1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNovember 15, 20061SUBJECT 321OUTLINE OF INVESTIGATIONFORPIPELINE STRAINERSIssue Number: 3NOVEMBER 15, 2006Summary of TopicsThis new issue of SU 321 is being issued through ULs electronicpublishin
2、g 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 the requirements contained in thisStan
3、dard, 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 ULNOVEMBER 15, 2006SUBJECT 3212No Text on This PageUL COPYRIGHTED MATERIAL
4、 NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSGENERAL1 Scope .4CONSTRUCTION2 General 4PERFORMANCE3 Leakage and Hydrostatic Strength 44 Friction Loss .55 Strength of Materials 56 Marking 5NOVEMBER 15, 2006 SUBJECT 321 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED
5、 FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULGENERAL1 Scope1.1 These requirements cover pipeline strainers for fire protection service. These devices are intended foruse in fire service systems such as sprinkler systems installed in accordance with the Standard forSprinkler Sys
6、tems, NFPA 13, and fixed water spray systems installed in accordance with the Standard forWater Spray Fixed Systems, NFPA 15, where protection against clogging of water discharge is needed.CONSTRUCTION2 General2.1 Pipeline strainers for fire protection service shall have a minimum rated working pres
7、sure of 175 psi.2.2 Screen size openings shall be not less than 1/8 nor more than 1/4 inch diameter. Strainers that arecapable of being cleaned under full rated working pressure may have a screen having openings not lessthan 1/16 inch diameter.2.3 The surface area of the screen openings shall be not
8、 less than a ration of 4 to 1 of the cross-sectionalarea of the pipe waterway.2.4 The material for the screen is to be corrosion resistant such as brass, bronze, or stainless steel, sothat corrosion does not decrease the size of the screen openings.PERFORMANCE3 Leakage and Hydrostatic Strength3.1 Th
9、ere shall be no leakage through the body or joints at pressures up to and including twice the ratedworking pressure.3.2 There shall be no failure of parts at pressures of five times the rated working pressure for strainersizes 6 inches and less, and four times for sizes greater than 6 inches.NOVEMBE
10、R 15, 2006SUBJECT 3214UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL4 Friction Loss4.1 The friction loss through a strainer shall not exceed 3 psi at a flowing velocity of 15 feet per secondunless the strainer is marked to indicate the highe
11、r values.5 Strength of Materials5.1 Metallic materials testing is to be performed to determine the tensile strength, yield, and elongation ofmetal castings as well as the chemical analysis of the casting material. The results shall comply with anASTM standard.6 Marking6.1 Each strainer shall be mark
12、ed with the Listees name, pipe size, rated working pressure and year ofmanufacture. The friction loss at 15 feet per second is also to be marked if the results of the friction losstest exceed the minimum specified in paragraph 4.1.NOVEMBER 15, 2006 SUBJECT 321 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULNOVEMBER 15, 2006SUBJECT 3216No Text on This Page
