Emergency Pressure and Vacuum Relief Vent


Emergency Pressure and Vacuum Relief Vents provide emergency relief when installed on the manhole opening of a storage tank. In emergency situations (external fire involvement of the tank), normal venting devices may be too small to prevent over-pressurization of the tank. The device provides the necessary pressure relief capacity to maintain the tank in a safe operating range. Spring-loaded vacuum pallet assembly allows flow of make-up air into tank’s vapor space to relieve negative pressure.


  • Certified test report verifying specified settings and leakage performance
  • “Air-cushion” pallet design for low leakage performance of no more than 1 SCFH at 90% of the set pressure
  • Peripheral pallet assembly guides and center pallet stem guide ensure proper alignment of pressure pallet assembly on the seat and smooth lifting and reseating action
  • Serialized unit and associated weights for easy identification and traceability
  • Flow at fully open pressure marked on unit [OSHA 1910.106(b)(2)(v)]
  • Sizes: 16” (DN 400) through 24” (DN 600)
  • Flange Connections: Mates with applicable ANSI, API flange or DIN 16 PN connections
  • Materials: Aluminum, Steel and Stainless Steel
  • Testing & Certifications: Conforms with the latest ATEX Directive
  • Standard Setting Range*: Pressure: 0.75 – 6 oz/in2 | 3.23 – 25.86 mbar
  • Standard Setting Range*: Vacuum: 0.5 – 0.75 oz/in2 | 2.15 – 3.23 mbar

*Settings vary by size

  • Flange Connections: Other drilling patterns available upon request
  • Diaphragm Materials: FEP, Viton®, Buna N, EPDM, and Neoprene; other materials available upon request
  • *Settings: Non-standard setting available
  • Special Coatings: PROSHIELD™, FEP and Kynar®
  • Instrumentation: Mechanical or electronic lift indicator
  • Material certifications for flange and seat
  • PURE-TECH™ Design – Special cleaning and packaging for the storage of ultrapure liquids


Viton® is a Registered Trademark of E. I. DuPont de Nemours & Co., Inc.
Kynar® is a Registered Trademark of Arkema, Inc.