Gas expansion is normal in pressure regulating parts of gas installations. At large pressure drops, occurrence of ice in gas is possible which can lead to severe damage on equipment.
To prevent damage of that kind, before pressure reduction gas is heated in heat exchanger. Heating medium is hot water heated up to 90/70°C in boiler-room, separate part of gas regulating station.
It is highly recommended usage of safety shut-off valves as protection from penetration of gas into heating water system.