| (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.
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