Case study: Hospital sprinkler system

A retrofit sprinkler system in a hospital required additional waterflow switches

By William E. Koffel, PE, FSFPE, Koffel Associates, Columbia, Md. March 21, 2022
Courtesy: Koffel Associates Inc.

Koffel Associates encountered an unusual situation in the design of a retrofit sprinkler system for a hospital. The client requested additional waterflow switches on the supply loop in the basement of the hospital. The intent of the waterflow switches was to identify possible leaks in that portion of the system piping.

The fire protection design team identified the waterflow switches as supervisory devices because they were being used to identify a potential water leak. During the review process, a comment was generated that those particular waterflow switches should result in an alarm signal.

The team responded to the review comments by saying the intended response was for someone to investigate the source of the signal (a supervisory response). The designer also responded by indicating that the alarm signal would be received by a flow switch closer to the sprinkler that actuated. If one or more of these flow switches also initiated an alarm signal, fire responders would be confused by what would appear to be two or more separate alarm conditions in distinctly separate areas of the building.

With that explanation, the authority having jurisdiction concurred that the waterflow switch should initiate a supervisory signal.


Author Bio: William E. Koffel is president of Koffel Associates. He is chair of the NFPA Correlating Committee on Life Safety and a member of several NFPA technical committees. He is a member of the Consulting-Specifying Engineer editorial advisory board.