NFPA (Fire) 56

Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, 2020 Edition
standard by National Fire Protection Association, 01/01/2020

NFPA (Fire) 850

Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations, 2015 Edition
standard by National Fire Protection Association, 12/01/2014