PIN-TECH™ Bubble-Tight <500 ppm Pressure Relief Vent


Series 56000 Bubble-Tight <500 ppm Pressure Relief Vents are designed and tested to address concerns about the leakage of fugitive emissions prior to set point, and parts per million (ppm) emission rates.

Protectoseal’s PIN-TECH vents are mounted to the vapor space flange connection of a storage tank or vessel. The vents utilize a unique technology that employs a buckling pin to hold the vent piston closed (Fig. 1) with zero leakage up to the relief set point. The pin is an accurately machined, straight metal rod. It is configured to precisely sense transmitted axial forces that are generated as a result of tank pressure. The force required to buckle the pin is governed by Euler’s Law and is a function of the pin’s metallurgy, length and diameter. An exact buckling force can be determined for any specific pin configuration. When the pressure in the tank reaches the vent set point, the axial force is sufficient to buckle the pin and the vent sealing piston is allowed to move to its full open, relieving position (Fig. 2). The pin buckles completely and instantaneously.

Environmental Regulations: Protectoseal’s PIN-TECH vents provide a means of complying with the stringent VOC emission requirements mandated by the United States Environmental Protection Agency (EPA) outlined in Code of Federal Regulations (40 CFR).


  • Reduces fugitive emissions of VOC’s mandated by the U.S. Environmental Protection Agency (EPA)
  • Fast Inspection, easy maintenance – buckling pin can be quickly replaced
  • Sealing capabilities to less than 500 ppm
  • Accurate and repeatable set points
  • Reduced maintenance costs, far less than those of rupture disks
  • Sizes: 2” (DN 400) through 24” (DN 600)
  • Flange Connections: Mates with applicable ANSI, API or DIN PN 16 flange connections
  • Materials: Aluminum, Steel, Stainless Steel and Alloy C/C276
  • Standard Setting Range*: Pressure: 0.75 – 15 PSIG | 51.71 – 1034.21 mbar

*Settings vary by size

  • Flange Connections: Other drilling patterns available upon request
  • Diaphragm Materials: FEP, Viton®, Buna N, EPDM, Neoprene; other materials available upon request
  • Special Coatings: PROSHIELD™, FEP and Kynar®
  • Testing / Certification: Optional testing and certification for <500 ppm leakage
  • Instrumentation: Optional lift indicators, Explosion Proof Class 1: Groups A, B, C & D / NEMA Group 7 and 9, Mechanical indicator also available; optional testing and certification for less than 500 ppm


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