United States Government Publishing Office publisher pbl distributor dst United States Commerce Department National Institute of Standards and Technology (NIST) author aut Government Organization Bryant, Rodney A. author aut text government publication eng GOVPUB Executive Agency Publications executive 2023-10-27 Commerce Department 2022-05-10 monographic deposited born digital 47 digital object pages C 13. https://www.govinfo.gov/app/details/GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7 P0b002ee1c1bb3f62 on1389890276 (OCoLC)1389890276 DGPO 2023-10-27 2026-06-27 GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7 machine generated eng fdlp C13 GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7 b5c8beb1a3518ddb4ec8e21659ce4bc7 GOVPUB NIST Technical Notes NOTE: THE “DATE ISSUED” ABOVE MAY DEFAULT TO JANUARY 1ST OF A GIVEN YEAR. TO THE VIEW THE MOST ACCURATE DATE OF ISSUE, REVIEW THE TITLE PAGE OF THE PUBLICATION. Studies or reports which are complete in themselves but restrictive in their treatment of a subject. Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject area. Often serve as a vehicle for final reports of work performed at NIST under the sponsorship of other government agencies. National Institute of Standards and Technology Commerce Department. National Institute of Standards and Technology. 2022 2022-05-10 https://www.govinfo.gov/app/details/GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7 https://www.govinfo.gov/content/pkg/GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7/pdf/GOVPUB-C13-b5c8beb1a3518ddb4ec8e21659ce4bc7.pdf Exhaust Flow Calibration Using Tracer Gas Dilution Constant-injection Duct flows Fires Flow meters Flow meters--Calibration Flow mixing Heat release Oxygen consumption calorimetry Photoacoustic gas detection Tracer gas dilution Bryant, Rodney A. creator Bryant, Rodney A. National Institute of Standards and Technology (U.S.) Engineering Laboratory mdu U.S. Dept. of Commerce, National Institute of Standards and Technology 2022-05-10. monographic 1 online resource (47 pages) : illustrations (color) text technical report eng Exhaust flow measurements have been found to be a significant source of uncertainty for measurements of heat release rate in large-scale fire experiments. Asymmetric or skewed velocity distributions are often present in the exhaust ducts for open calorimetry systems used in large-fire research facilities, therefore making it difficult to measure exhaust flow accurately. Tracer gas dilution is a standard test method for determining volume flow in ducts. It is not sensitive to flow distribution and is derived from measurements independent of most flow monitoring techniques. Therefore, it is well suited for in-line calibrations of flow measurement devices in the exhaust ducts of facilities conducting large-scale fire experiments. For the first time, the method has been applied to calibrate the routine exhaust flow measurements at the National Fire Research Laboratory as a means to reduce the measurement uncertainty associated with open calorimetry systems. Measurement uncertainty for the calibration is estimated at 3 % and accounts for potential error due to incomplete mixing of the tracer. Multi-port sampling of the tracer, which is not part of the existing standard test method, is also demonstrated as a means to reduce the potential for measurement error due to incomplete mixing. Exhaust velocity and mass flow are necessary to compute heat release rate, and both are determined by averaging pitot probes installed in the exhaust ducts. An in-line calibration of the averaging pitot probes was conducted using tracer gas dilution. Measurement uncertainty for calibrated exhaust velocity and calibrated mass flow is estimated at 3 %. The in-line calibration of the exhaust flow measurement is an improvement over the accepted practice of comparing oxygen consumption calorimetry with heat release rate measured at a gas burner to develop a correction for the flow measurement. It is valid for a wide range of flow conditions and decouples measurement error between oxygen consumption calorimetry and fuel consumption calorimetry; therefore improving overall measurement accuracy for heat release rate. Rodney A. Bryant. May 2022. Title from PDF title page (viewed January 4, 2023). Includes bibliographical references. Approved by the NIST Editorial Review Board on 2022-04-26 Mode of access: World Wide Web. Systems requirements: Adobe Acrobat PDF reader. Flow meters Flow meters--Calibration Fires Tracer gas dilution Heat release Oxygen consumption calorimetry Constant-injection Photoacoustic gas detection Flow mixing Duct flows https://doi.org/10.6028/NIST.TN.2220 The exhaust flow calibration using tracer gas dilution exhaust flow calibration using tracer gas dilution