Morrison Tank Emergency Vents

The Morrison 244 Series Emergency Vent is designed for use on aboveground storage tanks, as a code requirement that helps prevent tanks from becoming over-pressurized or ruptured if exposed to fire. The emergency vent series must be installed on shop fabricated atmospheric tanks built and tested in accordance to industry standards UL142, NFPA 30 & 30A and API 650. The emergency vent is not a substitute for a standard vent. A standard vent must also be installed on the tank to allow the tank to breath during normal operation. Tank-Emergency-Vents-1.jpg

Tank emergency vents must be sized to each tank application to meet “venting capacity” requirements. The Morrison 244 emergency vent consists of a body and a black powder coated cover (2" not powder coated) that moves up and down on a center pin. Pressure inside the tank forces the cover to lift up off the vent seat, allowing air to exhaust. The center pin guides the movement. When pressure falls the cover lowers back down onto seat and the vent is automatically reset.

When properly sized for the tank, this vent will conform to the requirements of NFPA 30, 30A, UL 142, UL 2244, ULC S601, API 2000, and PEI RP200.



2”, 3”, 4”, 5”. 6”, 8”, 10”

Venting Capacity

131,700 to 881,670 CFH

Mounting Connection

Male N.P.T, Female N.P.T., BSP, Flanged

Pressure Settings

8 or 16 oz/in2.


Cast Iron Powder Coated, Brass, Hard Coated Aluminum

Seat Material

Viton A or Viton B

Body Material

Aluminum, Brass or Iron


Mesh Stainless Steel