1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULFebruary 15, 20081SUBJECT 2573OUTLINE OF INVESTIGATIONFORAUTOMATIC AIR RELEASE AND AIR/VACUUM VALVES FOR FIREPROTECTION SERVICEIssue Number: 1FEBRUARY 15, 2008Summary of TopicsThis first issue of
2、 the Outline of Investigation for Automatic Air Releaseand Air/Vacuum Valves for Fire Protection Service, Subject 2573, coversrequirements for automatic air release valves (vents) and air/vacuumvalves for use in fire pumps or wet pipe automatic sprinkler systems.The UL Foreword is no longer located
3、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:/ 2008 UNDERWRITERS LABORATORIES INC.UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTIO
4、N ORDISTRIBUTION WITHOUT PERMISSION FROM ULFEBRUARY 15, 2008SUBJECT 25732No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULCONTENTSINTRODUCTION1 Scope .42 Units of Measurement .43 Components 44 References .55 Glossary .5CONST
5、RUCTION6 General 57 Rated Pressure .68 Materials .6PERFORMANCE9 General 610 Leakage Test 611 Hydrostatic Strength Test .712 Cycling Test .713 Clogging Test .714 Elastomeric Parts (Except Gaskets) Test .8MANUFACTURING AND PRODUCTION TESTS15 General .916 Production Leakage Tests 9MARKINGS17 General .9
6、INSTALLATION INSTRUCTIONS18 General 10FEBRUARY 15, 2008 SUBJECT 2573 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULINTRODUCTION1 Scope1.1 These requirements cover automatic air release (vents) and air/vacuum valves intended for fireprotecti
7、on service.1.2 Automatic air release valves for use in wet pipe automatic sprinkler systems are intended forinstallation in a sprinkler branch line when it is desired to evacuate air from portions of the sprinkler pipingsystem.1.3 Automatic air release valves for use with fire pumps are intended for
8、 installation on the fire pump tovent entrapped air.1.4 Automatic air/vacuum valves equipped with throttling devices are intended for use with vertical turbinepumps. These valves are intended to release large volumes of air in a controlled manner upon pumpstart-up to reduce air related surges and ad
9、mit air after shutdown, to minimize the development of vacuumconditions within the pump.1.5 Requirements for installation of sprinkler systems are included in the Standard for the Installation ofSprinkler Systems, NFPA 13. Requirements for installation of devices on fire pumps are included in theSta
10、ndard for the Installation of Stationary Pumps for Fire Protection, NFPA 20.2 Units of Measurement2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory orapproximate information.3 Components3.1 Except as indicated in 3.2, a component of a product covered by
11、 this Outline of Investigation shallcomply with the requirements for that component.3.2 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 of Investigati
12、on, orb) Is superseded by a requirement in this Outline of Investigation.3.3 A component shall be used in accordance with its rating established for the intended conditions ofuse.3.4 Specific components are incomplete in construction features or restricted in performance capabilities.Such components
13、 are intended for use only under limited conditions, such as certain temperatures notexceeding specified limits, and shall be used only under those specific conditions.FEBRUARY 15, 2008SUBJECT 25734UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM
14、 UL4 References4.1 Any undated reference to a code or standard appearing in the requirements of this Outline ofInvestigation, shall be interpreted as referring to the latest edition of that code or standard.5 Glossary5.1 For the purpose of this outline, the following definitions apply.5.2 AUTOMATIC
15、AIR RELEASE VALVE (VENT) A device designed to automatically vent into theatmosphere entrapped air that may accumulate at localized high points within a pump or sprinkler pipingsystem while the system is under pressure.5.3 AUTOMATIC AIR/VACUUM VALVE A device designed to automatically release and admi
16、t largevolumes of air during vertical turbine pump start-up and shutdown.5.4 ORIFICE The opening through which the air is expelled.5.5 RATED PRESSURE The maximum working pressure intended to be applied to the inlet of thedevice during end use.5.6 THROTTLING DEVICE A device incorporating an adjustabl
17、e closure element to control therelease of air from an air/vacuum valve.CONSTRUCTION6 General6.1 An automatic air release valve shall have a minimum 1/2-inch (12.7-mm) nominal inlet and outletconnection. An automatic air/vacuum valve shall have a minimum 1-1/2-inch (38.1-mm) nominal inlet andoutlet
18、connection.6.2 Threaded connections shall be in accordance with the Standard for Pipe Threads, General Purpose(Inch), ANSI/ASME B1.20.1, or other national pipe thread standards.6.3 Flange dimensions shall comply with the requirements in the Standard for Gray Iron Pipe Flanges andFlanged Fittings (Cl
19、asses 25, 125, and 250), ANSI/ASME B16.1, or other national pipe flange standards.6.4 An automatic air release valve shall be provided with an orifice size not less than 1/16-inch (1.59-mm)diameter.6.5 An automatic air release valve intended for use on sprinkler branch lines shall be provided with a
20、strainer having a maximum dimension of an opening in the strainer not exceeding 80 percent of theautomatic air release valves orifice diameter. The surface area of the screen openings shall not be lessthan a ratio of 4 to 1 of the cross-sectional area of a Schedule 40 pipe of the same nominal size a
21、s theinlet of the automatic air release valve.FEBRUARY 15, 2008 SUBJECT 2573 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL6.6 Automatic air/vacuum valves shall be equipped with a throttling device to control the release of air.7 Rated Pres
22、sure7.1 An automatic air release or air/vacuum valve shall have a rated pressure of 175 psig (1.21 MPa) orgreater.8 Materials8.1 The body of an automatic air release or air/vacuum valve including throttling device shall beconstructed of a metallic material having corrosion resistance at least equiva
23、lent to cast iron.8.2 Metallic seating surfaces used in an automatic air release or air/vacuum valve shall be constructed ofmaterials with corrosion resistance at least equivalent to brass, bronze, or Series 300 stainless steel.8.3 A strainer for an automatic air release or air/vacuum valve shall be
24、 constructed of materials havingcorrosion resistance at least equivalent to brass, bronze or Series 300 stainless steel.PERFORMANCE9 General9.1 Representative samples of each size automatic air release or air/vacuum valve are to be subjected tothe tests described in these requirements.10 Leakage Tes
25、t10.1 When tested for leakage, automatic air releases and air/vacuum valves shall demonstratecompliance with the following requirements:a) An automatic air release valve intended for use in sprinkler system branch lines shall becapable of withstanding without seat or body leakage an internal hydrost
26、atic pressure of:i) 7 psig (48.3 kPa), andii) Two times the rated pressure when applied for a period of 1 minute at eachpressure.b) An automatic air release or air/vacuum valve intended for use on fire pumps shall becapable of withstanding without seat or body leakage an internal hydrostatic pressur
27、e of:i) 20 psig (138 kPa), andii) Two times the rated pressure when applied for a period of 1 minute at eachpressure.FEBRUARY 15, 2008SUBJECT 25736UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL10.2 A representative sample is to be filled wit
28、h water in a manner that all entrapped air is vented. Theinlet of the device is to be hydrostatically pressurized at a rate not exceeding 300 psig (2.07 MPa) perminute until the applicable test pressures specified in 10.1 are achieved. The test sample is to be visuallyexamined for leakage at the spe
29、cified test pressure.11 Hydrostatic Strength Test11.1 Automatic air releases and air/vacuum valves shall withstand, without rupture of the assembly ordamage to the float, a hydrostatic pressure applied to the inlet equal to four times the rated pressure fora period of 1 minute.11.2 A representative
30、sample is to be filled with water in a manner that all entrapped air is vented. Theinlet of the device is to be hydrostatically pressurized at a rate not exceeding 300 psig (2.07 MPa) perminute until the required test pressure in 11.1 is achieved. The test sample is to be visually examined forruptur
31、e and after the test; the float is to be visually examined for damage or collapse.12 Cycling Test12.1 When subjected to repeated operation of the air release mechanism, automatic air release andair/vacuum valves shall demonstrate compliance with the following requirements:a) An automatic air release
32、 valve intended for use in sprinkler system branch lines shall becapable of withstanding 100 cycles of repeated operation without damage or malfunction, andsubsequently tested to determine compliance with the Leakage Test described in 10.1(a).b) Automatic air releases and air/vacuum valves intended
33、for use on fire pumps shall becapable of withstanding 5000 cycles of repeated operation without damage or malfunction, andsubsequently tested to determine compliance with the Leakage Test described in 10.1(b).12.2 The operating mechanism of the automatic air release valve is to be tested in a manner
34、 so that it ismoved from the open to the closed position, such as by repeated filling and draining of the valve.13 Clogging Test13.1 An automatic air release valve or air/vacuum valve shall operate as intended and show no evidenceof clogging when tested in accordance with 13.2 13.3.13.2 Ten grams of
35、 pipe scale are to be introduced into the body of the test sample as described in Table13.1.FEBRUARY 15, 2008 SUBJECT 2573 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULTable 13.1Contaminant for clogging testSievedesignationa, bNominal siev
36、e opening Grams ofcontaminant (5Percent)inch (mm) Pipe scaleNo. 50 0.0117 (0.297) 2No. 100 0.0059 (0.150) 3No. 200 0.0029 (0.074) 2No. 325 0.0017 (0.043) 3Total 10aSieve designations correspond with those specified in the Standard Specificationfor Wire Cloth and Sieves for Testing Purposes, ASTM E11
37、.bA sieve type intended for this purpose is Cenco-Meinzer, with sieve sizes whichcorrespond with the number designation in this table, and is in compliance withASTM E11; or an equivalent sieve type.13.3 The inlet of a representative sample is to be connected to a 10 ft. (3 m) length of nominal 1/2 i
38、nch(12.7-mm) diameter hose or pipe with a shutoff valve on the opposite end. Initially, the air release valvewith the connected pipe or hose is to contain air only. The shutoff valve is then to be opened allowing theflow of water at a pressure of 100-psig (689 kPa) to enter into the inlet of the hos
39、e and test sample. Visualobservations are to be made for any evidence of clogging and proper operation of the test sample.14 Elastomeric Parts (Except Gaskets) Test14.1 An elastomeric part used to provide a seal shall have the following properties when tested asspecified in the Standard for Gaskets
40、and Seals, UL 157:a) For silicone rubber (with a poly-organo-siloxane as its constituent characteristic), a minimumtensile strength of 500 psi (3.4 MPa) and a minimum ultimate elongation of 100 percent.b) For natural rubber and synthetic rubber other than silicone rubber, a minimum tensilestrength o
41、f 1500 psi (10.3 MPa) and minimum ultimate elongation of 150 percent; or a minimumtensile strength of 2200 psi (15.2 MPa) and a minimum ultimate elongation of 100 percent.c) Those properties relating to maximum tensile set; minimum tensile strength and elongationafter oven aging; and hardness after
42、oven aging, all as specified the Standard for Gaskets andSeals, UL 157. The maximum service temperature used to determine the oven time andtemperature for oven aging is 60C.14.2 The Standard for Gaskets and Seals, UL 157, provides for the testing of either finished elastomericparts or sheets or slab
43、 material. Sheet or slab material is to be tested when the elastomeric parts areO-rings having diameters of less than 1 inch (25.4 mm). The material tested is to be the same as that usedin the product, regardless of whether finished elastomeric parts or sheet or slab material is tested.FEBRUARY 15,
44、2008SUBJECT 25738UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULMANUFACTURING AND PRODUCTION TESTS15 General15.1 The manufacturer shall provide regular production control, inspection, and tests. The program shallinclude at least the Productio
45、n Leakage Tests, Section 16.16 Production Leakage Tests16.1 Each automatic air release valve intended for use in sprinkler branch lines shall not leak at the seator body when subjected to an internal hydrostatic pressure of:a) 7 psig (48.3 kPa) andb) 1.5 times the rated pressure when applied for a p
46、eriod of at least 30 seconds at eachpressure.16.2 Each automatic air release or air/vacuum valve intended for use on fire pumps shall not leak at theseat or body when subjected to an internal hydrostatic pressure of:a) 20 psig (138 kPa) andb) 1.5 times the rated pressure when applied for a period of
47、 at least 30 seconds at eachpressure.16.3 Other production leakage tests shall be permitted to be utilized, when determined to be equivalent.MARKINGS17 General17.1 Each automatic air release or air/vacuum valve shall be permanently marked with the following:a) Manufacturers or private labelers name
48、or identifying symbol.b) Nominal size.c) Model number or the equivalent.d) Rated pressure.e) An arrow indicating the direction of flow or the inlet of the device marked “inlet.”f) Year of manufacture. Air release valves produced in the last three months of a calendar yearshall be permitted to be mar
49、ked with the following year as the date of manufacture.FEBRUARY 15, 2008 SUBJECT 2573 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL17.2 The markings required by 17.1 shall be in raised cast letters, on a permanent stamped metalnameplate, or applied by a method that provides equivalent permanence.17.3 When a manufacturer produces these valves at more than one factory, each device shall have adistinctive marking to identify it as the product of a particular
