G36 General Purpose Pressure Relief Valves

G90 General Purpose Pressure Relief Valves

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: 2015 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.

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.

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.


Gresswell Valves G36 Datasheet G36 Datasheet

Gresswell Valves G36 Discharge Capacities G36 Discharge Capacities