... fire-resistant and anti-static,andit is suitable for conveying materials under coal mine wells. (HG 2539)Tech ... with ethand blowtorch Flame combustion Average duration of flame for four test samples , s , ≤ 30 3 ... Duration of flame for any individunl test sample , s , ≤45 10 ... Flameless combustion Average duration of flame for four test samples , s , ≤ 120 - Duration of ...