NFPA - 56
Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems
|Publication Date:||1 January 2020|
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. [54:220.127.116.11(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. [54:18.104.22.168(A)]
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