CFAST
Definition
Consolidated Fire and Smoke Transport model from NIST; a multi-room two-zone fire model used for evacuation time analysis, detector performance prediction, and smoke transport reconstruction in multi-compartment buildings.
- Full form
- Consolidated Fire and Smoke Transport
- Developer
- NIST
- Model type
- Two-zone, multi-room
- Uses
- Evacuation timing, detector activation, smoke transport
- Contrast model
- CFD models like NIST's Fire Dynamics Simulator (FDS)
Common questions
How does CFAST's two-zone approach differ from a full CFD fire model?+
CFAST divides each room into just an upper hot layer and a lower cool layer and solves simplified equations for each, which runs far faster than a computational fluid dynamics model like FDS that resolves fine-grained temperature and flow fields, at the cost of less spatial detail.
Why would a fire investigator choose CFAST over a full CFD simulation?+
For multi-room or multi-storey reconstructions where the question is overall smoke spread and timing rather than fine flame-front detail, CFAST's speed lets an analyst test many scenarios quickly, reserving CFD modelling for cases needing finer resolution.
Related terms
- Alpert Correlation
- An expression derived by Ronald Alpert at FM Global for ceiling jet temperature and velocity as functions of heat release rate, ceiling...
- Fractional Effective Dose (FED)
- A physiological model that combines exposure to CO, HCN, CO2, reduced O2, and heat into a cumulative incapacitation estimate. Used with FDS...
- Heskestad Correlation
- An analytical expression derived by Gunnar Heskestad at FM Global relating fire plume centreline temperature to heat release rate and height above...
- McCaffrey Plume Model
- A three-zone empirical model for fire plume centreline temperature and velocity developed by Brian McCaffrey at NIST, with separate power-law relationships for...
- NIST FDS (Fire Dynamics Simulator)
- A freely available large-eddy simulation CFD code from NIST that models coupled fire, smoke, and heat transfer in three-dimensional geometries. Validated against...
- Soot Horizon
- The visible line on vertical surfaces marking the lowest height reached by the smoke layer during the early fire growth phase, representing...
- T-Squared Fire Growth
- A model in which heat release rate increases as the square of time from established burning (HRR = alpha × t²). The...
- Two-Zone Model
- A compartment fire model that divides the room into an upper hot gas zone and a lower cool ambient zone, computing their...
- Virtual Origin
- In plume correlation models, the effective point source location below the actual fuel surface from which the plume behaves as if it...