Uncertainties in measuring heat and smoke release rates in the room or corner test and the SBI test (NT TR 477)

Abstract

  When performing fire testing and classifying materials, Heat Release Rate (HRR) and Smoke Production Rate (SPR) are two of the most important quantities to determine. The calculation of HRR and SPR, however, involves several measurements and approximated constants. These all suffer from error, which may also depend on the experimental set-up. To give the total error of the HRR and the SPR, respectively, the individual contributions must be derived. In this work, the individual sources of errors are defined for the HRR and the SPR calculations, with regard to the Room/Corner Test and the Single Burning Item (the SBI) test. From the individual errors the combined expanded uncertainty has been calculated, using a coverage factor of 2, which gives a confidence level of approximately 95 %. For HRR measurements the uncertainty is presented for two different levels in the two different set-ups, i.e. 150 kW and 1 MW for the Room/Corner Test and 35 and 50 kW for the SBI. For the SPR the uncertainty is presented at 6 different levels for both tests ranging from 0.5 m2/s to 10 m2/s. In addition, guidelines are given for estimating the individual errors and calculating the combined expanded uncertainty for HRR and SPR measurements in general.