Rationale

The existing 9.1.2 currently requires "9.1.2 … all progressive flaming as previously recorded shall be included at the time of occurrence. A straight line shall be used to connect successive points." As currently written, 9.1.2 appears to be clear that all progressive flaming is to be included in the FSI calculation. Further clarification to the standard is required to ensure that there is no confusion about the fact that ASTM E84-26 is a 10 minute test which requires “all progressive flaming” to be included in both the FSI and SDI calculation, and, as stated in 9.2, the SDI is a comparison between the area under the curve developed by the test specimen versus the area obtained during the smoke calibration. Unless the smoke developed area reverts to zero, this is required to be included in the SDI calculation over the full 10 minute duration of the test.