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 gas burners@ comfort heating furnaces@ heaters and gas-fired boiler assemblies except watertube boilers having outputs of 10@000 pounds of steam per hour or more. Gas-heating equipment covered by these requirements may be operated without a competent attendant being constantly on duty at the burners while the burners are in operation. Additional installation and operation requirements are available for central-heating gas appliances@ domestic conversion burners@ 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.