Plumbers install, repair and maintain pipes, fixtures and other plumbing equipment used for water distribution and waste water disposal in residential, commercial and industrial buildings. They are employed in maintenance departments of factories, plants and similar establishments, by plumbing contractors, or they may be self-employed. Apprentices are also included in this unit group.

Steamfitters and pipefitters lay out, assemble, fabricate, maintain, troubleshoot and repair piping systems carrying water, steam, chemicals and fuel in heating, cooling, lubricating and other process piping systems. Sprinkler system installers fabricate, install, test, maintain and repair water, foam, carbon dioxide and dry chemical sprinkler systems in buildings for fire protection purposes. Steamfitters, pipefitters and sprinkler system installers are employed in maintenance departments of factories, plants and similar establishments, and by pipefitting and sprinkler system contractors, or they may be self-employed. Apprentices are also included in this unit group.

Gas fitters install, inspect, repair and maintain gas lines and gas equipment such as meters, regulators and heating units in residential, commercial and industrial establishments. They are employed by gas utility companies and gas servicing companies. Apprentices are also included in this unit group.