Features Self-actuated operation. Relieves excess air or gas pressure. Relieves excess liquid pressure in the absence of air or gas blanketing. Designed to prevent vacuum formation that could cause the vessel to buckle. Body and all internal parts designed to operate after exposure to process fluids and withstand direct flushing and cleansing of sterilizing agents, caustics, water or steam. Allows complete drainage after operation and/or flushing and minimizes crevices which might trap contaminants or promote freezing in cold environments. Standard FKM O-ring seats on both discs provide tight shutoff. All materials are corrosion resistant and all exposed surface finishes are controlled to enhance sanitary features. Tamper-proof lead sealed cap. Manufactured to ASME Code Section VIII and Section XIII requirements. Capacities on compressible fluid certified by the National Board of Boiler and Pressure Vessel Inspectors.