1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDecember 5, 20061SUBJECT 723SOUTLINE OF INVESTIGATIONFORDROP-OUT CEILINGS INSTALLED BENEATH AUTOMATIC SPRINKLERSIssue Number: 3DECEMBER 5, 2006Summary of TopicsThis new issue of SU 723S is being
2、issued through ULs electronicpublishing system to ensure format uniformity between the PDF andHTML versions of the document. No substantive changes have beenincorporated in the document.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of
3、the requirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2006 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 5, 2006SUBJECT 723S2No Te
4、xt on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSGENERAL1 Scope .4PERFORMANCE2 General 43 Fire Exposure Test 43.1 Facilities .43.2 Control tests .53.3 Drop-out ceiling tests .53.4 Acceptance criteria .5DECEMBER 5, 2006 SU
5、BJECT 723S 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULGENERAL1 Scope1.1 These requirements cover drop-out ceilings assemblies intended for installation beneath sprinklers.During fire conditions, the drop-out ceiling panels are intended t
6、o drop from their supports to expose thesprinklers to the fire.1.2 Drop-out ceilings covered by these requirements are intended to be installed in accordance withSection 4-4.16 in the Standard for the Installation of Sprinkler Systems, NFPA 13.PERFORMANCE2 General2.1 The installation of drop-out cei
7、lings shall not delay the operation time of automatic sprinklers by morethan 33-1/3 percent, compared with their operation time without the ceiling installed.3 Fire Exposure Test3.1 Facilities3.1.1 The tests are to be conducted in a room having a ceiling height of 15 feet, 9 inches. A ceiling area20
8、 by 18 feet shall be partitioned with vertical plywood baffles extending 4 feet below the ceiling. Thebaffles are to be sealed tightly at a joint. A nominal 1 inch thick (3/4 inch) wood support shall be attachedaround the inside of the baffles such that the top of the support is 2 feet below the tes
9、t room ceiling. Thesprinklers are to be adjusted to the height above the drop-out ceiling recommended by the manufacturer.3.1.2 Four standard pendant automatic sprinklers of the 165 5F rated shall be installed on piping with10 by 10 feet spacing, centered in the 20 by 18 feet area. The sprinkler def
10、lectors shall be 7 2 inch belowthe test room ceiling, and the sprinkler heat responsive elements shall face the center of the test area.The same sprinkler model is to be utilized in all tests.3.1.3 Fire test pans having areas of 7, 5, and 2 square feet shall be placed on the floor and centeredbetwee
11、n the four sprinklers. Two to three inches of denatured alcohol shall be placed into each pan.DECEMBER 5, 2006SUBJECT 723S4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL3.2 Control tests3.2.1 Two control tests are to be conducted to determin
12、e the fire size for the comparative tests. The areaof the alcohol fire shall be selected so that the first sprinkler operates between 2 and 3 minutes afterignition of the alcohol, and the area of the fire shall be selected so that the first sprinkler operates between4 and 5 minutes after ignition of
13、 the alcohol.3.3 Drop-out ceiling tests3.3.1 Following each control test, the drop-out ceiling is to be installed beneath the sprinklers, andevaluated using the test fire areas determined during the control tests.3.3.2 Drop-out ceiling tests shall be conducted at the manufacturers recommended minimu
14、m andmaximum distance beneath the sprinklers using each fire area determined in 3.2.1. As each sprinkleroperates, the water flow shall be adjusted to provide a rate of 15 gallons per minute per sprinkler (0.15gpm/ft2).3.4 Acceptance criteria3.4.1 The sprinkler delay time, calculated following each t
15、est shall not exceed 33-1/3 percent whencalculated as follows:Where:Tc = Time required for the first sprinkler to actuate, with the ceiling installed, andT = Time required for the first sprinkler to actuate, without the ceiling installed.3.4.2 Following each test, the difference between the operatio
16、n time for the last sprinkler and the firstsprinkler shall not have exceeded 300 percent of the time required for the first sprinkler to operate.3.4.3 Following each test, the medium sprinkler operating time for the four sprinklers (the average of theactuation times of the second and third sprinkler
17、s operating) shall not have exceeded 133-1/3 percent ofthe median sprinkler operating time without the drop-out ceiling installed.3.4.4 A minimum of 95 percent of all drop-out ceiling panels, excluding those around the perimeter of the20 by 18 feet (6.1 by 5.5 m) test area, shall drop-out prior to the first sprinkler operation.DECEMBER 5, 2006 SUBJECT 723S 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULDECEMBER 5, 2006SUBJECT 723S6No Text on This Page
