Central Whidbey Island Fire & Rescue Serving Coupeville, Greenbank, & Central Whidbey Island Ventilation Controlled Fires Fire Development and Potential for Extreme Fire Behavior CentralFire Department Whidbey Island Fire Instructor’s & Rescue ConferenceProfessionalism (FDIC) ● Integrity 2011 ● Compassion ● Excellence REV 1.0 Central Whidbey Island Fire & Rescue Whidbey is a large island in the Puget SdSound (North west WhiWashington ) CWIFR is a combination department serving 50 mi2 (129 km2) from four fire stations Predominant fire risks in this rural district are private dwellings and small to mid‐size commercial occupancies Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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 has thoroughl y mastered this combinati on of theory and practice. Fire Protection, 1876 Sir Eyre Massey Shaw Chief, London Fire Brigade Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Overview Compartment Fires Fire Development Burning Regime Vent Controlled Fires EtExtreme Fire BhBehav ior UL Tactical Considerations Practical Applications Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Compartment Fire A compartment is an enclosure such as a room within a building The term compartment fire is also used for fires involving multiple compartments Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Building Factors Area Fire Compartmentation Size Load Required Fire Flow Type Stories Height Mass Fuel Ceiling Structural Contents Construction Ventilation Profile Non Structural Thermal Building Openings Properties Actual Potential Fire Protection Normal Systems HVAC Ventilation Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.00.1 Fire Load MJ/kg The mass and burning 40 characteristics of the fuel encountered in compartment 30 fires has changed over time. 20 10 Fuel Load 1942 1980 Wood Polystyrene Low 9.9 kg/m2 29.3 kg/m2 2 2 Polyurethane Polyethylene High 64.4 kg/m 125.5 kg/m Foam Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Compartmentation Fire develops more quickly in a small compartment. Highly compartmented buildings may slow fire spread. Large compartments contain more air and may have a substantial fuel load. Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Ventilation Profile Existing and Potential Openings Normal building ventilation and compartmentation Ventilation openings created by exiting civilian occupants Tactical action taken by firefighters Unplanned ventilation All changes to the ventilation profile may influence fire behavior! Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Basic Considerations Under given conditions, compartment fires behave consistently Staffing has no impact on fire didynamics Context is critical! Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Basic Considerations Fuel Characteristics Compartmentation Ventilation Profile Firefighters have two primary strategies to influence fire behavior (fire control & ventilation) Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Fire Dynamics NIOSH F2010‐10 Ensure that the incident commander and firefighters understand the influence of ventilation on fire behavior Consider developing more comprehensive training requirements for fire behavior FF/EMT‐P Brian Carey (Fatality) FF/EMT‐P Kara Kopas (Injured) in NFPA 1001 and NFPA 1021. Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Building Blocks for Understanding Stages of Development . Incipient . Growth . Fully Developed . Decay Heat Release Rate ()(HRR) Burning Regime . Fuel Controlled . Ventilation Controlled Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Stages of Fire Development HRR Incipient Fully Growth Developed Decay Time Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Stages of Fire Development The stages dibdescribe a complex process. Multiple influencing variables are involved. Fire development can vary from this simple sequence Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Burning Regimes Fuel Controlled Fire growth is predominantly limited by the fuel availability and characteristics Ventilat ion ClldControlled Fire growth is predominantly lim ite d by availa ble oxygen Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Fuel and Power Key Concepts The chemical content of fuel influences heat of combustion and heat release rate (HRR). Heat of combustion is the total amount of energy released when a specific amount of fuel is oxidized. Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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. Units of Measure Energy Joules (J) Btu Power Watts (J/s) Btu/s Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Heat Release and Oxygen Key Concepts Oxygen Consumption 13.7 MJ/kg of O2 21% O2 in Air 3.00 MJ/kg of Dry Air 3.60 MJ/m3 of Dry Air William Thornton (1917) The Relation of Oxygen to the Heat of Combustion of Organic Compounds Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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 Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Heat Release Rate Key Concepts Heat release rate (HRR) is the driving force for the fire. Room temperature and concentration of toxic combustion products are correlated with HRR. High HRR indicates a high threat to life. Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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) Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Visualization Visualize packages of fuel materials in terms of heat of combustion and potential peak HRR 770 MJ Heat Release 3003.00 MW Peak HRR Wood and Polyurethane Sofa 51.3 kg (113 lbs) Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Visualization HRR (kW) 4000 3000 2000 1000 0 0 300 600 http://www.fire.nist.gov/fire/fires/fires.html Time (s) Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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. Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 What is Smoke Product of incomplete Smoke is Fuel! combustion & pyrolysis Complex aerosol (gas, vapor, particulate) Toxic and flammable Fluid that can transfer energy (conv ectio n aadnd radi ati on ) Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Upper Layer Hazards As a fire grows hot smoke Smoke is Fuel forms a layer above the cooler air below. This upper layer presents several hazards. RditRadiant and CtiConvective Heat Flux . Readily ignitable gas phase fuel Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Contemporary Fire Development HRR Fuel Ventilation Controlled Controlled Ventilation Increased Time Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 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! Central Whidbey Island Fire & Rescue Professionalism ● Integrity ● Compassion ● Excellence REV 1.0 Phenomena that result in rapid Extreme Fire Behavior fire progression and present a significant threat to firefighters Rapid transition and Transient Events sustained increase in HRR Overpressure Ignition and rapid or Confined explosive combustion Smoke BkdftBackdraft Explosion Step Events Pre‐Mixed High Fuel/Air