An Example of the Use of Standard Flammability Criteria for Performance Analysis of Materials: Polycarbonate and PMMA

A detailed flammability evaluation of two different materials is presented, as an example of how important is physical observation and detailed analysis in the interpretation of test data. The objective is to provide different criteria that could allow the use of standard test data in fire modeling. The tests used are the lateral ignition and flame spread test (ASTME-1321) and the oxygen consumption calorimeter (ASTM-E-1354). The materials evaluated are a polycarbonate (Lexan) and compared to a commonly studied ideal material, PMMA (i.e., Poly-methyl-methacrylate). Lexan is a solid plastic sheet, generally considered as fire resistant. The solid plastic sheet is proposed as an alternate to PMMA for use as containment windows for glove boxes containing radioactive components in nuclear facilities. For idealized materials, such as PMMA, heat transfer from the flame to the fuel controls flame-spread rates. This study shows that the behavior of the Lexan, in the case of a fire, will be first governed by melting. Furthermore, if the material is placed vertical, the results indicate that the motion of the molten fuel, rather than the transport of energy will control flame-spread rates. Additional medium-scale tests fully confirms the main results obtained by the small-scale experiments.