Reading the Fire: Building Factors

First of the critical building features is construction method. Building construction influences both fire behavior and structural stability under fire conditions. Combustible construction such as wood-frame, ordinary (masonry and wood), and heavy...

Fire Behavior Preplanning

Examining buildings and predicting potential fire behavior can be approached with varying degrees of formality. At the simplest level, firefighters should examine their surroundings on an ongoing basis. Look at buildings you visit for other purposes and develop the habit of identifying critical building features that will impact fire development. Think about how hot smoke and flames will move through the structure and how the fire will develop. On a more formalized basis, individuals (or even better) fire companies can develop fire behavior pre-plans as part of their study of fire behavior. This practice can and should also be integrated into development of target hazard pre-plans.

The first step in the fire behavior preplanning process is to gather information about the building. This will generally include the address, general description, construction type, occupancy, type of contents, building configuration (including extent of compartmentation), ventilation profile, and fire protection systems. Draw a simple floor plan and (if possible) take photos to help communicate your fire behavior preplan to others.

Basic information about the building and its contents provides a basis to predict anticipated fire development. Think about how fires would develop given different points of origin. Visualize fire development and the spread of heat and smoke inside the building. What are the likely avenues of fire travel? How might the ventilation profile change (is failure of window glazing likely?). Don't limit yourself to just one scenario; consider a variety of alternatives to build a more comprehensive picture.

Calculate the required fire flow (more on this in the next article). How might this influence your tactical operations?

Study and Discussion Questions

Use the information presented in this article to answer the following questions:

  1. What are the five categories of fire behavior indicators?
  2. What are the major building factors that impact on fire behavior?
  3. How do void spaces influence fire development and spread?
  4. How do efforts to increase energy efficiency impact fire development?
  5. Given that hot gases rise, how is it that carpet and carpet padding can be a significant contributor to fuel load?
  6. What is the difference between heat of combustion and heat release rate?
  7. What fuel characteristics influence heat release rate?
  8. What size related factors should you consider when thinking about fire development in a building?
  9. How does fire development differ when a compartment has a high ceiling?
  10. Briefly describe what is meant by the term "ventilation profile".
  11. How does the ventilation profile influence fire development?
  12. How do fire suppression systems such as automatic sprinklers impact fire development?

Fire Behavior Preplan Activity

Develop a fire behavior preplan for a building in your response area and share the information with other members of your department. Use the preplan to facilitate a discussion of how the building factors presented in this article apply to this specific building and occupancy.

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