Some updates have been made to ASTM D6413 Standard Test Method for Flame Resistance of Textiles (Vertical Test) commonly used in flame resistant apparel testing.
The most significant changes are based around the char length measurement:
- The basis weight defined by the standard as “the weight of cloth before the addition of any fire retardant treatment or coating” was removed, and ASTM D3776 Test Methods for Mass per Unit Area (Weight) of Fabric was added. It was determined that “basis weight” was a source of variability in laboratories, and the consensus of the D13.52 subcommittee was that all materials (inherent, treated, and coated) should be weighed in-house before testing. The weight of the as-received fabric will now be used to determine the tearing force for char length.
- Previously, the weight used as the tearing force to determine char length was listed in two units (grams and ounces); however, due to a soft conversion, they were not exact equals. As a result, some laboratories were using the weights listed in grams, and others used the weight listed in ounces. The subcommittee reached consensus that this was another source of variability the weights listed in ounces were moved to the appendix. Testing completed to the 2015 edition should be performed using the metric weights (grams).
Never accept only ASTM D6413 data for any clothing. There is NO standard which uses pass/fail criteria using ASTM D6413 alone. These garments are falsely labeled as FR. Flame resistant garments must meet a battery of tests for arc flash, flash fire, fire fighter protector etc. Never accept ASTM D6413 labeled garments as truly flame resistant