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Temperature Uncertainties for Bare-Bead and Aspirated Thermocouple Measurements in Fire Environments



William M. Pitts, E Braun, Richard D. Peacock, Henri E. Mitler, Erik L. Johnsson, Paul A. Reneke, L G. Blevins


Temperature measurements have been made for natural-gas and heptane fires in a reduced-scale enclosure using a variety of bare-bead and aspirated thermocouples in order to characterize the uncertainties. The focus is the role of radiative heat transfer and the effects of finite time response on the measurements. The findings show that significant errors are possible for all thermocouples considered. Aspirated thermocouples reduce, but do not eliminate, such uncertainties. An alternate approach, use of several bare-bead thermocouples with extrapolation to zero diameter, is not easily implemented in the time-varying temperature environments characteristic of fires.
Proceedings Title
American Society for Testing and Materials (ASTM)
Conference Dates
December 3, 2001
Conference Title
Thermal Measurements: The Foundation of Fire Standards


fire research, fire science, fire suppression, aspirated thermocouples, enclosures, fire tests, measurement uncertainties, temperature measurements, thermocouples


Pitts, W. , Braun, E. , Peacock, R. , Mitler, H. , Johnsson, E. , Reneke, P. and Blevins, L. (2001), Temperature Uncertainties for Bare-Bead and Aspirated Thermocouple Measurements in Fire Environments, American Society for Testing and Materials (ASTM), -1, [online], (Accessed June 15, 2024)


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Created December 3, 2001, Updated February 19, 2017