Heskestad Correlation
Definition
An analytical expression derived by Gunnar Heskestad at FM Global relating fire plume centreline temperature to heat release rate and height above the virtual origin. Widely used in fire engineering and forensic reconstruction.
- Author
- Gunnar Heskestad
- Affiliation
- FM Global
- Relates
- Plume centreline temperature to heat release rate and height
- Field
- Fire engineering and forensic fire reconstruction
Common questions
What is the correlation used for in a forensic fire investigation?+
Investigators use it to work backward from observed damage, such as char height or witness-reported flame extension, toward an estimated heat release rate for the fire, which supports reconstructing fuel load and fire growth in the absence of direct instrumentation.
Does the Heskestad correlation apply equally to any compartment fire?+
It was derived for an open, unconfined fire plume above a defined virtual origin. Applying it inside a compartment requires accounting for ceiling effects, ventilation, and confinement, so engineers adjust or validate it rather than using the open-plume form directly.
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...
- CFAST
- Consolidated Fire and Smoke Transport model from NIST; a multi-room two-zone fire model used for evacuation time analysis, detector performance prediction, and...
- 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...
- 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...