What Is a PRMS Unit? How a Gas Pressure Regulating & Metering Station Works
Walk past the gas line on almost any industrial site and you'll probably spot a compact steel frame crowded with valves, gauges and a meter. That's usually a PRMS unit.
PRMS is short for Pressure Regulating and Metering Station. Some people call it a pressure reducing and metering station, others just say "the PRMS skid". Whatever the name, it does two jobs. It takes high-pressure gas from the supply and brings it down to a level your equipment can actually use. And it measures every cubic metre that goes through, so the bill matches what you used.
We made a short animated video that follows the gas through our GN-PRMS-025, one component at a time. Here's what it covers.
From 4 bar down to 75 mbar
The inlet. Gas arrives at about 4 bar. A quarter-turn ball valve can isolate the whole station, and a digital gauge right above it shows the incoming pressure.
The Y-strainer. Inside its angled leg is a fine stainless-steel mesh. It catches dust, rust and pipe scale before any of it reaches the regulator or the gas meter. When it needs cleaning, the screen slides out through the end cap.
The slam shut-off valve. Think of this as the station's safety guard. A thin sensing line lets it watch the downstream pressure. If that pressure climbs too high (for example, because the regulator has failed), a spring snaps the valve shut and the gas stops instantly. It stays closed until a technician checks the fault and resets it by hand.
The gas pressure regulator. This is the heart of the PRMS. A flexible diaphragm sits between an adjustable spring above and the outlet pressure below. When demand rises and pressure dips, the valve opens a little more. When demand falls, it eases closed. That constant balancing is what keeps the outlet at a steady 75 mbar.
Purge, relief and drain. A purge valve clears air or gas from the line during commissioning and maintenance. The safety relief valve (SRV) is set just above normal working pressure. If something malfunctions, it opens, vents the excess safely up its own line, then closes again by itself. Below it, a drain valve clears out condensate and debris.
The quantometer. The regulated gas passes a second gauge, then flows through the CPT-01 quantometer. An internal rotor turns with the flow and a magnetic coupling drives the counter on top, recording everything from 2.5 to 25 m³/h.
The solenoid valve. On this unit it's an explosion-proof solenoid valve, built for hazardous areas. While its coil has power, the valve stays open. Cut the power, or trigger a gas leak detector or emergency stop, and it snaps shut. No power, no gas. For standard sites we can supply a non explosion-proof version instead.
The outlet. Test points on the top line allow a final pressure check, and an outlet ball valve isolates the station from the pipework downstream.
Why the skid design matters
Every part is joined with threaded unions and sealing rings on a welded steel frame. That means you can take out one component and replace it without pulling the rest apart. Close the inlet and outlet valves and the whole gas metering skid can be serviced safely, which keeps installation and inspection quick.
Where you'll find one
PRMS units are used for industrial gas distribution, in commercial and industrial buildings, for process heating, and to feed boilers and burners. Anywhere you need steady pressure and an accurate meter reading, a PRMS earns its place.
Watch the five-minute explainer
Prefer YouTube? Watch it here: PRMS Unit Explained: How a Gas Pressure Regulating & Metering Station Works. It's worth five minutes if you're specifying a PRMS for a project.
Need a PRMS unit in Dubai, elsewhere in the UAE, or in Oman? Take a look at the GN-PRMS-025 and ask us for a quote.