When designing a manual standpipe system with a fire department pumper, the required pressure at the topmost hose connection is?

• A. 90 psi
• B. 110 psi
• C. 100 psi
• D. 120 psi

Answer: (C)

The test focuses on the prescribed pressure target for the topmost hose connection on a manual standpipe when a fire department pumper supplies the system. NFPA 14 specifies designing the system so that the topmost outlet delivers about 100 psi. This ensures there is enough pressure at the nozzle for effective firefighting after accounting for elevation head and friction losses along the standpipe and hose. The pumper operator adjusts the pump discharge to achieve roughly that 100 psi at the topmost outlet, despite losses.

Choosing 90 psi would risk insufficient nozzle pressure, while 110 or 120 psi is beyond the standard design and can lead to unnecessary over-pressurization. Therefore, 100 psi is the best, standard target.