UL continues to urge inspection of dry sprinklers: testing offered at no cost

December 28, 2001—Underwriters Laboratories Inc. (UL), the product safety and certification organization, is again reminding property owners whose buildings are equipped with dry sprinklers that have “O-ring” water seals to have samples of those sprinklers inspected and tested immediately. Based on ongoing research, UL has found that these sprinklers may not operate in the event of a fire because they may require higher water pressures to operate than may be available in the building.

UL has tested more than 700 dry sprinkler samples from numerous manufacturers that were removed from more than 100 different installation locations. Approximately 50 percent of the samples tested have required inlet pressures greater than 7 psi to discharge water and approximately 22 percent have required an inlet pressure of greater than 40 psi to discharge water.

UL has also received reports of ice forming within the internal waterway of some dry sprinklers installed within freezers. Based upon the information available, UL engineers believe that ice inside the sprinkler assembly may contribute to undesired sprinkler discharge as well as inhibited sprinkler operation in a fire condition.

Accounting for less than three percent of all installed fire sprinklers, dry sprinklers are generally found in locations with harsh environmental conditions, characterized by wide variations in temperature, humidity and corrosive conditions, such as attics, car ports, cold storage structures, parking garages, warehouses, and unheated portions of buildings.

Central Sprinkler Company has a voluntary replacement program in place for several dry sprinklers including those manufactured by Star Sprinkler Company. The voluntary replacement program represents two of the numerous dry sprinkler manufacturers tested. Additional information regarding this replacement program can be obtained online.

Building managers and property owners can verify whether the sprinklers in question utilize “O-ring” components by contacting the sprinkler manufacturer or UL. Building owners desiring to have installed sprinklers tested should have representative samples of these sprinkler models removed from the installation and sent to UL for testing. UL will conduct these operational tests at no cost to the submitter during the course of UL’s investigation, with the exception of expenses related to sprinkler removal, replacement, shipping and handling.

Before representative sprinkler samples can be submitted to UL for testing, it is important to consult directly with the sprinkler manufacturer or through their customer service representatives for information regarding removal and replacement of the test samples, as well as the applicable terms of the manufacturer’s warranty. Once samples have been properly removed and packaged according to the instructions, sprinkler samples can be sent directly to Kerry Bell at Underwriters Laboratories Inc. (UL), 333 Pfingsten Rd., Northbrook, Ill., 60062. Telephone: 847/664-2629 or e-mail.