Pumps shall furnish not less than ______ of the total rated head.

Pumps shall furnish not less than ______ of the total rated head.

• A. 50%
• B. 65%
• C. 75%
• D. 60%

Answer: (B)

The idea being tested is how much of the system’s total head a fire pump must provide. In a sprinkler system, the total head needed at design conditions comes from static lift plus friction losses through the piping and fittings. The pump is responsible for generating most of that pressure, while the remaining portion can come from other sources in the system (such as gravity or residual supply pressure) to meet the required head. Not less than 65 percent means the pump must be capable of delivering at least 65% of the total head the system requires. This ensures the pump does most of the work to overcome losses and raise pressure, leaving a predictable portion available from other sources to achieve the full design head. If a smaller fraction were required, the system would rely too much on other sources that may not be dependable during an incident. If a larger fraction were required, the pump might be oversized or more expensive than necessary. For example, if the total head needed at the farthest point is 100 ft, the pump should supply at least 65 ft, with the remaining 35 ft potentially provided by other system components to reach the design head.

The idea being tested is how much of the system’s total head a fire pump must provide. In a sprinkler system, the total head needed at design conditions comes from static lift plus friction losses through the piping and fittings. The pump is responsible for generating most of that pressure, while the remaining portion can come from other sources in the system (such as gravity or residual supply pressure) to meet the required head.

Not less than 65 percent means the pump must be capable of delivering at least 65% of the total head the system requires. This ensures the pump does most of the work to overcome losses and raise pressure, leaving a predictable portion available from other sources to achieve the full design head. If a smaller fraction were required, the system would rely too much on other sources that may not be dependable during an incident. If a larger fraction were required, the pump might be oversized or more expensive than necessary.

For example, if the total head needed at the farthest point is 100 ft, the pump should supply at least 65 ft, with the remaining 35 ft potentially provided by other system components to reach the design head.