Ventilation Controlled Fires - CFBT-US!

Central Whidbey Island Fire & Rescue 

Serving Coupeville, Greenbank, 

& Central Whidbey Island 

Ventilation Controlled Fires 

Fire Development Development and Potential 

for Extreme Fire Behavior 

Central Fire Department Whidbey Island Fire Instructor’s & Rescue Conference Professionalism (FDIC) ● Integrity 2011 

● Compassion ● Excellence REV 1.0


� Whidbey is a large island in the Puget 

SSound d(N (Northwest h Washington) 

W hi ) 

� CWIFR is a combination department 

serving 50 mi2 (129 km 2 ) from four fire 

stations 

� Predominant fire risks in this rural district 

are private dwellings and small to mid mid‐size size 

commercial occupancies 

Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence 

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Philosophy 

In order to carry on your business properly, it is 

necessary for those who practice it to understand 

not only what they have to do, but why they have 

to do it… 

No fireman can ever be considered to have 

attained a real proficiency in his business until he 

h has thoroughly th hl mastered t d this thi combination bi ti of f 

theory and practice. 

Fire Protection, 1876 

Sir Eyre Massey Shaw 

Chief Chief, London Fire Brigade 


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Overview 

� Compartment Fires 

� Fire Development 

�� Burning Regime 

� Vent Controlled Fires 

�� Et Extreme Fire Fi Behavior Bh i 

� UL Tactical Considerations 

� Practical Applications 


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Compartment Fire 

The term compartment fire is 

also used for fires involving g 

multiple compartments 

A compartment is an 

enclosure such as a 

room within a building 


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Building Factors Area 

Structural 

Non 

Structural 

Thermal 

Properties p 

Type 

Fuel 

Construction 

Mass 

Fire 

Protection 

Systems 

Fire 

Load 

Contents 

Required 

Fire Flow 

Building 

HVAC 

Size 

Compartmentation 

Height 

Ventilation 

Profile 

Normal 


Stories 

Ceiling 

Openings 

Actual Potential 


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Fire Load 

The mass and burning 

characteristics of the fuel 

encountered in compartment 

fires has changed over time. 

Low 

High 

Fuel Load 

1942 1980 

9.9 kg/m 2 

64.4 kg/m 2 

29.3 kg/m 2 

125.5 kg/m 2 

MJ/kg 

40 

30 

20 

10 

Wood Polystyrene 

Polyurethane 

Foam 


Polyethylene 

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Compartmentation 

� Fire develops more 

quickly in a small 

compartment. 

�� Highly compartmented 

buildings may slow fire 

spread. p 

� Large compartments 

contain more air and 

may have a substantial 

fuel load. 


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Ventilation Profile 

Existing and Potential Openings 

� Normal building ventilation and 

compartmentation 

� Ventilation l openings created d bby 

exiting civilian occupants 

� Tactical action taken by y 

firefighters 

� Unplanned ventilation 

All changes to the ventilation profile 

may influence fire behavior! 


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Basic Considerations 

� Under given conditions, 

compartment fires 

behave consistently 

� Staffing has no impact 

on fi fire dynamics d i 

� Context is critical! 


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Basic Considerations 

� Fuel Characteristics 

� Compartmentation i 

�� Ventilation Profile 

Firefighters have two primary strategies to 

influence fire behavior (fire control & ventilation) 


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Fire Dynamics 

NIOSH F2010‐10 F2010 10 � Ensure that the incident 

FF/EMT‐P Brian Carey (Fatality) 

FF/EMT‐P Kara Kopas (Injured) 

� Ensure that the incident 

commander and firefighters 

understand the influence of 

ventilation on fire behavior 

�� Consider developing more 

comprehensive training 

requirements q for fire behavior 

in NFPA 1001 and NFPA 1021. 


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Building Blocks for Understanding 

� Stages of Development 

� Incipient 

� Growth 

� Fully Developed 

� Decay 

� Heat Release l Rate (HRR) ( ) 

� Burning Regime 

� Fuel Controlled 

� Ventilation Controlled 


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Stages of Fire Development 

HRR 

Incipient 

Growth 

Fully 

Developed Decay 


Time 

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Stages of Fire Development 

�� Th The stages t ddescribe ib a 

complex process. 

� Multiple influencing 

variables are involved. 

� Fire development can vary 

from this simple p sequence q 


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Burning Regimes 

�� Fuel Controlled 

Fire growth is predominantly 

limited by the fuel availability 

and characteristics 

� Ventilation il i Controlled C ll d 

Fire growth is predominantly 

li limited i d bby available il bl oxygen 


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Fuel and Power Key Concepts 

� The chemical content of fuel influences heat of 

combustion and heat release rate (HRR) (HRR). 

� Heat of combustion is the total amount of energy 

released when a specific amount of fuel is oxidized. 


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Fuel and Power Key Concepts 

� Power is an amount of energy 

delivered over a specified time 

�� Heat release rate (HRR) is the 

energy release per unit of time. 

Energy 

Power 

Units of Measure 

Joules (J) 

Watts (J/s) 

Btu 

Btu/s 


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Heat Release and Oxygen Key Concepts 

Oxygen Consumption 

� 13.7 MJ/kg of O 2 

�� 21% O 2 iin Ai Air 

� 3.00 MJ/kg of Dry Air 

� 3.60 MJ/m 3 of Dry Air 

William Thornton (1917) 

The Relation of Oxygen to the Heat 

of Combustion of Organic Compounds 


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Heat Release and Oxygen Key Concepts 

The door should be kept shut 

while the water is being brought, 

and the air excluded as much as 

possible, as the fire burns 

exactly in proportion to the 

quantity of air which it receives. 

James Braidwood (1866) 

Fire Prevention and Fire Extinction 


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Heat Release Rate Key Concepts 

�� Heat release rate (HRR) is the 

driving force for the fire. 

�� Room temperature and 

concentration of toxic 

combustion products p are 

correlated with HRR. 

�� High g HRR indicates a high g 

threat to life. 


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Heat Release Rate Key Concepts 

HRR varies over time, increasing as 

more fuel becomes involved and then 

falling as fuel is consumed. 

HRR (kW) 

kW 

Time (s) ( ) 


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Visualization 

Visualize packages of 

fuel materials in terms 

of heat of combustion 

and potential p ppeak 

HRR 

Wood and Polyurethane Sofa 

51.3 kg (113 lbs) 

770 MJ Heat Release 

300MW 3.00 MW Peak HRR 


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Visualization 

HRR 

(kW) 

4000 

3000 

2000 

1000 

0 

0 300 600 

Time (s) 

http://www.fire.nist.gov/fire/fires/fires.html 


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Incomplete Combustion 

What happens if the fuel is 

not completely oxidized 

during combustion? 

Incomplete combustion results in production of carbon 

monoxide, carbon particulate and a wide range of 

other substances (depending on the fuel) as well as 

accumulation of unburned pyrolysis products. 


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What is Smoke 

� Product of incomplete Smoke is Fuel! 

combustion & pyrolysis 

� Complex p aerosol (g (gas, vapor, p 

particulate) 

� Toxic and flammable 

� Fluid that can transfer energy 

(convection (co ect o aand dradiation) ad at o ) 


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Upper Layer Hazards 

� As a fire grows hot smoke 

forms a layer above the 

cooler air below. 

�� Thi This upper layer l presents t 

several hazards. 

� RRadiant di tand d Convective C ti 

Heat Flux 

�� Readily ignitable gas 

phase fuel 

Smoke is Fuel 


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Contemporary Fire Development 

HRR 

Fuel 

Controlled 



Ventilation Increased 

Time 


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Extreme Fire Behavior Phenomena 

�� Flashover 

� Backdraft 

� Smoke Explosion 

� Flash Fire 

Firefighters may be able to define these 

terms, but often miss key indicators of 

potential extreme fire behavior! 


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Extreme Fire Behavior 

Rapid transition and 

sustained increase in HRR 

Ignition and rapid or 

explosive combustion 

Step Events 

Fuel Ventilation 

Controlled Controlled 

Flashover 

Vent‐Induced 

Moderate Fuel/Air 

Concentration 

Flashover 

HRR Sufficient to Result in Full Surface 

Involvement 

Phenomena that result in rapid 

fire progression and present a 

significant threat to firefighters 

Smoke 

Explosion 

Pre‐Mixed 

Flammable 

Fuel/Air Concentration 

Transient Events 

Overpressure 

Confined 

Flash 

Fire 

BBackdraft kd ft 

High Fuel/Air 

Concentration 

Pre‐Mixed Flammable 

Fuel/Air Concentration 

Limited Mass or Confinement 

Minimal 

Overpressure 


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Extreme Fire Behavior Step Event 

HRR 

Fuel 





Time 


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Extreme Fire Behavior Transient Event 

HRR 

Fuel 





Time 


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Extreme Fire Behavior Ambiguous Events 

HRR 

Fuel 





Time 

What is This? 


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Experience 

� Washington DC ‐ Flashover 

� New York City ‐ Backdraft 

�� Duango CO ‐ Smoke Explosion 

� San Pablo CA ‐ Flash Fire 

CFBT‐US, LLC has developed case studies 

for each of these incidents. The cases 

can be downloaded at www.cfbt‐us.com 


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Washington DC Flashover 

May 30, 1999 

3146 Cherry Road NE 

Side A 

Firefighter Anthony Phillips 

Firefighter i fi h Lewis i Mathews 

h 


Side C 

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New York NY Backdraft 

March 28, 1994 

62 Watts Street 

Captain John Drennan 

Firefighter James Young 

Firefighter Christopher Seidenburg 

June 17, 2001 

12‐22 Astoria Boulevard 

Firefighter John J. Downing 

Firefighter Brian D. Fahey 

Firefighter Harry S. Ford 


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Durango CO Smoke Explosion 

January 22, 2008 

764 Main Street 

Nine Firefighters & Fire Officers Injured 


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San Pablo CA Flash Fire 

July 27, 2007 

148 Michele Drive 

Captain Mathew Burton 

Engineer Scott Desmond 


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UL Research: Lessons Learned 

Practical Application of 

Fire Dynamics Research 

Impact of Ventilation on Fire Behavior 

in Legacy & Contemporary 

Residential Construction 


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� Most fires beyond the incipient stage are 

vent controlled when we arrive 

� If vent controlled increased ventilation 

results increases HRR 

�� The entry point is a ventilation opening 

� Ventilation openings (including the entry 

point) i t) create t a flow fl path th 


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� Ventilation and fire attack must be 

closely coordinated 

� Tactical ventilation will not return the fire 

to a fuel controlled burning regime 

�� If the fire has self self‐vented vented it will grow 

quickly when ventilation is increased 

� A closed door maintains a more tenable 

environment in a compartment 


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� Water applied into the fire compartment 

from the exterior reduces HRR and does 

not push fire to uninvolved compartments 

� Low oxygen concentration limits flaming 

combustion in adjacent j compartments p 

(this can change with ventilation) 


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Situational Awareness 

� Recognize the hazards 

presented by ventilation 

controlled fires 

� Identify key fire behavior 

indicators and anticipate p 

fire development 

�� Be proactive in controlling 

the fire environment 


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Serving Coupeville, Greenbank, 

& Central Whidbey Island 

Chief Ed Hartin, MS, EFO, MIFireE, CFO 


1164 Race Road 

Coupeville, WA 98239 

ehartin@cwfire.org 

ed.hartin@cfbt‐us.com 

(360) 914 914‐7704 7704 

( (503) 03) 793‐1296 93 1296 

Central Fire Department Whidbey Island Fire Instructor’s & Rescue Conference Professionalism (FDIC) ● Integrity 2011 

● Compassion ● Excellence REV 0.1 1.0

Ventilation Controlled Fires - CFBT-US!

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