(a) Where the pressure of gas supplied to domestic, commercial or other low pressure gas piping systems in buildings is in excess of one pound per square inch, an approved gas pressure regulator of sufficient size shall be installed in the service pipe of each such system to prevent pressure in excess of one pound per square inch from being introduced into such building piping.
(b) If located inside a building the above required regulator shall be equipped with a vent pipe leading to the outer air. Means shall be employed to prevent water from entering this pipe and also to prevent stoppage of it by insects or foreign matter.