Vacuum relief is automatic on vertically-installed vents and manual on horizontally-installed vents.
Six-inch (152-mm) flame arrester safely dissipates heat and prevents flashback from external ignition sources. Justrite Drum Vent for Petroleum Based Applications, Polyethylene, Vertical, Flame Arrester, 2" Bung, Brass/Polyethylene, 08005 | Justrite Drum Vent for Petroleum Based Applications, Polyethylene, Vertical, Flame Arrester, 2" Bung, Brass/Polyethylene, 08005 08211 includes a 9-in(229-mm) wide polyethylene funnel to facilitate solvent waste disposal and reduce spillage. The brass vent provides automatic pressure and vacuum relief, and includes a brass cap with safety chain tethered to the vent to prevent misplacement or loss.