Emergency Pressure Relief Manhole Cover Vent


Protectoseal Series 53300 Emergency Pressure Relief Manhole Cover Vent provides emergency pressure relief for storage tanks as well as convenient access for tank cleaning, inspection and repair work. Unit is designed for installation on the manhole openings of tanks and provide a means of relieving large volumes of vapors, beyond the capacity of a normal operating vent, if an emergency fire involvement of the tank should occur; the vent opens fully to allow escape of vapors and prevent damage to the tank due to excessive pressure. The cover must be manually repositioned after venting has occurred.


  • 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
  • Copper bonding wire prevents loss of cover
  • Four point guiding of pallet assembly is provided by web assembly to insure proper location of pallet on seat and smooth lift under pressure conditions
  • Unit and associated weights serialized for ease in identification
  • Flow at fully open pressure marked on unit [OSHA 1910.106(b)(3)(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: 1.10 – 6 oz/in2 | 4.74 – 25.86 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®
  • Cover retention brackets available
  • Material certifications for flange and seat


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