A fire department connection to a sprinkler system enables firefighters to:

• A. test the system
• B. connect hand lines for attacking the fire
• C. back up the first-attack units
• D. ensure that the pressure of the primary water supply is maintained

Answer: (D)

A fire department connection is used to bring additional water into a building’s sprinkler or standpipe system from an outside source, so the system can keep delivering water as demand rises. By supplying this extra water, firefighters help maintain adequate pressure in the sprinkler system during a fire. That’s why the best choice is that the connection ensures the pressure of the primary water supply is maintained. Testing the system, using hand lines, or simply backing up first-attack units are not the primary roles of the FDC, even though it can aid overall firefighting physics by increasing available water.