Current through August, 2024
(a) If the maximum
actual operating pressure of the distribution system is under 60 p.s.i.g. and a
service regulator having the following characteristics is used, no other
pressure limiting device is required:
(1) A
regulator capable of reducing distribution line pressure to pressures
recommended for household appliances;
(2) A single port valve with proper orifice
for the maximum gas pressure at the regulator inlet;
(3) A valve seat made of resilient material
designed to withstand abrasion of the gas, impurities in gas, cutting by the
valve, and to resist permanent deformation when it is pressed against the valve
port;
(4) Pipe connections to the
regulator not exceeding two inches in diameter;
(5) A regulator that, under normal operating
conditions, is able to regulate the downstream pressure within the necessary
limits of accuracy and to limit the build up of pressure under no-flow
conditions to prevent a pressure that would cause the unsafe operation of any
connected and properly adjusted gas utilization equipment;
(6) A self-contained service regulator with
no external static or control lines.
(b) If the maximum actual operating pressure
of the distribution system is 60 p.s.i.g., or less, and a service regulator
that does not have all of the characteristics listed in subsection (a) is used,
or if the gas contains materials that seriously interfere with the operation of
service regulators, there must be suitable protective devices to prevent unsafe
overpressuring of the customer's appliances if the service regulator
fails.
(c) If the maximum actual
operating pressure of the distribution system exceeds 60 p.s.i.g., one of the
following methods must be used to regulate and limit, to the maximum safe
value, the pressure of gas delivered to the customer:
(1) A service regulator having the
characteristics listed in subsection (a), and another regulator located
upstream from the service regulator. The upstream regulator may not be set to
maintain a pressure higher than 60 p.s.i.g. A device must be installed between
the upstream regulator and the service regulator to limit the pressure on the
inlet of the service regulator to 60 p.s.i.g. or less in case the upstream
regulator fails to function properly. This device may be either a relief valve
or an automatic shutoff that shuts, if the pressure on the inlet of the service
regulator exceeds the set pressure (60 p.s.i.g. or less), and remains closed
until manually reset;
(2) A service
regulator and a monitoring regulator set to limit, to a maximum safe value, the
pressure of the gas delivered to the customer;
(3) A service regulator with a relief valve
vented to the outside atmosphere, with the relief valve set to open so that the
pressure of gas going to the customer does not exceed a maximum safe value. The
relief valve may either be built into the service regulator or it may be a
separate unit installed downstream from the service regulator. This combination
may be used alone only in those cases where the inlet pressure on the service
regulator does not exceed the manufacturer's safe working pressure rating of
the service regulator, and may not be used where the inlet pressure on the
service regulator exceeds 125 p.s.i.g. For higher inlet pressures, the methods
in subsection (c)(1) or (2) must be used;
(4) A service regulator and an automatic
shutoff device that closes upon a rise in pressure downstream from the
regulator and remains closed until manually reset.
