A milligram‐scale flame calorimeter pyrolyzer system used to emulate burning of nonthermally thin solid samples

Abstract

SummaryA new Milligram‐scale Flame Calorimetry (MFC) pyrolyzer system was developed to approximate heating conditions experienced by material samples in gram‐scale tests, such as cone calorimetry. The main features of this pyrolyzer system are a miniature flat heating coil embedded into a platform supporting the sample crucible. The use of a constant power rather than a constant heating rate operation mode distinguished the new MFC from the other mg‐scale flammability test method—microscale combustion calorimetry (MCC). A series of tests was carried out using the new MFC, cone, and MCC on five synthetic polymers representing a wide range of flammability behavior. All methods produced similar solid residue yields. The MFC peak heat release rate (HRR) was found to correlate linearly with the cone peak HRR (R2 = 0.93). The MCC peak HRR did not exhibit a strong correlation with the corresponding cone data. The new MFC was found to produce heat of combustion (HOC) values nearly identical to those measured in cone calorimetry. The MCC had a tendency to produce higher heats of combustion. Both MFC and MCC measured sample ignition temperatures that showed some correlation with the square root of the time to ignition measured in a cone calorimeter. The MFC airborne particular yield was found to correlate well (linear R2 = 0.91) with the average specific extinction area measured in the cone tests. It was concluded that the newly designed MFC can deliver relatively accurate flammability measurements similar to cone calorimetry while using three orders of magnitude smaller samples.