Water Fire Suppression Systems

Pressure Relief Valve

Pressure Relief Valve

A pressure relief valve opens and discharges excess water when line pressure exceeds the set value while the fire pump runs at low flow. This protects valves, pipes and sprinklers from the pump’s shut-off pressure.

The store range includes DN80, DN100, DN150 and DN200. It is used especially at diesel fire pump outlets to limit the pressure rise that comes with engine overspeed.

DN80 – DN200size (product range)
Adjustableopening pressure
Pumpoutlet protection
Flangedconnection (by model)

Main Applications

  • Diesel fire pump outlets
  • Pressure limiting on electric pump systems
  • Pump test line returns
  • Fire lines with pressure fluctuations

Technical Data

FunctionOverpressure relief
SizeDN80, DN100, DN150, DN200 (product range)
ConnectionFlanged (by model)
Opening pressureAdjustable (range by model)
ControlPilot or spring (by model)
DischargeTo a waste cone or tank (by design)
MaterialBy model
Pressure classBy model

Material Options

PartRelief valve
BodyBy model
InternalsBy model
Diaphragm / springBy model
ConnectionFlanged (by model)

Which material? The manufacturer datasheet of this relief valve could not be obtained; sizes are taken from store products. The opening pressure is set by the pump curve and system design, and material and class are confirmed by model.

Advantages

Equipment Protection

  • Line protected against overpressure

Adjustable

  • Opening pressure set to the system

Suits Diesel Pumps

  • Limits pressure on overspeed

Large Sizes

  • Up to DN200

Construction and Design Features

  • Closing element that opens at the set pressure
  • Adjusting screw or pilot control
  • Flanged inlet and discharge
  • Connection to the discharge line

Send the pump flow, shut-off pressure and line size; we will define the right relief valve and set range with you.

How to Choose?

  1. Collect pump dataTake flow and shut-off pressure from the pump curve.
  2. Select the sizePick the DN size suited to the relief flow.
  3. Set the opening valueChoose an opening pressure above the system design pressure.
  4. Plan the dischargeRoute the outlet to a waste cone or tank.

Complementary Products

Why ORFA?

Since 1985Over 40 years of experience in supplying industrial piping equipment.
Technical ConsultancyRelief valve size and set-point selection for pump protection.
Delivery from StockDN80–DN200 relief valves in stock shipped immediately.
Pump MatchWe assess the valve against the pump curve and system pressure.
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