What discharges the water from fire pumps into firemain in single main systems and into cross connects and composite systems?

• A. Risers
• B. Cross connections
• C. Relief valve
• D. Cut out valves

Answer: (A)

Discharge into the firemain from the pump is carried by risers. Risers are the vertical distribution pipes that take water from the firemain and deliver it to outlets on different decks. In a single main system, water from the pump fills the main and then rises through the risers to supply hydrants and hoses. In cross-connected and composite systems, the main water still enters the firemain, and risers carry it upward to feed the various interconnected sections; cross connections simply link different mains to ensure flow, rather than discharging water themselves.

The other options aren’t the path that delivers water from the pump into the system: a cross connection ties separate mains together, a relief valve releases excess pressure, and cut-out valves isolate sections of the system.