1.1 These requirements apply to factory-built gas appliances having inputs of more than 400,000 Btu per hour, per individual combustion chamber which require flame failure and other precautions and which are intended primarily for commercial and industrial installation. The appliances covered by these requirements are comfort heating furnaces, heaters and gas-fired boiler assemblies except watertube boilers having outputs of 10,000 pounds of steam per hour or more.

1.2 These requirements also apply to all high pressure steam and high temperature water gas-fired boiler assemblies regardless of Btu per hour input.

1.3 Gas-heating equipment covered by these requirements may be operated without a competent attendant being constantly on duty at the burners while the appliances are in operation.

1.4 Additional installation and operation requirements are available for central-heating gas appliances, floor furnaces, room heaters, unit heaters, and water heaters as defined by the National Fuel Gas Code, NFPA 54, and by the Liquefied Petroleum Gas Code, NFPA 58, as applicable.