Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems - Effective Date: 11/24/2019

Abstract

Applicability.

This standard shall apply to fire and explosion prevention during cleaning and purging activities for new and existing flammable gas piping found in electric-generating plants and in industrial, institutional, and commercial applications.

Coverage of fuel gas piping systems shall extend from the point of delivery or source valve to the gas-consuming equipment isolation valve.

For other than undiluted liquefied petroleum gas (LP-Gas) systems, the point of delivery shall be the outlet of the service meter assembly or the outlet of the service regulator or service shutoff valve where no meter is provided.

[54:1.1.1.1(A)]

For undiluted LP-Gas systems, the point of delivery shall be considered to be the outlet of the final pressure regulator, exclusive of line gas regulators where no meter is installed.

Where a meter is installed, the point of delivery shall be the outlet of the meter.

For facilities that produce flammable gas for consumption on site, the point of delivery or source valve shall be the discharge isolation valve for the gas-producing equipment.

Coverage of flammable gas piping systems other than fuel gas piping systems shall extend from the source valve serving the gas supply system to the gas-consuming equipment isolation valve.

Nonapplication of Standard.

This standard shall not apply to the following items:

(1)* Piping systems covered by NFPA 2

(2)* Piping systems covered by NFPA 51

(3) Fuel-dispensing facilities covered by NFPA 52

(4)* Piping systems covered by NFPA 54

(5)* Piping systems covered by NFPA 55

(6)* Piping systems covered by NFPA 58

(7)* LP-Gas (including refrigerated storage) at utility gas plants (see NFPA 59)

(8)* LNG facilities covered by NFPA 59A

(9)* Vehicle fuel dispensers

(10) Commissioning and maintenance of gas-consuming equipment

(11) Vent lines from pressure relief valves or devices unless such vent lines are also used for purging of flammable gas piping systems

(12)* Systems regulated by U.S. Department of Transportation (DOT) 49 CFR 100–199

(13)* Gathering lines from well pads to gas processing facilities

(14) Well pad piping systems