News | February 4, 2000

Warning: Certain Fire Sprinklers Might Leak or Fail to Operate

Underwriters Laboratories Inc. (UL) is investigating recent field reports that certain "Model GB" series fire sprinklers manufactured by Central Sprinkler Co. of Lansdale, PA may leak or not operate in a fire because they require a higher water pressure to operate than is available in some buildings. The sprinklers under investigation have "O-ring" water seals.

UL strongly recommends to building managers, homeowners, and property owners whose buildings or homes are equipped with these sprinklers that they immediately contact their fire sprinkler service company to assess their fire sprinkler system to determine the appropriate corrective action, including replacement.

The "Model GB" series sprinklers under investigation were introduced in 1988 and are identified by the following prefixes: GB, GB-ALPHA, GB-J, GB-QR, GB-EC, GB-RS, GB-20, GB-20QR, GBR, GB-R1, GB-R2, GBR-LF, GB4, GB4-EC, GB4-FR, GB4-QREC, BB1, BB2, BB3, SD1, SD2, SD3, HIP, ROC, LF, and WS. All of these models may be affected, without regard to the year of manufacture or installation.

However, due to some recent design changes, not all of these models are equipped with "O-ring" water seals. Currently manufactured versions of these models are not equipped with an "O-ring" water seal. Only those models equipped with "O-ring" water seals are under investigation.

Building managers, homeowners and property owners can verify whether their fire sprinkler system is affected by directly contacting their fire sprinkler service company or the sprinkler manufacturer for identification information. Examining the "spare" sprinklers found in the sprinkler cabinet can also usually identify the types of sprinklers used in a fire sprinkler system.

UL's investigation will also seek to determine the cause of the observed elevated operating pressures.

According to UL Vice President Jim Beyreis, "From some of the field samples we've seen, crystallized white or dark-colored deposits or corrosion may be observed around the sprinkler's water seal assembly, indicating that water has leaked past the sprinkler's ‘O-ring' water seal."

The National Fire Protection Association (NFPA) standards require that leaking sprinklers be replaced. UL recommends that these leaking sprinklers be replaced "as soon as possible."

Even if there are no visible signs of leakage, Beyreis said the operation of the "Model GB" series sprinklers in the event of a fire is open to question because they may require higher water pressure to operate than is available in the building(s) involved.

To date, UL's initial testing of approximately 90 samples indicates that approximately 20% of these sprinklers did not operate at a water pressure of 5 pounds per square inch (psi), which is the pressure at which new sprinklers are required to operate in order to earn a UL Listing, nor at 7 psi, which is the pressure that new sprinklers are required to operate in order to meet the NFPA installation requirements.

Although the water pressure available in most buildings exceeds 7 psi, a few sprinkler samples tested by UL did not operate at 60 psi, which exceeds the water pressure that is available in some occupancies, including residences.

"Further testing is warranted. The safest course of action would be to replace these sprinkler models," said Beyreis.

Building owners who desire to have their sprinklers tested should select representative samples of these sprinkler models from the installation and send them to UL for testing. Before representative sprinkler samples are submitted for testing, instructions for the proper removal and packaging procedures for samples from existing sprinkler systems must first be obtained from Central Sprinkler Co.

Once samples have been properly removed and packaged according to the instructions, they may be sent to Kerry Bell at Underwriters Laboratories Inc., 333 Pfingsten Rd., Northbrook, IL 60062 for operational testing. In keeping with its not-for-profit, testing for public safety mission, UL will conduct these operational tests at no cost to the submitter during the course of UL's investigation, with the exception of the expenses associated with the removal, replacement, shipping, and handling of the sprinklers.

Building owners wishing to obtain information concerning these sprinklers or the manufacturer's warranty should contact Central Sprinkler Co., 451 Cannon Avenue, Lansdale, PA or call 1-800-523-6512.

Beyreis said UL is also investigating sprinklers of similar construction. "Fire sprinklers have an excellent field record and have saved countless lives and reduced property damage. We are concerned about the continued reliability of sprinklers equipped with ‘O-ring' water seals, because of recent field reports and the associated test results of these products in UL's laboratories. For these reasons, we recommend that systems incorporating these sprinklers be tested at least annually."

Beyreis noted that UL is considering a proposal to revise the appropriate UL Standards for Safety with respect to the "O-ring" water seals.

UL is an independent, not-for-profit product safety certification organization that has been investigating and Listing automatic sprinklers for fire protection for more than 90 years.

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