Refrigeration fitters install, maintain, and service heating, ventilating and air conditioning (HVAC), and refrigeration systems. Often refrigeration fitters are called upon to service boilers and chillers.

Steamfitters are craftsmen who assemble, install, and maintain piping to carry water, steam, compressed air, gases and fluids needed for processing, manufacturing, heating or cooling.

Plumbers install piping for water, gas and medical gas systems. They also install sanitary facilities such as lavatories, toilets, tubs, bathroom fixtures, showers, kitchen fixtures, drinking fountains, and laundry equipment.