1308.10 Backpressure Protection. Protective devices

shall be installed as close to the equipment as practical where the design of the equipment connected is such that air, oxygen, or standby gases are capable of being forced into the gas supply system. Gas and air combustion mixers incorporating double diaphragm “zero” or “atmosphere” governors or regulators shall require no further protection unless connected directly to compressed air or oxygen at pressures of 5 psi (34 kPa) or more. [NFPA 54:5.10.1]

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(2) Discharge stacks or vents shall be designed to pre vent the entry of water, insects, or other foreign material that could cause blockage. The discharge stack or vent line shall be at least the same size as the outlet of the pressure-relieving device. [NFPA 54:5.9.8.1, 5.9.8.2] 1308.7.7 Bypass Piping. Valved and regulated bypasses shall be permitted to be placed around gas line pressure regulators where continuity of service is imperative. [NFPA 54:5.8.6] 1308.7.8 Identification. Line pressure regulators at multiple regulator installations shall be marked by a metal tag or other permanent means designating the building or the part of the building being supplied.

[NFPA 54:5.8.7]

(1) The line pressure regulator for which the relief valve

is providing overpressure protection has failed wide open. (2) The gas pressure at the inlet of the line pressure reg ulator for which the relief valve is providing over

ulator for which the relief valve is providing over bypasses shall be permitted to be placed around gas line

pressure protection is not less than the regulator’s

pressure regulators where continuity of service is imper normal operating inlet pressure. [NFPA 54:5.9.2.5]

ative. [NFPA 54:5.8.6]