August 29, 2016
Legislative Format Sample Testing of Sprinklers “ESFR sprinklers were sent to UL laboratories to be tested. The results came back with an abnormal activation time on quite a few sprinklers. None of the sprinklers failed to discharge, but some activated in 13 to 17 seconds where 12 seconds is the normal activation time. At what point should all these heads be replaced? If sprinklers that have been in service for over 20 years are not expected to react like a new one, how much extra time is allowed for them to react before we need to consider replacing all the sprinklers in the warehouse?” We have reviewed NFPA 25, 2011 edition that you indicated as the applicable standard. Our informal interpretation is that sprinklers should be replaced when there is a failure. The UL Report on Sprinklers Sampled provided for review states, “UL has completed the sensitivity and functionality testing on samples installed at the referenced location. The results of this testing is intended to assist interested parties including the local Authorities Having Jurisdiction (AHJ) in accessing the operating characteristics of the sprinklers. Please consult the local Authorities Having Jurisdiction (AHJ) regarding the interpretation of the test results described in the attached Test Summary Table(s).” Apparently, the testing laboratory will not indicate “failure” of the sprinkler that was tested. The guidance in 5.3.1.3 says that where one sprinkler within a representative sample fails to meet the test requirement, all sprinklers within the area represented by that sample shall be replaced. A literal interpretation of 5.3.1.3 indicates to replace the sprinklers. The report did not indicate a failure to discharge. The Water-Based Fire Protection Systems Handbook commentary under 5.3.1.1 states, “If the sprinkler fails to operate in the specified amount of time, the sprinkler fails the test and all sprinklers represented by the test sprinkler must be replaced.” This is still ambiguous but it does indicate that some amount reduction is expected. For spray sprinklers, there is a defined amount of delay of 130%. This comes from the allowed amount of delay for new sprinklers to activate following exposure to the corrosion test (see UL 199? Automatic Sprinklers for Fire-Protection Service). Unfortunately, UL 1767 - Early-Suppression Fast-Response Sprinklers does not have a similar identified delay. There has been a recent change to UL 1767 that supports allowing some amount of delay. Previously, UL 1767 restricted the RTI to no more than 36 whereas NFPA 13 defines fast response as 50. The test standard has been changed to allow an RTI of 50 but to be appropriately conservative, a change to a currently listed ESFR sprinkler would require repeating a full scale fire test. The increase in activation time for the change in RTI will be a little over 4.5 seconds. Considering that it is common for identical full scale fire tests to have a 4 or 5 second difference in the activation time for the first sprinkler, it’s reasonable to assume the change to RTI will not noticeably affect the performance. I’s also reasonable to assume that a 4 or 5 second delay in the plunge test should not be considered a failure when testing 20-year old ESFR sprinklers. The annex material in A.5.3.1.1 indicates that the Handbook commentary is excessively conservative by stating sprinklers that have been in service for a number of years should not be expected to have all of the performance qualities of a new sprinkler. However, if there is any question about their continued satisfactory performance, the sprinklers should be replaced. The results should be discussed with the owner or owner’s representative and the AHJ on how to proceed. Since it is not addressed explicitly addressed by NFPA 25, the results should be discussed with the owner or owner’s representative and the AHJ on how to proceed. ------------ Technical Update is prepared by the Technical Services Dept. of the AFSA: Roland Huggins, a PE registered in fire protection engineering, Vice President of Engineering and Technical Services; and Tom Wellen, a PE registered in fire protection engineering. This is provided with the understanding that the AFSA assumes no liability for this opinion or actions taken on it and they are not to be considered the official position of the NFPA or its technical committees. Copyright 2016, American Fire Sprinkler Association. All Rights Reserved. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.firesprinkler.org/private.cgi/sprinklernotes-firesprinkler.org/attachments/20160829/2dd20700/attachment.htm>
