Sprinkler Age A Publication of the American Fire Sprinkler Association
The debate over horsepower ratings on fire pumps has been heavily debated the last three revision cycles in NFPA 20, and this Technical Review that we received from a member is the exact reason why a hard limit needs to be set on these fire pumps. As noted in the first draft for the 2028 edition of NFPA 20, it is a MINIMUM standard and intended to provide a reasonable degree of protection. Let’s set a reasonable limit on fire pump horsepower ratings and stop overspending on indestructible components with rated conditions well outside the design criteria and expected performance in the field.
You asked the following question(s): Is the intent of NFPA 20, 2019 section 4.7.6 to base wire sizing on 1) the maximum break horsepower for maximum pump load under any flow condition or 2) the horsepower on the name plate of the fire pump?
The following is in response to your question based on AFSA’s Technical Review of NFPA 20, Standard for the Installation of Stationary Pumps for Fire Protection, 2019 edition.
The intent of the standard is that the horsepower on the name plate in accordance with section 4.11.3 is the same as the maximum break horsepower required by section 4.7.6.
4.7.6* The driver shall be selected in accordance with 9.5.2 (electric motors), 11.2.2 (diesel engines), or 13.1.2 (steam turbines) to provide the required power to operate the pump at rated speed and maximum pump load under any flow condition.
4.11.3 The nameplate shall indicate the maximum pump horsepower demand required to power the pump at any flow, including flows beyond 150 percent of the rated capacity.
This interpretation has been debated the last two revision cycles and is being debated this revision cycle for the 2028 edition. As noted in the article provided, this change was not initiated by the technical committee, but from an updated interpretation from the testing laboratories. Prior to 2019, fire pumps were only evaluated up to 150 percent capacity, which is the maximum capacity permitted to be used for design purposes. This creates an issue with pumps installed prior to 2019 that now require replacement and typically require the electrical wiring to be upsized to accommodate the artificially high horsepower rating.
AFSA is actively working to resolve this issue. In the first draft of the 2028 edition of NFPA 20, a committee input was created (CI-33) that would limit the evaluation of the pump to a maximum of 220 percent capacity. A second committee input was created (CI-54), which proposes alternate power requirements for replacement fire pumps. Both CIs have been attached to this newsletter.
AFSA encourages anyone having issued based on the updated interpretation of this requirement to submit a public comment by June 3, 2026 by navigating to nfpa.org/20next.
Click here for the PDF version.
Click here for CI-54 and CI-33
Referenced from AFSA’s Tech Update e-Newsletter, March 30, 2026.