Installation Problems for Fire Sprinkler Systems

Fire sprinkler systems that are designed, installed, and maintained properly are a very effective means of property protection, life safety protection, and fire fighter safety.  The documented reliability is also high for these systems.  Reality is not quite the same though.  Statistics and documented reliability do not include in-depth investigations that often produce different results and yield design, installation, and inspection, testing, and maintenance failures.

The National Fire Protection Association statistics that are generally reported and quoted are derived from National Fire Incident Reporting System reports (NFIRS), usually not field investigations.  NFIRS reports are often written before in-depth investigations are completed, or in some instances before the investigation is started.

What does any of this have to do with fire sprinkler systems?  Fire sprinkler systems are not as reliable as the statistics show and often that difference is because of design and installation errors.

My experiences include plan review of sprinkler system submittals for municipalities and for building owners, fire and other loss investigations associated with fire sprinklers, and inspection of existing sprinkler systems for potential buyers of buildings with existing sprinkler systems (this aspect will be addressed by the author during an October Society of Fire Protection Engineers presentation).  Recently the number of plan reviews I’ve completed has dropped off significantly, but in the last year I have not reviewed a new design that was in compliance with NFPA 13 or NFPA 13R.  Over the fifteen plus years I’ve performed plan reviews the rejection rate is in excess of seventy percent.

With that background it is easy for me to delineate the top issues with new designs and installations.  The following are not in any order relative to frequency or how critical the issue is, but if the design isn’t correct the installation will not make it better.

Water supply.

  1. No water flow test supplied by engineer of record.
  2. Bids without water flow test information.
  3. Old water flow tests (out-of-date).
  4. Flow tests from incorrect locations.
  5. Incorrectly applied formulas from NFPA 291.
  6. C-factor for existing underground mains as if they are always new.

Fire pump.

  1. No suction calculation.
  2. Incorrect suction calculation.
  3. Incorrectly applied fire pump curve.
    • Frequent use of the theoretical pump curve from NFPA 20 not the actual pump curve from the manufacturer.
    • Incorrectly inputting the actual pump curve from the manufacturer.

Design criteria.

  1. No design criteria supplied by the engineer of record.
  2. Failure to obtain accurate Owner’s information.
  3. Failure to request and determine actual fuel load.
    • Commodity classification.
    • Storage configuration.
    • Storage height.
    • Roof/ceiling height.
  4. Incorrect design criteria chosen by the contractors.
  5. Incorrect sprinkler application.
  6. Incorrect design area.
  7. Completely or partially ignoring the existing piping in a new system (e.g. new additions).
    • C-factor for existing piping the same as new.


  1. Incorrect sprinkler for application.
  2. Sprinkler spacing incorrect – frequently.

Hydraulic calculations.

  1. Incorrect k-factors.
  2. Missing nodes that should be flowing.
  3. Missing underground information.
  4. Incorrect design area size and/or shape.

Generally I point out all of these in detail and require that there are revisions and a resubmittal.  I do not take the time to hold the designers hand.  If they don’t know what these are, and after they are pointed out can’t fix them, it is not my job to teach them.  That is their employer’s responsibility and the fact there isn’t an in-house review before submittal is part of the problem.

I had a discussion recently with a National Institute for Certification of Engineering Technologies (NICET) designer who told me she, “Didn’t have enough time in the estimate to go to the job site and document the valve assembly” that included a fire pump and backflow preventer that was drawn incorrectly in the submittal.  This is a long story, but her design firm had been told multiple times that their ‘as-built’ drawings were not as-built and that the backflow preventer had just been replaced as a part of the project.  To top this off, she was using a flow test from an underground main on the opposite side of the building from the fire pump connection and that main was larger than the main the fire pump was connected too.  Additionally, the fire pump test results were reflecting lower pressures than the ‘modeled’ main they were using on the wrong side of the building.  As a Subject Matter Expert (SME) for NICET, as well as a Senior Engineering Technician since 1986, I was shocked that a ‘certified’ designer would tell me that she didn’t have time to verify existing conditions and continue to use the information that I told her was wrong.

One more example: A fire scene investigation, where the sprinklered portion of the partially sprinklered building burned to the ground, revealed a complete lack of survey of the existing water supply by the sprinkler system designer.  You did read that correctly, the sprinklered portion of the partially sprinklered building burned to the ground (and that was by far the majority of the area that did burn to the ground). By the way, that information did not make it into the NFIRS report, nor did the actual cost of the loss in excess of $25,000,000.00. The sprinkler system design included:

  • c=140 for the underground main that was actually over fifty years old.
  • 6” ductile iron pipe for the underground main that was actually over fifty year old 4” pipe.
  • 6” schedule 40 piping from the spigot piece to the new valve assembly that was actually approximately 40 years old with a 3” (water meter) and 4” that included check valves and a strainer (none of these were in the calculations).
  • A new 6” backflow preventer (but that wasn’t available so a 4” was installed).

The questions that were posed, prompting this article included:

  • What are some of the top issues with new installations of fire sprinkler systems?
  • How do you deal with these issues, problems, and concerns?
  • Who usually finds problems with new installations?
  • What other comments do you have regarding problems with new installations of fire sprinkler systems?

In summary, the problems are usually generated from the design, or lack thereof.  They are identified by qualified and experienced plan reviewers or in the field during loss investigations.  The water supply, fuel load, and automatic sprinkler issues (e.g. spacing, wrong k-factors, missing sprinklers in calculations, and more) are not new and will not get better until serious in-house peer review is performed by every contractor before they start fabrication.



ABOUT THE AUTHOR: Scott A. Futrell, PE, FSFPE, CFEI, CFPS, SET, CWBSD, is a fire protection consultant with Futrell Fire Consult & Design, Inc., in Osseo, Minnesota and has over 40 years’ experience designing, specifying, and investigating fire protection systems. He is a Fellow in the Society of Fire Protection Engineers and co-author of “Designers Guide to Automatic Sprinkler Systems.”