Masking the flame absolutely, which smothers the flame since the combustion each takes advantage of the readily available oxidizer (the oxygen in the air) and displaces it from the region throughout the flame with CO2; Smoke leakage (S): The duct shall not have a leakage exceeding 5 m³/h for each https://ductworth-installation78990.blogspothub.com/35600305/not-known-facts-about-fire-resistant-ductworth-isntallers