Rationale

The microscale combustion calorimeter signal exhibits thermal drift of 5-7 W/g over the test duration and random temporal fluctuations of 1 W/g during the test when no test specimen is present during normal operation of the instrument (18). The combined effect is called baseline drift and noise and it varies from test to test so it must be corrected in situ. Baseline drift can cause significant error in the measurement of flammability characteristics if the combustion signal of the sample is of comparable magnitude to the drift. The detection limit of the instrument is 3 W/g (18) when the calorimeter signal is corrected for baseline drift so the limit of quantification (LOQ) is 10 x 3 W/g = 30 W/g. This ballot provides a method to correct the calorimeter signal for baseline drift when the maximum deflection of the calorimeter signal during sample combustion is less than the LOQ of 30 W/g. The baseline correction method is described in a new Appendix X3 to the standard and supporting references have been added. This ballot adds this caveat to Limitations in section 6 and clarifies Calibration in section 8. Requirements for when Appendix X3 apply are given in Section 12. This work item is a collaboration between the US Federal Aviation Administration who developed the test method and generated the research findings that led to this work item, and two users of this method who routinely test low heat release materials, Boeing and the University of Dayton Research Institute. Due to limited travel dollars (or inability to travel), the authors will not be able to attend D20.30 meetings in person to address negative items associated with this work item, but the authors are willing to support virtual meetings to discuss negative items and find solutions to address those negatives. As a result of the inability to travel, any negative received on this ballot item may be adjudicated electronically in a subsequent ballot using the normal balloting process (see Regulations Governing ASTM Technical Committees, a.k.a. “Green” book, section 11.4 for Subcommittee balloting and section 12.4 for Main/Concurrent balloting). Therefore, if you plan on submitting a negative, it is important to submit a complete statement identifying the applicable section(s) of the ballot item, the reason(s) for your negative vote, and if possible, alternate wording to satisfy your negative. Prior to any electronic adjudication, the specific D20.30 subcommittee section responsible for the ballot item (D20.30.03) will attempt to resolve the negative with the interested parties. For ease of review, only the sections being updated are shown below in red color underlined text. Other than these changes, there were no changes made to this standard. If you have any questions or concerns about these changes please contact me and I’ll be glad to answer your questions and discuss your concerns. Thank you for your consideration and potential affirmative vote on this standard revision.