ASTM D635
Standard Test Method for Rate of Burning and/or Extent and Time of Burning of Plastics in a Horizontal Position
This test method was developed for polymeric materials used for parts in devices and appliances. The results are intended to serve as a preliminary indication of their acceptability with respect to flammability for a particular application. The final acceptance of the material is dependent upon its use in complete equipment that conforms with the standard applicable to such equipment.
The rate of burning and other burning phenomena will be affected by factors such as density, pigments, any anisotropy of the material, and the thickness of the specimen. Test data shall be compared only for specimens of similar thickness, whether comparisons are being made with the same or with different materials. The rate of burning and other burning phenomena will vary with thickness.
Burning tests require certain variables to be arbitrarily fixed, for example, specimen size, energy source and application time, and end points. Materials will be found that are unusually sensitive to one or more of the conditions chosen for this method, which can lead to highly variable results. Additional burning characterization by other methods is highly desirable in such cases.
In this procedure, the specimens are subjected to specific laboratory test conditions. If different test conditions are substituted or the end-use conditions are changed, it will not always be possible by or from this test to predict changes in the fire-test-response characteristics measured. Therefore, the results are valid only for the fire-test-exposure conditions described in this procedure.