statements confirm model results Mother’s description

Saw curtains on fire Grabbed extinguisher, fire too large Went to living room to call 911 Tried to go back upstairs, stopped by

smoke/heat Neighboring firefighter’s description

Saw fire in kitchen as he started across street In seconds, flames were out front door

If sprinklers had been installed

No sprinkler

Untenability in 123 seconds (smoke, heat, O2)

Flashover in 4 minutes, 8 seconds

Sprinkler present

Sprinkler operated in 68 seconds

Ceiling temp = 250F Not enough smoke,

heat, CO to make room untenable