Applies to plumbing operations provided that the work performed is not otherwise classified. Applies to installation, removal or repair of equipment that is used to direct gas or water supplies to a destination. Includes shop work. Refer to code 8227 for a permanent yard maintained by a plumbing contractor and code 5537 for pipe fitting, including the installation of tubing for a refrigeration unit in conjunction with an air conditioning system. The installation of underground sprinkler systems is included code 5183. Trenching work performed by the same contractor is included. Refer to code 6229 for irrigation and drainage systems conducted in connection with lawn sprinkler installations. Applies to pump or boiler installations of a domestic or residential nature, the cleaning and installing of beer drawing equipment, bee coil cleaning, hot water or steam furnace installations, the cleaning of building sewer connections using portable equipment, non electric thermostat installations and installation or service of domestic water softener systems. Contemplates the application of non asbestos insulation to various pipes and equipment. Refer to code 5472 for pipe and boiler work by asbestos contractors, 5188 for automatic sprinkler installation, 3726 for boiler installation or repair, 6306 for sewer construction and 6319 for gas, steam or water main construction.