1. Principles of Fire Behavior
Additional information for MINA
Principles of Fire Behavior; James G. Quintiere; Delmar Publishers; ISBN

2. What is Fire?
An uncontrolled chemical reaction producing light and energy sufficient to damage skin
Also identified as combustion – a chemical reaction involving fuel and an oxidizer in the air
Think kilowatts
Will there always be light in a flame? No, e.g., burning of hydrogen with air or oxygen produces only water vapor from the reaction.
Chemical reaction -

3. Natural Causes of Fire Lightning Extreme weather Earthquake
Key for the investigator
Lightning greatest natural cause
Winds can cause power lines to fall as will ice storms
Earthquakes interrupt power and fuel sources

4. Man Made Causes Open flames Explosive environments Inattention
Chemical reactions
Whether unintentional or intentional, uncontrolled fires will happen that will cause damage – Great Fire of London; Chicago Fire; Others
Explosive environments would include the grain bins, wood or carpentry areas; metal shops; paint shops; others

5. Types of Fires Diffusion flames Smoldering Spontaneous combustion
Premixed flames

6. Diffusion Flames
A combustion process in which the fuel gas and oxygen are transported into the reaction zone due to concentration differences – Fick’s Law
Move from high to low concentration in the mixture
Natural flaming fires are diffusion flames
Match or candle

7. Diffusion Flames Terms identifying diffusion flames
Pyrolysis – decomposition process as in wood
Laminar – pure molecular diffusion as in a candle
Buoyancy – gravity or lack of gravity with hotter or lighter gases
Jet flame – high pressure created by gaseous fuel sources

8. Smoldering Slow combustion process Charring - >1000 degrees
Solid fuel source
Produces deadly levels of carbon monoxide
Examples
Cigar
Upholstered chair
Charcoal grill
You are investigating a base housing fire. The military member was found in the fire burned. First question would be to ask why didn’t the guy get out when the chair he was setting in caught fire? He falls asleep with his cigarette in hand. It falls in the chair and begins to smolder. Massive amounts of CO is created, incapacitating him before the chair finally ignites.

9. Spontaneous Begins with a slow oxidations in a fuel exposed to air
Very little heat lost
Thermal runaway
Examples
Haystacks
Sawdust bin
Oily rags piled

10. Premixed Flames Mixing of fuel gas and air or oxygen
Mixed before ignition and propagation
Controlled would be jet engines and oxyacetylene torch
Uncontrolled examples
Confined space
Methane leak

11. Premixed Flames Concentration limits
Gaseous fuels will ignite within limits
Upper (UFL)
Lower (LFL) – temperature just before fuel condenses to a liquid at the LFL is call the flashpoint
Autoignition temp (AIT) – lowest temp to cause spontaneous ignition

12. Heat Transfer Conduction – a molecular phenomenon
Convection – conduction in a moving fluid
Radiation – an electromagnetic phenomenon
Heat Flux – the flow rate of heat – key to assessing the potential damage by a fire
A lot of formulas necessary to determine the type of fire and how heat is transferred.
In this subject there is the discussion of flashover. This is an evet that can occur at a some temerature of 500 to 600 degrees C in which flames will suddenly fill a room. (page 61)

13. Ignition
Piloted – process of initiation and flame propagation in premixed fuel systems – e.g., welding, jet engines, gas stoves
Autoignition – no spark or flame source

14. Ignition
Evaporation – the process of gas molecules escaping from the surface of a liquid
Humidity – higher the humidity, less evaporation in the air – lower, more
Flashpoint – temp of a liquid fuels and the LFL – point of piloted ignition
Boiling point – temp that liquid can evaporate under normal atmospheric conditions
What does the MSDS state for the product that was used in the mishap? What environment was the product used???

15. Flame Spread The process in which the perimeter of the fire grows
Wind aided
Opposed flow
Pyrolysis or vaporization region
Burning rate
Yes, as an investigator you need to understand how that flame spread like it did.
Fire spread – process of advancing a combustion front
Wind aided – air flow in the same direction as the fire spread
Opposed flow – air flow in the direction opposite to the fire spread
Pyrolysis – breaking up a substance into pther molecules as the result of thermal decomposition
Burning rate – the consumption of fuel mass per unit time
(page 84)
Natural flow – air flow induced by buoyancy (gravity)
Forced flow – produced by wind or a fan
(page 87)

16. Flame Spread Surface flame
Downward/lateral wall spread – opposed flow flame spread
Spread through porous solid arrays – brush/debris
Spread on liquids – viscous/surface tension
For the downward or lateral wall spread, this is when the surface temperature is above a critical value. When addressing what wall surfaces should be, this is a point of action. What is the room going to be used for and how do we need to protect the occupancy. Paints and wall covers can affect how a fire can spread.
Viscous – fluid friction
Surface tension – force within the surface of a liquid
Refer to ASTM E 162 and ASTM E 648 for the various tests that are conducted to determine flame spread of materials that are used in construction.
You are asked to evaluate a self help project. The project is putting up walls for an interior office and maintenance room. It has the required number of doors/exits and lighting is going to be wired by CE. What maintenance? What kind of wall surface? Is it adequate for the risks of the work being done in the room?

17. Burning Rate The mass of solid or liquid fuel consumed per unit time
Mass loss rate – the mass of fuel vaporized but not necessarily burned per unit time
This may not be a factor when investigating the mishap involving a fire, but when evaluating the scene, you will probably encounter mass loss rate or fuel that may not have burned.
An organization wants to use plexiglass instead of glass for the interior office they are building. From a fire safety standpoint, what is the concerns? What type of flame can be expected?
An exercise: take small wooden sticks (4x1/4x1/4) and in one stack pile with all the sticks in contact. The next pile leave 1/4in space between the sticks as you stack them. Which one burns? Which stack or pile had more surface exposed?

18. Fire Plumes
Turbulent fire plumes – the flame and gases emanating from a burning object
Buoyancy – effective force on fluid due to density or temperature differences in a gravitational field
Entrainment – the process of air or gases being drawn into a fire, plume or jet

19. Fire Plumes
Flame height – the vertical measure of the combustion region
Pool fires
Line fires
Eddies – rotating regions of a fluid
Vortex – a ring of eddies
Flame lengths – depends on energy released
There have been some major fires that were so intense because of the elements described in this section.
Petroleum and grain elevator fires are known for the intensity of the fire plumes.Pool fires involving horizontal fuel surfaces, usually symmetrical
Line fires are elongated on a horizontal fuel surface

20. Combustion Products Products – chemical compounds produced by fire
Yield – the mass of product produced per unit mass of fuel supplied
Concentrations – the percentage of material per unit mass (or volume) of its mixture
There are other terms that are discussed in the text but not important for the general investigation.

21. Concentration
The primary hazard of fire is the composition and associated concentrations of the smoke
Hazards
Vitiation – reduction in oxygen
Narcotic gases – narcosis
Irritant gases – acid, hydrocarbon byproducts
Smoke visibility
Hyperthermia – heat stress
Page 157

22. Compartment Fires Stages of fire development Developing fire Flashover
Fully developed
1. Developing fire – Following ignition, the fire grows on an item and may involve other items. Behaves as if it is burning in the open air for the most of the period.
2. Flashover – dramatic increase in fire conditions due to the confinement of the room.
rapid ignition due to heat flux increasing
Accumulation of fuel rich gasses and their sudden exposure to air – backdraft
The increase in the burning rate and sudden extension of flames
(See page 170)
Other terms that will be found in the flashover: Ventilation-limited and ventilation-controlled.
3. Fully developed – flames fully encompassing the room, flames, fuel involved is a maximum potential.

23. Compartment Flow Dynamics
Layers and vent flows
Smoke filling
Smoke movement

24. Fire Analysis Fire safety design Detection and design
Mitigation of growth and suppression
Egress
Continuity of operations
Structural integrity
Refuge and rescue

25. Resources Firedynamics.com www.campusfire.org www.campusfiresafety.com

26. Resources American Fire Journal Fire House Fire Chief Fire Engineering
Fire Technology
USFA – Fire Data Analysis Handbook
USFA FDA Handbook free download – good reference
ISFTA – Pubs for refiew