When the gas supply pressure is higher than that at which the branch supply line or gas utilization equipment is designed to operate or varies beyond design pressure limits, a line gas pressure regulator or gas equipment pressure regulator shall be installed. (NFPA 54 5.8.1).
The gas pressure regulator location shall be such that the connections are accessible for servicing. (NFPA 54 5.8.3).
Pressure regulators shall be protected against physical damage.Vent gas pressure regulators as follows:
1. An adequately sized independent vent to the outside of the building shall be provided when the location of the regulator is such that a ruptured diaphragm will cause a hazard. When there is more than one regulator at a location, each regulator shall have a separate vent to the outside (NFPA 54 188.8.131.52 )
2. The vent shall be designed to prevent the entry of water, insects, or other foreign materials that could cause blockage (NFPA 54 184.108.40.206 )
3. The regulator vent shall terminate at least 3 ft (0.9 m) from a source of ignition (NFPA 54 220.127.116.11 )
4. At locations where regulators might be submerged during floods, a special antiflood-type breather vent fitting shall be installed, or the vent line shall be extended above the height of the expected flood waters. (NFPA 54 18.104.22.168 )
5. A regulator shall not be vented to the gas equipment vent, chimney, or exhaust system (NFPA 54 22.214.171.124 )