Fire Protection Hazard Analysis

Fire Protection Hazard Analysis
for the Fire Protection Engineering PE Exam

Fire Protection Hazard Analysis
Fire Protection Hazard Analysis questions on the Fire Protection Engineering PE Exam will focus on:

  • Building Systems (electrical, mechanical)
  • Construction Materials
  • Room Dimensions and Arrangement in the Building
  • Building Contents (flammable liquids, high-piled storage)
  • Sources of Combustion Air
  • Position and Location of Doors
  • Characteristics of Occupants (numbers and locations)

From Fire Hazard Analysis Techniques
The goal of a fire hazards analysis is to determine the expected outcome of a specific set of conditions called a fire scenario. The fire scenario includes details – such as those listed above – that have an effect on the outcome of interest.
Fire Protection Hazard Analysis

  1. Select a target outcome. Some examples are:
    • avoid or limit occupant fatalities in the building
    • minimize the potential for the occurrence of fire
    • no release of hazardous material to threaten health, safety, or the environment
    • no undue hazards to the public from fire
    • building safety systems are not damaged by fire
    • property damage does not exceed acceptable levels
  2. Determine the scenario of concern by using:
    • records of past fires, either for the specific building or for similar buildings or class of occupancy
    • statistical data from NFPA or from the National Fire Incident Reporting System (NFIRS) on ignition sources, first items ignited, rooms of origin, etc.
  3. Select an appropriate method for prediction of growth rates:
    • Develop the Design Fire Curve – represents the heat release rate over time for the fire in question:
      • The design fire curve can be divided into four phases:
        1. ignition
        2. growth
        3. steady-burning
        4. decay
    • Predict the Fire Effects:
      • a realistic prediction of detector and sprinkler activation
      • time to start of evacuation
      • time to initial exposure of occupants
    • Fire Hazard Calculations:
      • Radiant Heat Flux – a measure of the rate of radiative heat transfer per unit area
      • Smoke Production
      • Fire Plumes and Ceiling Jet Temperatures and Velocities
      • Species Production – toxic or corrosive products of combustion:
        • carbon dioxide (CO2)
        • water vapor (H2O)
        • carbon monoxide (CO)
      • Depth of Upper Layer – estimate of the smoke layer velocity of descent
      • Toxicity – toxic gases produced by a fire
    • Computer Models
  4. Calculate the required time for occupants to move to a safe location:
  5. Analyze the impact of exposure of occupants or property to the effects of the fire:
  6. Examine the uncertainty in the Fire Protection Hazard Analysis:
    • Uncertainty analysis refers to dealing with the unknowns and variations:
      • assumptions in the models and the accurate representation of the input data
      • variability of any population of real people
    • the intent is to select design fires that provide a worst likely scenario
  7. Document the Fire Protection Hazard Analysis process:
    • include a discussion of uncertainty addressing the accurate representation of the data used and the sensitivity of the results to data and assumptions made

Fire Protection Hazard Analysis

NCEES

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