Fire Modeling
PDI uses Fire Dynamics Simulator (FDS) and Consolidated Fire and Smoke Transport (CFAST) published by the National Institute of Standards and Technology (NIST) to model fire growth and heat production rates in compartments and complex building environments. PDI may also use fire modeling to assess independent events such as sprinkler activation and egress times. In many cases, fire growth models can be used to represent specific fire and other compartment conditions, as well as the effects on egress such as incapacitating exits and creation of untenable environments due to smoke and toxic gas production. PDI uses nationally-published data regarding the ignition properties, flame spread, and smoke generation of various materials for the most accurate prediction results.
Smoke Modeling
PDI uses the latest in fire growth and smoke movement modeling software to predict a building’s response to hypothetical fires. These models are run under varying building geometry and ventilation conditions to determine which set of parameters best predicts what would occur. Our experience in fire testing and research allows PDI to draw upon national databases of fire test data to develop a specific solution to a particular problem.
Egress Modeling
Occupant egress from a building or space can be evaluated using techniques described in the National Fire Protection Association (NFPA) and Society of Fire Protection Engineers (SFPE) handbooks.
These handbooks give PDI’s engineers data on occupant reaction times, travel speeds, and discharge times through doors. This type of analysis will allow PDI to calculate egress times under normal or adverse building conditions including during power outages or when several doors, corridors, stairs, or egress paths are incapacitated. PDI will provide egress analysis to reflect delayed occupant notification representing an impaired fire alarm system or incapacitated occupants.
Once the timelines are established, they can be compared with fire modeling results to answer questions such as:
- Is the egress time less than the time to reach untenable conditions?
- Is installing sprinklers in my building/space necessary to allow occupants to egress safely?
- Do manual firefighting operations begin before internal wall temperatures imply a breach in fire resistance rated wall containment?