, Inspection, Testing, and Maintenance of Fire Sprinklers, Harrington Group IncOnce the correct fire sprinkler is chosen and installed, it must be inspected, tested, and maintained. Before we get into that, don’t forget to check out our posts “Choosing the Right Fire Sprinkler – Part 1” and “Choosing the Right Fire Sprinkler – Part 2” to learn more about the factors and characteristics that must be considered when choosing a fire sprinkler system for your facility.


Sprinklers should be inspected annually in accordance with NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, Section 5.2.1.

Any sprinkler that shows signs of any of the following should be replaced:

  1. Leakage
  2. Corrosion detrimental to sprinkler performance
  3. Physical damage
  4. Loss of fluid in the glass bulb heat-responsive element
  5. Loading detrimental to sprinkler performance
  6. Paint other than that applied by the sprinkler manufacturer
  7. Loss of fluid in glass-bulb type sprinklers
  8. Manufactured prior to 1920

Any sprinkler that has been installed in the incorrect orientation should be corrected as required, such as by repositioning the sprinkler, branch line, drop, or sprig.

Any Escutcheons and cover plates for recessed, flush, and concealed sprinklers should be replaced with their listed escutcheon or cover plate if found missing during the inspection. If the listed escutcheon or cover plate from a listed assembly is missing and is no longer commercially available, the sprinkler should be replaced and provided with a cover plate or escutcheon that are listed together as an assembly.

Confirm minimum 18-in clearance to storage is maintained below all sprinkler deflectors. Clearance between the deflector and the top of storage should be 36-in or greater for special sprinklers.

Confirm coverage area and spacing provided between sprinklers and between branch lines are within the minimum and maximum allowed by the installation guidelines in NFPA 13, and the manufacturer’s technical data sheet.

Confirm no foreign material or objects are attached or suspended from the sprinklers.

Confirm all sprinklers have proper clearance from walls and other obstructions.

Confirm draft curtain is provided between fast response and standard response sprinklers.

Confirm a supply of spare sprinklers is available at the riser or fire pump room.

Spare sprinklers should be inspected annually to confirm the following:

  1. The correct number and type of sprinklers as required by 4.1.5
  2. A sprinkler wrench for each type of sprinkler as required by
  3. The list of spare sprinklers as required by

There are several conditions that can have a detrimental effect on the performance of sprinklers by adversely impacting water distribution patterns, or insulating thermal elements, which can delay operation, or otherwise render the sprinkler inoperable or ineffective.

Severely corroded or loaded sprinklers should be replaced, because the corrosion or loading could affect the water distribution or other performance characteristics. Corrosion on the seat could prevent the flow of water. Corrosion accumulation elsewhere, such as on the frame or deflector, could affect the spray pattern or delay actuation.

A lightly loaded sprinkler, or sprinklers, with limited corrosion that would not impact sprinkler performance can continue to be used if samples are selected for field service testing based on worst-case conditions and the sample successfully passes field service tests.

If multiple sprinkler actuations occur within a facility without a fire, this might be a sign of exposure to excessive temperatures, sprinkler damage, or excessive corrosion of similar sprinklers installed in that facility. Consideration should be given to replacing sprinklers that are considered representative of the operated sprinklers.

Field Service Testing

A representative sample of sprinklers (not less than four sprinklers or 1% of the number of sprinklers per individual sprinkler sample, whichever is greater) should be submitted to a recognized testing laboratory for field service testing at the following intervals per NFPA 25.

  • Sprinklers at 50 years and every 10 years thereafter
  • Sprinklers at 75 years and every 5 years thereafter
  • Sprinklers (dry) at 10 years and every 10 years thereafter
  • Sprinklers (extra high or greater temperature solder type) 5 years
  • Sprinklers (fast-response) at 20 years and every 10 years thereafter
  • Sprinklers (harsh environments) 5 years

Where one sprinkler within a representative sample fails to meet the test requirement, all sprinklers within the area represented by that sample should be replaced.

We hope that you have found this blog series helpful. If you need assistance with choosing the right fire sprinkler system for your facility, or have questions about the inspection, testing, and maintenance of your current fire protection system, please fill out the contact form below, and one of our fire protection engineers will be in touch with you soon.


NFPA 13 (2016) Standard for the Installation of Sprinkler Systems

NFPA 25 (2107) Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems

FM Data Sheet 2-0 Installation Guidelines for Automatic Sprinklers

FM Data Sheet 3-26 Fire Protection Water Demand for Non-Storage Sprinklered Properties

FM Data Sheet 8-9 Storage of Class 1, 2, 3, 4, and Plastic Commodities