Comparison of Algorithms to Calculate Plume Centerline Temperature and Ceiling Jet Temperature With Experiments.

Published

January 1, 2000

Author(s)

William D. Davis

Abstract

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.

Citation

NIST Interagency/Internal Report (NISTIR) - 6448

Report Number

6448

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

Download Paper

https://doi.org/10.6028/NIST.IR.6448

Keywords

ceiling height, predictive models, ceiling jets, experiments, fire models, fire plumes, zone models

Citation

Davis, W. (2000), Comparison of Algorithms to Calculate Plume Centerline Temperature and Ceiling Jet Temperature With Experiments., NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.6448 (Accessed October 11, 2025)