Z-Flex Z-Vent 3" Fire Stop Support Stainless Steel Venting (2SVSFSSF03) 3" Fire Stop Support Stainless Steel Venting Required when running Z-Vent stainless steel venting vertically through a floor Rated AL29-4C and is approved for Category I (vertical only), II, III & IV applications Designed for use where cool flue gases are vented under pressure