This site about union that represents plumbers and pipe, sprinkler, and refrigeration fitters, as well as service technicians. All of these jobs require the installation, remodeling or maintenance of systems that carry water, steam, air and other liquids or gases necessary for sanitation, industrial production, heating and air conditioning, and many other uses. Workers measure, cut, and bend pipe, as well as weld, braze, caulk, solder, glue or thread joints at residential and commercial job sites.