1. Chapter 5 Fire Behavior and Building Construction

2. Objectives
Identify fundamentals of fire behavior and key fire phenomena.
Describe the development of a compartment fire.
Identify the ways fire is influenced by a building and its characteristics.

3. Objectives
List the ways buildings and their components are affected by a fire.
Explain how specific building materials behave under fire attack.
Describe smoke behavior and the effects it can have on the building, occupants, and fire fighters.

4. The Basics of Fire and Fire Behavior
Fire requires four elements:
Fuel
Oxidizing agent
Heat
Uninhibited chemical chain reaction

5. The Basics of Fire and Fire Behavior
Three methods of heat transfer:
Conduction contact
Convection
Radiation
Courtesy of Richard Wolfson.
Courtesy of Glenn Corbett.

6. The Basics of Fire and Fire Behavior
Autoignition: a combustible material ignites spontaneously
Autoexposure: vertical spread of fire on the exterior of a multistory building

7. Compartment Fires Compartment: the enclosure around a fire
Four stages of a fire:
Incipient
Free burning
Flashover
Smoldering/ decay
Reproduced with permission from NFPA , Guide for Fire and Explosion Investigations, Copyright
© 2011, National Fire Protection Association. This reprinted material is not the complete and official position
of the NFPA on the referenced subject, which is represented only by the standard in its entirety.

8. Compartment Fires Elements of a compartment fire: Fire plume Smoke
Heated gases
Ceiling layer
Neutral plane

9. Compartment Fires Entrainment Flameover Oxygen supply
Wind-driven fires must be considered tactically.
Fire blanket
Courtesy of NIST.

10. Compartment Fires Construction factors influencing fire behavior:
Combustible interior finishes or walls
Vertical openings
Height of the fire room
Proximity of walls to each other
HVAC systems

11. Backdraft
Burning of heated gaseous products when oxygen is introduced into an environment whose oxygen supply has been depleted

12. Fire Behavior, Fire Fighters, and Buildings
Hazards in addition to collapse:
Flashover
Backdraft
Concealed fires
Rapid spread of fire
Ventilation
Abnormal situations warrant a thorough investigation.

13. Fire Growth and Spread
Growth and spread are influenced by building construction.
Combustible acoustical tile is fiberboard into which holes have been punched.
Courtesy of the NFPA.

14. Examples of Fire Growth and Spread
Rapid fire growth = serious losses of life
Combustible ceiling tiles suspended below the floor above = void for holding CO gas
Ignition of trapped CO gas = violent explosion

15. Building or Contents Hazard?
Fire growth building problems can be hidden or exposed.
Fire growth contents problems can be due to:
Furnishings
Interior finish/decorations
Mercantile stock
High flame-spread materials contribute to fire growth, smoke, and toxic products.

16. Hidden Building Contents
Batt insulation
Sprinklers may not reach a fire spreading above the ceiling.
Combustible fiberboard
Foamed-plastic insulation
Protected with a half-inch gypsum board covering
Electrical insulation

17. Interior Finishes Plaster
Interior finishes may increase fire hazard via:
Increasing fire extension
Generating smoke and toxic gases
Contributing to flashover
Low-density fiberboard
Cheap interior finish
Quick installation

18. Interior Finishes Combustible acoustical tile
Installed over the original ceiling
Industry opposition to regulation of interior finishes
NFPA opposition to fiberboard
Courtesy of Glenn Corbett.

19. Other Hazards Associated with Interior Finishes
Adhesives
High-density fiberboard
Paper
© Saxon/AP Images.

20. Other Hazards Associated with Interior Finishes
Fabrics
Cork
Rattan
Wood
© AP Images

21. Other Hazards Associated with Interior Finishes
Plastics
May be disguised as wood or glass
Ireland’s Tribunal of Inquiry
Architects may not recognize potential combustion problems.
© Norman Pogson/ShutterStock, Inc.

22. Other Hazards Associated with Interior Finishes
Worcester Cold Storage Warehouse Fire 1999
Carpeting
© Paul Connors/AP Images.

23. Additional Hazards Void spaces Remodeled ceiling hazards
Suspended ceilings of combustible tile form void spaces.
Remodeled ceiling hazards
Removal of old ceilings is not required.
Courtesy of the estate of Francis L. Brannigan.

24. Additional Hazards Aircraft interiors Acoustical treatment
Aircraft built after 1990 have to meet stricter FAA standards.
Acoustical treatment
Open-plan offices create a potential hazard.
Corridors
© bhowe/ShutterStock, Inc.

25. Additional Hazards Alterations Decorations and contents
Major fire hazards
Christmas trees
Haunted houses
Glass fiber-reinforced plastic

26. Today’s Fire Loads
Fire loads and rates of heat release are greater today than when fire codes were first written.
First Interstate Bank Fire
Hotel remodeling
Regulations
California
Boston
Port Authority of New York and New Jersey

27. Today’s Fire Loads Certification of interior designers
Residential fire tests
Report on NBS 1980 residential fire tests
NFPA movies
Fire: Countdown to Disaster
Fire Power

28. Control of Rapid Fire Growth
Eliminate high flame spread surfaces
Separate the material from the source of combustion
Cut off the extension
Coat the material
Fire-retardant surface coatings
Pressure-treated, fire-retardant wood

29. Products of Combustion
Smoke
Airborne solid and liquid particulates produced by a fire
CO, hydrogen cyanide (HCN), and carbon dioxide
More damage to property than fire or water

30. Products of Combustion
Smoke Gases
Cause injury or death when inhaled or absorbed
Concentration and exposure time
1929 Cleveland Clinic Fire
Polyvinyl chloride (PVC)
Courtesy of the National Board of Fire Underwriters/NFPA.

31. Gas Flammability CO is a flammable gas.
Combustion leads to flashover or backdraft.
Gases accumulate in enclosed areas.
Ventilation does not prevent CO explosions.

32. Physical Effects of Smoke
Different physical effects on people
CO is colorless, odorless, and tasteless.
Smoke particles can preventing air filtering.

33. Contaminated and Toxic Smoke
Smoke damage may be the most expensive by-product of a fire.
Contamination with radioactive material or polychlorinated biphenyl (PCB)
Cost of a cleanup
Hanford, WA, nuclear power plant cleanup
Toxic effect of PCBs

34. Corrosion and Smoke Movement
Plastics containing halogens can form corrosive acids.
Fire gases rise due to buoyancy.

35. Summary Fire behavior is critical for all fighters
Compartment fires are complex and dynamic
Fire behavior is influenced by building construction
Fire fighters are at great risk from rapid fire growth
High flame spread materials
Several possible approaches to control the problem of fast fire growth

36. Summary
Smoke
used to describe the collective group of solid and liquid particulates and gases.
can affect occupants, fire fighters, and buildings in many ways.