The NIST 3 Megawatt Quantitative Heat Release Rate Facility - Description and Procedures

Published

September 1, 2004

Author(s)

Rodney A. Bryant, Thomas J. Ohlemiller, Erik L. Johnsson, Anthony P. Hamins, B S. Grove, William F. Guthrie, Alexander Maranghides, George W. Mulholland

Abstract

The 3 Megawatt Heat Release Rate Facility was developed at NIST as a first step toward having broad capabilities for making quantitative large scale fire measurements. Such capabilities will be used at NIST to validate fire models and to develop sub-grid models. It will also serve to provide a data base for studying a broader range of fire phenomena, and to address issues related to material acceptance and fire codes. An equally important objective is to provide templates for use by other laboratories including commercial testing facilities to improve the quality of their data. The facility is capable of measuring heat release rates in the range of 0.10 to 3.0 MW including brief peaks as high as 5 MW. The expanded uncertainty (95 % confidence interval) is 11 % of the heat release rate for fire sizes larger than 400 kW. The response time of the system is such that it can accurately resolve dynamic heat release rate events of 15 seconds or more. Key features of the design and fabrication of these systems are presented including detailed schematics and the rationale for the choices made. Transient response and gas dispersion in the sampling system, sampling from a non-uniform duct flow, and making accurate total flow measurements using bi-directional probes are dealt with in the design. The design of a natural gas burner for measurement confirmation, including the special flow control and flow metering capabilities, is presented. The general design of the software allowing the display of nearly real-time heat release rates with corrections for sampling/instrumental delay and response times is also described.

Citation

NIST Interagency/Internal Report (NISTIR) - 7052

Report Number

7052

NIST Pub Series

NIST Interagency/Internal Report (NISTIR)

Pub Type

NIST Pubs

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DOI Link

Keywords

calibration burner, fire measurement, fire testing, heat release rate, measurement uncertainty, oxygen consumption calorimetry, peak heat release rate, response time

Citation

Bryant, R. , Ohlemiller, T. , Johnsson, E. , Hamins, A. , Grove, B. , Guthrie, W. , Maranghides, A. and Mulholland, G. (2004), The NIST 3 Megawatt Quantitative Heat Release Rate Facility - Description and Procedures, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.7052 (Accessed October 8, 2025)