KB Duct Backdraft Damper helps installers meet 2015 NFPA requirements regarding installation of Explosion Isolation Device on all suction side ducts that transport material with KST value above zero. Constructed from heavy-duty welded steel, KB-NRV no-return explosion isolation valve protects workers and facilities from damaging effects of baghouse or filter explosion. Features include flanged inlet and outlet with coflanges, inspection access door, grounding lug, and locking mechanism.