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Radiative Heat Flux Measurement Uncertainty



Rodney A. Bryant, C A. Womeldorf, Erik L. Johnsson, Thomas J. Ohlemiller


As part of an effort to characterize the uncertainties associated with heat flux measurements in a fire environment, an uncertainty analysis example was performed using measurement data from a room corner surface products test that followed the guidelines of ISO 9705. Equations to model the heat transfer at the surface of a Schmidt-Boelter (thermopile) type total heat flux gauge were selected for use to calculate the incident radiative flux from a total heat flux measurement. The effects of the heat flux measurement uncertainty sources were evaluated by conducting an uncertainty propagation on the resulting equation for incident radiation. For the model equations and the example conditions selected, the free-stream temperature estimate and the heat flux gauge calibration constant were suggested as major uncertainty contributors. The study demonstrates how to systematically identify major sources of uncertainty for the purpose of reducing total uncertainty and therefore enhancing experiment design.
Fire and Materials
No. 5


heat flux, heat flux gauge, heat flux measurement, radiative flux, room corner, standard fire test, uncertainty


Bryant, R. , Womeldorf, C. , Johnsson, E. and Ohlemiller, T. (2003), Radiative Heat Flux Measurement Uncertainty, Fire and Materials, [online], (Accessed May 19, 2024)


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Created October 1, 2003, Updated June 2, 2021