When field acceptance testing a fire pump with a variable speed pressure limiting control, the pump shall be tested in variable speed mode at

According to NFPA 20, the field acceptance test for a fire pump with a variable speed pressure limiting control must be conducted in the variable speed mode. The standard explicitly mandates that the pump's performance be verified at three critical points: no-flow (churn), 100 percent of its rated flow, and 150 percent of its rated flow. This three-point test ensures the pump and its controller can deliver the required performance across the entire operational curve while effectively limiting pressure as designed.

A. This option is incomplete as it omits the 150% rated load test, which is a mandatory point for verifying peak performance.

C. This option includes an additional test point (50%) that is not required by the standard for minimum acceptance criteria.

D. This option lists multiple test points that are not mandated by the standard for acceptance, making the procedure unnecessarily extensive.

1. NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, 2022 Edition, Chapter 14, Section 14.2.6.2.7. This section states, "For pumps with variable speed pressure limiting control, the pump shall be tested in variable speed mode at no flow, 100 percent of rated load, and 150 percent of rated load."