Zook ProPOS Rupture Disc – Low Pressure

The Zook ProPOS Rupture Disc is a bi-directional rupture disc designed to prevent over-pressurization and provide vacuum protection for processing and storage tanks. The assembly design allows ultra low-pressure relief in the positive direction (starting at 1″ of water column differential). The assembly may be specified to protect equipment in the vacuum direction (up to full vacuum).

  • Temperature ratings to 500°F (260°C)
  • Vacuum Relief ratings from 1″ WC to 30″ WC


  • Burst indication
  • Laser Cut Pressure Cap* Provides protection to seal in case of negative (vacuum) pressure
  • Laser Cut Burst Cap* Provides negative (vacuum) pressure relief at specified rating
    *This option will significantly reduce the flowing capacities in the Positive pressure relief direction.

How the Zook ProPOS Rupture Disc:

Positive Pressure Relief – Controlled by the Girdle.
As the pressure in the system approaches the positive burst setting, the seal presses against the girdle, deflecting it towards the knife blades built into the outlet holder. As the girdle passes the knife blades, the seal is cut relieving the POSITIVE pressure. The laser cut holes in the Burst Cap or Pressure Cap provides optimum flow when the rupture disc relieves in the positive pressure direction.

Vacuum Relief – Controlled by Metal Top Section.

The Burst Cap, under tension loading, relieves negative (vacuum) pressure when a vacuum occurs in the system.

ProPOS Components:

  • Girdle – Standard material is 316SS. Also available in PTFE. The girdle controls the standard min. to max. inches of water column positive pressure rating
  • Seal – Evenly distributes pressure in both the positive and vacuum pressure direction
  • Protective Ring – Provides seat area protection for seal on applications that do not require negative (vacuum) pressure relief

The Zook ProPOS Rupture also uses the  DiscProPOS Disc Holder that has been specifically designed for it.

  • Insert type Rupture Disc Holder – designed exclusively to be used with the ProPOS Rupture Disc


  • Highly accurate, ultra-low burst pressures available
  • Dual-Acting, tension-loaded design, with laser cut metal top section and girdle (when ordered in 316SS)
  • Sizes 39 thru 129
  • 316SS girdle is standard. Other materials available
  • Flat seat design
  • Burst ratings from 19 of water column to 150 psig
  • Temperature ratings to 500°F (260°C)
  • 3-dimensional stainless steel tag is standard
  • Vacuum Relief ratings from 1″ WC to 30″ WC
  • Positive Pressure relief from 2 psig to 150 psig


  • Insert type Rupture Disc Holder – designed exclusively to be used with the ProPOS Rupture Disc
  • Non-torque sensitive flat seal design
  • The ProPOS Holder and Rupture Disc are assembled using safety designed side clips
  • Standard materials of construction: 316SS and carbon steel. Other materials available upon request
  • Permanently attached stainless steel nameplates are standard. Nameplates indicate flow direction and provide visual verification that holder assembly is properly oriented in the piping system

Contact our Process Equipment Team:

Noel Bracken – Tel: 083 0891204

Conor Foley- Tel: 021 461 7206