Emergency vents are installed on aboveground storage tanks as a code requirement. Emergency vents provide high capacity pressure relief if the tank is exposed to fire. When the internal tank pressure reaches the opening pressure of the vent, the weighted cover moves up on the center pin allowing air to escape. When the internal tank pressure falls, the cover automatically lowers back onto the body and is automatically reset.
The 244 emergency vent is for "emergency pressure relief only" and must be used in conjunction with a "normal vent" or pressure vacuum vent. The 244 emergency vent must be properly sized and selected for each specific tank application in order to meet the proper "venting capacity" requirements.