G36 Pressure Relief Valve

G36 Stainless Steel Safety Relief Valves – side outlet discharge with leak proof dome top.

These valves are commonly used for preventing a safe pressure being exceeded in pressurised systems. The lift is proportional to the system overpressure. Particularly suitable for most liquid applications where a ‘small’ discharge often prevents the safe pressure in a system being exceeded. Also suitable for steam, gases & vapour applications where a low discharge is suitable.

Size Range:

  • DN15-DN50 (½” – 2”)

Pressure Range:

  • 0.5 Bar.g (7 PSI) to 20.7 Bar.g (300 PSI)

Pipe Connections:

  • Male Inlet x Female Outlet.
  • Inlet: Threaded ‘G’ BSP Male to BS EN ISO 228/BS 2779
  • Outlet: Threaded ‘Rp’ Parallel Female to BS 21/BS EN 10226/ISO 7
  • Alternative thread standards, i.e. BSPT or NPT are available upon request.
  • Flanged connections also available. Most flange standards can be accommodated.

Features and Benefits:

  • Gresswell Valves are quality assurance approved to BS EN ISO 9001: 2008 and manufactured in accordance with BS EN ISO 4126-1 & BS6759.
  • Full Cat IV PED approval.
  • Only 4 springs are needed to cover the full pressure range.
  • Clear operating and maintenance instructions are supplied with each despatch.
  • Screwed/Flanged or a combination of both are available as standard.
  • See data sheets for Discharge Capacities.

Flow Substance:





Vented systems and unvented systems

Liquid pump relief, pipeline and vessel protection.

Steam boiler, pipeline and vessel protection.

Compressor, pipeline and reciever protection.


All Gresswell Relief Valves are given a hydraulic seat tightness test before leaving the factory and all valves are supplied pre-set. Special tests or witness testing can be arranged at extra cost.