External “Pop-Action” Supplementary Pressure Relief Valves for Small ASME Containers and DOT Cylinders 3127 and 3129 Series


Designed for use as a supplementary relief valve on small ASME above ground and underground containers. They may also be used as a primary or secondary relief device on DOT cylinders, or as hydrostatic relief valves.

All working components of these relief valves are outside the container connection, so the valves must be protected from physical damage.


  • “Pop-action” design keeps product loss at a minimum.
  • Relief valve designed to automatically reseat firmly after discharge.
  • Resilient seat disc provides a “bubble-tight” seal.


Body Brass
Spring Stainless Steel
Seat Disc Resilient Rubber