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Comparison of Flow Measurement Devices for Large Fire Experiments



Giovanni Di Cristina Torres, Rodney Bryant


Bi-directional probes are utilized throughout fire research and testing to measure fire induced flows due to their ability to measure flow which changes direction, and to withstand hostile environments. However, they are not available commercially and researchers must acquire them through custom fabrication. S-type probes (S-probes) work on the same principle as bi-directional probes thereby offering the same benefits. However, S-probes also feature reliable manufacturing and calibration standards. For the first time the performance of bi-directional and S-probes are compared in side-by-side experiments. Measurements of a steady flow in a well-characterized wind tunnel were examined and the probes were used to measure the velocity profile across a turbulent jet from a blower fan. In both scenarios, the S-probe performed comparable to or better than the bi-directional probe in terms of accuracy. The results demonstrate the S-probe as a suitable alternative to the bi-directional probe for measurements of fire-induced flow.
Technical Note (NIST TN) - 2285
Report Number


Fire-Induced Flow, Flow Calibration, Flow Speed Measurement, Pitot Probe


Di Cristina Torres, G. and Bryant, R. (2024), Comparison of Flow Measurement Devices for Large Fire Experiments, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed May 26, 2024)


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Created April 12, 2024