A sprinkler fitter specializes in fire suppression systems. Many professionals in this field belong to a local union, which works to ensure fair pay and benefits. In this job, you install and repair the pipes that feed a sprinkler system. Many commercial and residential buildings use these systems, which feature overhead water sprinklers that are activated by heat and smoke. As a sprinkler fitter, your responsibilities involve ensuring that fire sprinklers are installed in appropriate places throughout the building. To do so, you determine the correct size of pipe to use; accurately cut, thread and solder pipes, and secure pipes to the building’s structure using brackets and hangers.