The _________ mains directly service a number of branch lines on which sprinklers are installed

• A. Riser
• B. Cross
• C. Feed Main
• D. Branch Line

Answer: (B)

In a fire sprinkler system, water is distributed from a vertical riser through horizontal distribution pipes known as cross mains. These cross mains run along a floor and connect to multiple branch lines that lead to individual sprinklers. Because the branch lines originate from and are fed directly by these horizontal cross mains, they are the pipes that service a number of sprinklers exposed on that floor. The feed main is the larger supply that brings water into the system, while branch lines themselves are the pipes that extend from the cross mains to the sprinklers. Therefore, the cross mains are the ones that directly service multiple branch lines.