Sprinkler fitting is an occupation consisting of the installing, testing, inspecting, and certifying of  automatic fire suppression systems in all types of structures. Sprinkler systems installed by sprinkler fitters can include the underground supply as well as integrated  systems and standpipes. The fire suppression piping may contain water, air (in a dry system), antifreeze, gas or chemicals as in a hood system, or a mixture producing fire retardant foam.
Sprinkler fitters work with a variety of pipe and tubing materials including several types of plastic, copper, steel, cast iron, and ductile iron.
Sprinkler fitters specialize in piping associated with fire sprinkler systems. The piping within these types of systems are required to be installed and maintained in accordance with strict guidelines in order to maintain compliance with the local building code and the fire code. This type of fire protection is considered a part of active fire protection rather than passive fire protection.