(a) Gas pressure regulators not incorporating integral vent limiters, and all other gas train components requiring atmospheric air pressure to balance a diaphragm or other similar device, shall be provided with a connection for a vent line.
  (1) The vent lines in subsection (a) shall be:
    (A) sized in accordance with the component manufacturer's instructions; and
    (B) at least the same size as the vent outlet of the device.
  (2) Where there is more than one gas pressure regulator at a location, each gas pressure regulator shall have a separate vent. The vent lines may be manifolded in accordance with accepted engineering practices to minimize back pressure in the event of a diaphragm failure (see subsections (c) and (d)).
  (3) A gas pressure regulator shall not be vented into the boiler flue or exhaust system.
(b) Gas pressure relief valves may discharge into common manifolding only with other gas vent, bleed, or relief lines. When manifolded, the common vent line shall have a cross-sectional area not less than the area of the largest vent line plus 50% of the areas of the additional vent lines.
(c) Atmospheric vent lines, when manifolded, shall be connected into a common atmospheric vent line, having a cross-sectional area not less than the area of the largest vent line, plus 50% of the areas of the additional vent lines.
(d) Atmospheric vent lines shall not be connected to any common or manifolded gas vent, bleed, or relief lines.
(e) All vent and relief lines shall be:
  (1) piped to the outdoors at a safe point of discharge, so there is no possibility of discharged gas being drawn into the air intake, ventilating system, or openings of any structure or piece of equipment;
  (2) shall extend sufficiently above any structure, so that gaseous discharge does not present a fire hazard; and
  (3) a means shall be provided at the terminating point to prevent blockage of the line by foreign material, moisture, or insects.

Source Note: The provisions of this §65.606 adopted to be effective June 15, 2015, 40 TexReg 3121; amended to be effective January 15, 2018, 43 TexReg 75