Comparison of Algorithms to Calculate Plume Centerline Temperature and Ceiling Jet Temperature With Experiments.
Comparison of Algorithms to Calculate Plume Centerline
Temperature and Ceiling Jet Temperature With
Davis, W. D.
NISTIR 6448; 35 p. January 2000.
Journal of Fire Protection Engineering, Vol. 12, No. 1,
Available from: National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
1-800-553-6847 or 703-605-6000;
Order number: PB2000-101595
ceiling height; predictive models; ceiling jets;
experiments; fire models; fire plumes; zone models
The predictive capability of two algorithms designed to
calculate plume centerline temperature (Evans) and
maximum ceiling jet temperature (Davis et. al.) in the
presence of a hot upper layer are compared with
measurements from a series of experiments. In addition,
comparisons are made using the ceiling jet algorithm in
CFAST (version 3.1), the unconfined plume algorithm of
Heskestad, and the unconfined ceiling jet algorithm of
Alpert. The experiments included ceiling heights of
0.58 m to 22 m and heat release rates (HRR) of 0.62 kW
to 33 MW. It was shown that the unconfined ceiling
algorithms underpredicted the temperatures while the
ceiling jet algorithm in CFAST overpredicted the
temperature in the presence of a hot layer. With the
combined uncertainty of the measurement and the
calculation roughly equal to +20%, the algorithms of
both Evans and Davis et. al. consistently provided
predictions either close to or within this uncertainty
interval for all fire sizes and ceiling heights.