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UL offers online tool for testing of fire sprinklers sampled from buildings

For several decades, UL has provided a testing service to assess the operating characteristics of fire sprinklers sampled from sprinkler systems in existing buildings. UL’s online tool that makes it easy for the user of these services to request testing.

Sprinkler System Inspection, Testing and Maintenance

For more than a century, fire sprinklers have proven to be an extraordinarily effective tool for protecting life and property from fire. While it is critical that these systems be properly designed and installed, it is equally important for these systems to be periodically inspected, tested and properly maintained. The National Fire Protection Standard (NFPA) Standard for the Inspection, Testing and Maintenance of Water-Based Fire Protection Systems, NFPA 25 contains detailed inspection, testing and maintenance requirements for fire sprinkler systems. While the focus of this article is on the examination and testing of the sprinklers sampled from the system, this standard is comprehensive in that it includes requirements for all components of a fire sprinkler system. As indicated in NFPA 25, the responsibility for properly maintaining a sprinkler system resides with the owner of the property.

Periodic inspection of field-installed sprinklers is an important element of a comprehensive maintenance program for sprinkler systems. As specified in NFPA 25, sprinklers showing signs of leakage, field painting, damage, unacceptable corrosion or loading are to be replaced. All of these conditions can lead to the degradation of sprinkler performance during a fire condition.

In addition to the periodic inspection of field-installed sprinklers, NPFA 25 also requires replacement or representative sample testing of sprinklers based upon length of service. The frequency of sample testing or replacement depends upon the sprinkler type and installation environment. For example, while many sprinklers do not require testing until they have been in service 50 years, quick response sprinklers are required to be tested after 20 years in service and 10-year intervals thereafter. Due to the relative complex construction of a dry type sprinkler as well as the anticipated aggressive installation environments for many of these sprinklers, dry type sprinklers required to be tested after 10 years of service and 10-year intervals thereafter. It is also noteworthy to highlight the fact that NFPA 25 indicates that sprinklers installed in harsh environmental conditions are to be replaced or representative samples tested on a 5-year basis.

Request for Operational Testing

UL’s program for conducting operational tests on sprinkler samples removed from field installations is intended to assist property owners and other interested parties in assessing the operating characteristics of sprinklers in service. The recent introduction of UL’s online tool for requesting operational testing of sample sprinklers provides a quick, simple means for initiating this process. This tool can be accessed by visiting UL’s website at www.ul.com\fieldsprinklertesting. Following the menu prompts provided within the tool, basic information on the submittal is requested.

As a part of UL’s field sprinkler testing service, identification tags are available for use at no charge. Sprinkler samples submitted for testing should be identified with the name and address of the building’s occupant, type of room environment (office, warehouse, factory, etc.), location of the sample within the building and information on the party submitting the samples for testing. These identification tags can be requested online as well. A photograph of the sprinkler sample identification tag is shown in Figure 1.

Sprinkler sample identification tags are available from UL free of charge.

Sprinkler sample identification tags are available from UL free of charge.

Sprinkler Sample Selection and Testing

The samples selected for testing are to be representative of the sprinklers installed in the system. As noted in NFPA 25, no less than four samples, or one percent of the number of sprinklers per individual sample, whichever is greater, are to be tested. Since UL’s operational testing of sprinklers is destructive, the sprinkler samples removed from the system for testing need to be immediately replaced with new sprinklers.

Each sample received by UL is visually examined before testing to ascertain the sprinkler manufacturer, model or sprinkler identification number, style, type of heat responsive element, temperature rating and year of manufacturer. The condition of the sprinkler is also noted based upon visual evidence of corrosion, loading, leakage, mechanical damage or field painting.

The testing of the sprinklers involves an assessment of the ability of the sprinkler to operate as intended. To conduct this assessment, sprinkler samples are subjected to the Sensitivity-Oven Heat Test as described in the Standard for Automatic Sprinklers for Fire Protection Service, ANSI/UL 199. During this test, the inlet of the sample is pressurized to approximately 5 psig and quickly plunged into an oven that circulates air at a constant temperature and velocity. The actual temperature and air velocity used for the test is selected based upon the temperature rating of the sprinkler. Each sprinkler sample is observed for proper operating characteristics including the release of operating components and time of operation. A diagram of the test oven apparatus is provided in Figure 2.

The UL report of the testing, provided to the submitter of the samples, describes the condition of each sprinkler and results of the operation test as either normal or abnormal. The as-received condition of each sprinkler sample described in the report is based upon UL’s visual examination. The information included in UL’s report is intended to be considered by other parties in determining whether or not other sprinklers within the system require replacement.



While proper inspection, testing, and replacement (as needed) of the sprinklers is only one aspect an effective maintenance program for a fire sprinkler system, it is an important element. The operating characteristics of sprinklers can degrade over time and an effective means to assess the operating characteristics of field installed sprinklers is to conduct representative sample testing. As required in NPFA 25, this testing is to be conducted by a recognized testing laboratory acceptable to the authority having jurisdiction. UL’s program for testing sprinklers sampled from systems is intended to be a valuable tool to assist property owners, inspection authorities and the insurance industry in making important assessments.

For more information, go to www.ul.com

Top image courtesy of Fomtec

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Kerry M. Bell is Principal Engineer, Fire Sprinkler and Pump Equipment for UL LLC.

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