1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMarch 4, 20051SUBJECT 260AOUTLINE OF INVESTIGATIONFORAIR PRESSURE MAINTENANCE DEVICESIssue Number 1March 4, 2005Summary of TopicsThis is the first issue of the Subject 260A Outline of Investigati
2、on for AirPressure Maintenance Devices.The UL Foreword is no longer located within the UL Standard. For informationconcerning the use and application of the requirements contained in thisStandard, the current version of the UL Foreword is located onULStandardsInfoNet at: http:/ 2005 UNDERWRITERS LAB
3、ORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMARCH 4, 2005SUBJECT 260A2No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .4
4、2 Components 43 Units of Measurement .44 Undated References 4CONSTRUCTION5 General 5PERFORMANCE6 Leakage and Hydrostatic Strength Tests .57 Reverse Air Flow Test .6MANUFACTURING AND PRODUCTION TESTS8 General 6MARKING9 General 6INSTALLATION INSTRUCTIONS10 General .7MARCH 4, 2005 SUBJECT 260A 3UL COPY
5、RIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 This Outline of Investigation covers devices intended to automatically maintain, within specific limits,the gas pressure in a dry pipe sprinkler system.1.2 The products covered by
6、 this Outline of Investigation are intended for use in sprinkler systemsinstalled in accordance with the Standard for Installation of Sprinkler Systems, NFPA 13.2 Components2.1 Except as indicated in 2.2, a component of a product covered by this outline shall comply with therequirements for that com
7、ponent.2.2 A component is not required to comply with a specific requirement that:a) Involves a feature or characteristic not required in the application of the component in theproduct covered by this outline, orb) Is superseded by a requirement in this outline.2.3 A component shall be used in accor
8、dance with its rating established for the intended conditions ofuse.2.4 Specific components are incomplete in construction features or restricted in performance capabilities.Such components are intended for use only under limited conditions, such as certain temperatures notexceeding specified limits
9、, and shall be used only under those specific conditions.3 Units of Measurement3.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.4 Undated References4.1 Any undated reference to a code or standard appearing in the requirements
10、of this standard shall beinterpreted as referring to the latest edition of that code or standard.MARCH 4, 2005SUBJECT 260A4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONSTRUCTION5 General5.1 An air maintenance device shall have an inlet p
11、ressure rating of not less than 175 psig.5.2 An air maintenance device shall provide a means to sense and maintain outlet air pressure withinpredetermined limits and to a value not greater than 75 psig as specified in the manufacturers installationinstructions.5.3 A 1/8 inch diameter orifice or less
12、 shall be provided to restrict the flow of air through the air pressuremaintenance device, unless the air maintenance device utilizes as small compressor with a flow capacitythat does not exceed 6 scfm. A pressure maintenance device shall be permitted to be provided with abypass line to provide for
13、rapid pressurization of a dry pipe system.5.4 A means, such as a spring loaded check valve, shall be provided to prevent the flow of air from thesprinkler system to the supply source in the event of air supply failure.5.5 A strainer constructed of corrosion resistance materials with openings not exc
14、eeding 80 percent of thediameter of the protected orifice shall be provided.5.6 A pressure regulator used in an air pressure maintenance device intended to regulate downstreamstream air pressure shall comply with the applicable requirements of the Standard for Compressed GasRegulators, UL 252.5.7 A
15、pressure operated switch intended to sense and maintain outlet air pressure shall comply with theapplicable requirements of the Standard for Industrial Control Equipment, UL 508 or the Standard forAlarm Accessories for Automatic Water-Supply Control Valves for Fire Protection Service, UL 753.5.8 Man
16、ual shutoff valves used in an air pressure maintenance device shall comply with the Outline ofInvestigation for Shutoff Valves for Trim and Drain Purposes, Subject 258.PERFORMANCE6 Leakage and Hydrostatic Strength Tests6.1 When tested as specified in 6.2, an air maintenance device assembly shall sho
17、w no evidence ofleakage at twice the rated inlet pressure rating and no rupture at five times the rated inlet pressure rating.6.2 A sample air pressure maintenance test assembly is to be fitted with pipe plugs, filled with water insuch a manner as to exclude all air, and connected to a hydrostatic p
18、ressure source. The pressure is thento be increased to two times the rated pressure and held for 1 minute. Observations are to be made forleakage. The pressure is then to be increase to five times the rated working pressure of the sample, heldfor 1 minute and observations made for rupture of the tes
19、t samples.MARCH 4, 2005 SUBJECT 260A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL7 Reverse Air Flow Test7.1 When tested as specified in 7.2, the device intended to prevent reverse flow of air from the outlet tothe supply source shall seal
20、 promptly and not exhibit leakage when tested from 20 to 75 psig.7.2 The outlet of the reverse flow prevention device shall be connected to a pressure gauge and aregulated air pressure source. The outlet of the reverse flow prevention device shall be supplied with anair pressure of 20 psig and held
21、for 1 minute while observations are made for leakage past the seat. Thistest shall be repeated with initial pressures of 40, 60 and 75 psig. During these tests, observations shallbe made for prompt sealing of the reverse flow mechanism and leakage past the seal as evidenced bythe presence of air bub
22、bles.MANUFACTURING AND PRODUCTION TESTS8 General8.1 To assure compliance with these requirements in production, the manufacturer shall provide thenecessary production control, inspection, and tests.8.2 Each air pressure maintenance device shall be tested for assembly leakage using an air pressure of
23、at least 50 psig.MARKING9 General9.1 An air pressure maintenance device shall be marked with the following:a) Name or trademark of the manufacturer or private labeler.b) Distinctive model number, catalog designation, identification mark, or the equivalent.c) The direction of airflow to system.9.2 Wh
24、en a manufacturer produces an air pressure maintenance device at more than one factory, eachassembly shall have a distinctive marking to identify it as the product of a particular factory.MARCH 4, 2005SUBJECT 260A6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT
25、 PERMISSION FROM ULINSTALLATION INSTRUCTIONS10 General10.1 Each air pressure maintenance device shall be provided with installation instructions that shallinclude at least the following:a) A general description of the components included in the air maintenance device.b) Information on the intended u
26、se including the types of systems to be connected to thedevice.c) Reference to use in accordance with NFPA 13.d) Range for outlet pressure settings and instructions to adjusting the pressure settings in thefield.e) Performance characteristics (such as operating pressure differential) of pressure operatedswitches and pressure regulators when provided.f) Ratings of electrical componentsMARCH 4, 2005 SUBJECT 260A 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMARCH 4, 2005SUBJECT 260A8No Text on This Page
