Which of the following should be considered when sizing pump discharge for standpipe and combination systems?

• A. System Demand
• B. Hydraulic friction losses
• C. Acreage of building
• D. Number of employees

Answer: (A)

Sizing pump discharge centers on meeting the system demand—the total flow rate the standpipe and hose system must deliver to support all outlets simultaneously. The pump needs to provide enough gallons per minute to satisfy the most hydraulically demanding scenario, so the discharge rating is set by that required flow.

Hydraulic friction losses come into play as part of the pressure needed to push that flow through the piping, fittings, and elevation changes; they determine the pump head (pressure) required, not the basic discharge volume. Building acreage and number of employees don’t directly set the required fire flow, whereas system demand reflects the actual demand the system must meet.