Marshall Excelsior Co. (MEC) designed its mini quad-port relief valve manifold to allow for the service and exchange of tank vapor relief valves while tank systems are fully operational. The mini quad-port relief valve, which is distributed by Bergquist Inc., can be used in all large ASME tanks equipped with standard 2-inch FNPT vapor relief valve openings. According to Bergquist, the relief valve includes all of the same features of MEC’s flanged versions, but it costs less and does not require costly tank modifications. The valve uses high-flow 1 ¼-inch MNPT external relief valves. It is available in brass for LP gas service or aluminum for NH3 service. The manifolds and relief valves come with Viton or NBR seals for high performance in LP gas or NH3 uses. Additionally, the relief valve manifold has an extra relief valve excluded from the flow rating to allow for service or exchange of any relief valve without evacuating the tank.