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PREINCIDNET PREPARATION. Properly calculate required fire flow for structures using the National Fire Academy Fire Flow Formula. FIRE FLOW REQUIREMENTS FIRE FLOW FORMULA. OBJECTIVES. Module 5 Overview. Given the required fire flow for a structure, estimate the personnel
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Properly calculate required fire flow for structures using the National Fire Academy Fire Flow Formula. FIRE FLOW REQUIREMENTS FIRE FLOW FORMULA OBJECTIVES Module 5 Overview
Given the required fire flow for a structure, estimate the personnel required for offensive operations. RESOURCE CAPABILITY AND DISTRIBUTION DATA OBJECTIVES Module 5 Overview
Given a scenario, properly complete a National Fire Academy Quick Access Prefire Plan QUICK ACCESS PREFIRE PLANNING OBJECTIVES Module 5 Overview
FIRE FLOW REQUIREMENTS • Fires extinguished by absorbing the heat with water • Application of water will: • Absorb heat • Reduce temperature • Extinguish fire
FIRE FLOW REQUIREMENTS To extinguish a fire , the quantity of water (gpm) must exceed the heat (Btu’s) being produced.
FIRE FLOW FORMULAQUICK CALCULATION Basic Formula: Length x Width = GPM 3
CALAULATES THEORETICAL FIRE FLOW • Large amounts of heat absorbed • Reduces temperature below ignition temperature • Fire is “blacked-out” ready for overhaul
WITH HIGH PERCENTAGES OF INVOLVEMENT INTERIOR OPERATIONS ARE NOT POSSIBLE • 100% involvement answer is theoretical • Starting point for realistic flow rate • Starting point for defensive operations • Tactical operations must be evaluated
ORIGIN OF FORMULA Empirical formula developed by NFA development team. Study of fire flow at fire situations
BASIC FORMULA Basic Formula: L x W = GPM 3 Flow for one floor fully involved. Estimate Length/Width to nearest 10 feet. Multiply L x W then divide by 3. Theoretical fire flow for 100% involvement.
BASIC FORMULA • Quick calculations at the scene • Calculates water required for: • Confinement, Extinguishment, Back-up lines
MULTIPLE STORIES Multiply base fire floor by number of floors
Insert 2 story house (50 ft X 30 ft /3) x 2 = FULLY INVOLVED = 1000 GPM 50% INVOLVED = 500 GPM 25 % INVOLVED = 250 GPM
EXPOSURES GPM = LENGTH X WIDTH + EXPOSURES 3
WATER FOR EXPOSURE PROTECTION • Interior exposures - floors above the fire on “fire-resistive” construction • Exterior exposures - buildings or other objects
EXPOSURE PROTECTION • Up to 4 floors above the fire • Buildings or other objects • 0 to 30’ -- usually an exposure • 30’ to 100’ -- could be an exposure • 100’ or more -- usually not an exposure
You must make the final determination of exposure based on observed conditions
EXPOSURE PROTECTION • Fire area adjacent to a fire wall • Should the exposure become involved - calculate flow as new fire building
EXPOSURE PROTECTION Exposure “C” 25% Exposure “B” Fire Exposure “D” 25% Building 25% Exposure “A” 25%
Exposure Fire Building Exposure “B” “D” Base Flow = 1000 GPM Exposure “B” = 250 GPM (25%) Exposure “D” = 250 GPM (25%)
INTERIOR EXPOSURE( Fire Resistive Structure) 5 EXPOSURE 25% 4 EXPOSURE 25% 3 EXPOSURE 25% 2 EXPOSURE 25% 1 FIRE FLOOR
25% Exposure “B” 250 gpm 25% Exposure “D” 250 gpm EXPOSURE PROTECTION “Fire Resistive” Structure 3 Exposure 250 gpm (25%) 2 Exposure 250 gpm (25%) 1 Fire Floor Total Fire Flow = 1000 GPM Total Exposure Flow = 1000 GPM Total Flow Required = 2000 GPM
PERCENTAGE OF INVOLVEMENT GPM = L x W + EXPOSURE x PERCENT OF INVOLVEMENT 3
PERCENTAGE OF INVOLVEMENT Fire Building Exposure “D” 1000 GPM 250 GPM (25%) 100% Involvement = 1250 GPM 75% Involvement = 950 GPM (1250 x .75) 50% Involvement = 625 GPM (1250 x .50) 25% Involvement = 325 GPM (1235 x .25)
Individual Activity 5.1 Fire Flow Calculation
15’ 20’ Fire building is 30’x 50’ Exposure B 15’ Fire Building 20’ Exposure D
KNOW INITIAL ATTACK CAPABILITY • Measured in terms of ability to flow GPM • If fire flow requirements exceed resources, get help
RESOURCE CAPABILITY AND DISTRIBUTION DATA • Capability/Distribution evaluation parameters • Requires an aggressive interior fire attack
INTERIOR FIRE ATTACK FLOW RATES AND PERSONNEL REQUIRED Hose size Flow Rates Personnel/Lines 1-1/2” 100 gpm 2 1-1/2” 150 gpm 2 1-3/4” 150 gpm 2 2” 240 gpm 3 2-1/2” 300 gpm 4+
FOUR MAJOR FUNCTIONS ON THE INCIDNET SCENE • COMMAND • VENTILATION • SEARCH • FIRE CONTROL
Insert building fire 40’ x 90’ slab foundation “Distribution at simple incidents”
FIRE INVOLVEMENT 1-story structure 40 x 90 (3600 Sq. Ft) built on a slab 25% involvement, no exposures gpm = 300
Personnel Requirement Incident Commander 1 Ventilation 2 Primary Search/Fire Attack/ Pump Operation 7 Total Personnel Required 10
Distribution at complex incident Insert 2 story building fire - lot’s of fire-Titled- distribution at complex incident 60 X 60
FIRE INVOLVEMENT 2-story structure 60 x 60 (3600 Sq. Ft) built on a slab 25% involvement, 1 second floor exposure gpm = 600
Incident Commander 1 1st and 2nd Floor Supervisors 2 Ventilation 4 Primary Search/Fire Attack/ Pump Operation 4- 1-3/4” lines 12 Total Personnel Required 19
CONCLUSION gpm divided by personnel = gpm per person 300 gpm divided by 10 persons = 30 gpm per person
CONCLUSION gpm divided by personnel = gpm per person 600 gpm divided by 19 persons = 31.5 gpm per person
ANALYSIS The average fire flow on the incident scene in the United States ranges between 25 and 50 gpm per person engaged in fire control efforts, as stated in the charts above.
ANALYSIS If the fire flow is below 25 gpm/person, you are probably using 1 1/2” hose. Consider switching to 1 3/4” hose; or, you have counted people who are not doing any of the jobs (reserves).
ANALYSIS If the fire flow is greater than 50 gpm/person, you either have too few people doing ventilation and primary search; or you are using too few people on each hoseline. NO master streams allowed during interior attack.
PROACTIVE USE OF THE DATA Have each unit that responds report the number of personnel on board. Multiply your department’s average flow per person to get your total capability responding to this alarm.
PROACTIVE USE OF THE DATA What total flow for 10 personnel? What total flow for 15 personnel? What total flow for 20 personnel?
INTERIOR FIRE ATTACK AND PERSONNEL REQUIRED Hose size Flow Rates Personnel/Line 1-1/2” 100 gpm 2 1-3/4” 150 gpm 2 2” 150 gpm 2 1-3/4” 240 gpm 3 2” 240 gpm 3 2-1/2” 300 gpm 4+
Large Group Activity 5.2: Personnel Capability and Distribution Data