1、 Collection of SANS standards in electronic format (PDF) 1. Copyright This standard is available to staff members of companies that have subscribed to the complete collection of SANS standards in accordance with a formal copyright agreement. This document may reside on a CENTRAL FILE SERVER or INTRA
2、NET SYSTEM only. Unless specific permission has been granted, this document MAY NOT be sent or given to staff members from other companies or organizations. Doing so would constitute a VIOLATION of SABS copyright rules. 2. Indemnity The South African Bureau of Standards accepts no liability for any
3、damage whatsoever than may result from the use of this material or the information contain therein, irrespective of the cause and quantum thereof. ISBN 978-0-626-23551-2 SANS 752:2009Edition 2.6SOUTH AFRICAN NATIONAL STANDARD Float valves Published by SABS Standards Division 1 Dr Lategan Road Groenk
4、loof Private Bag X191 Pretoria 0001 Tel: +27 12 428 7911 Fax: +27 12 344 1568 www.sabs.co.za SABS SANS 752:2009 Edition 2.6 Table of changes Change No. Date Scope Amdt 1 1996 Amended to alter the conditioning temperature for the assembled float valve prior to testing. Amdt 2 2000 Amended to allow fo
5、r two designs of float valves and to add a requirement for the inlet valve to accommodate copper pipe. Amdt 3 2002 Amended to add polyvinyl chloride as optional requirement for plastics material and to update applicable standards. Amdt 4 2004 Amended to delete reference to a requirement and test met
6、hod for noise level in the scope, to update the applicable standards and to change the test method for anti-siphonage. Amdt 5 2007 Amended to change a requirement for the inlet connection of a float valve. Amdt 6 2009 Amended to add a definition for “acceptable” and to renumber the definitions accor
7、dingly, to change the requirements for metallic materials, and to delete a referenced standard. Foreword This South African standard was approved by National Committee SABS SC 138G, Water and sanitation Equipment and systems Plumbing components, in accordance with procedures of the SABS Standards Di
8、vision, in compliance with annex 3 of the WTO/TBT agreement. This document was published in December 2009. This document supersedes SANS 752:2007 (edition 2.5). A vertical line in the margin shows where the text has been technically modified by amendment No. 6. SANS 752:2009 Edition 2.6 1 Contents P
9、age Foreword 1 Scope . 3 2 Definitions 3 3 Requirements . 4 4 Marking 7 5 Inspection and methods of test 7 5.1 Inspection and sequence of tests . 7 5.2 Conditioning 7 5.3 Test on levers 7 5.4 Rate of flow test 7 5.5 Body strength test . 8 5.6 Impact test . 8 5.7 Torque test 8 5.8 Durability test 9 5
10、.9 Anti-siphonage test . 9 5.10 Test for quality of plastics component parts . 10 5.11 Test for dezincification resistance . 10 5.12 Test for attachment of silencing device 10 Appendix A Applicable standards . 11 Appendix B Notes to purchasers 11 Appendix C Quality evaluation of float valves produce
11、d to the requirements laid down in the specification 12 SANS 752:2009 Edition 2.6 2 This page is intentionally left blank SANS 752:2009 Edition 2.6 3 Float valves 1 Scope This specification covers the requirements for two classes, two designs and three types of float valve of nominal size not exceed
12、ing 50 mm that are intended for use with water at a temperature not exceeding 50 C. It does not cover the requirements for floats. NOTE a) The standards referred to in the specification are listed in appendix A. b) Requirements that must be specified by the purchaser are listed in appendix B. c) Inf
13、ormation regarding the verification of the quality of float valves produced to this specification, that could be used to assess compliance with the specification of a lot of float valves, is given in appendix C. 2 Definitions For the purposes of this standard, the following definitions apply: 2.1 ac
14、ceptable acceptable to the authority administering this standard, or to the parties concluding the purchase contract, as relevant Amdt 6 2.2 Amdt 6 equilibrium type float valve whose closing action is unaffected by the pressure of the water in the inlet shank 2.3 Amdt 6 nominal size nominal bore, in
15、 millimetres, of the inlet shank of the float valve 2.4 Amdt 6 pressure-assisted type float valve whose closing action is assisted by means of the pressure of the water in the inlet shank 2.5 Amdt 6 pressure-opposed type float valve whose closing action is resisted by the pressure of the water in th
16、e inlet shank SANS 752:2009 Edition 2.6 4 3 Requirements 3.1 Class and type 3.1.1 Class A float valve shall be of one of the following classes: a) Class HP: Float valves intended for operation at static water pressures not exceeding 2 000 kPa. b) Class LP: Float valves intended for operation at stat
17、ic water pressures not exceeding 600 kPa. 3.1.2 Type A float valve shall be of a pressure-opposed, a pressure-assisted or an equilibrium type. 3.1.3 Design A float valve shall be designed for side entry or for bottom entry. 3.2 Materials 3.2.1 Metallic materials for components in direct contact with
18、 water The metallic material of any component in direct contact with water shall be either a) a copper alloy that, when tested for dezincification resistance in accordance with 5.11, shows a depth of penetration not exceeding 250 m; or b) a stainless steel of an acceptable grade. Amdt 4; amdt 6 3.2.
19、2 Plastics materials All plastics components which are in direct contact with water shall be of polyacetal or polyvinyl chloride (PVC). When tested in accordance with 5.10, plastics components shall show no sign of blistering or weldline splitting. Any surface defects around the injection point shal
20、l not penetrate to a depth greater than 50 % of the thickness of the material at that point. 3.3 Dimensions 3.3.1 Nominal size The nominal size of a float valve shall be 15 mm, 20 mm, 25 mm, 32 mm, 40 mm or 50 mm. 3.3.2 Overall length The overall length of a 15 mm float valve intended for use with a
21、 WC cistern shall not exceed 330 mm measured from the outer face of the fixing flange on the inlet shank to the end of the lever of the assembled float valve in its closed position and without a float. 3.3.3 Floats for float valves A float valve that is supplied without a float shall be designed to
22、be able to operate with a float that complies with SANS 1006. Other float valves shall be supplied complete, fitted with their own design of float. A 15 mm pressure-opposed float valve shall be designed to operate with a 110 mm float. In the case of other sizes of pressure-opposed float valves, the
23、size (nominal diameter) of the float shall be marked on the lever of the float valve (see 4.1(c). Amdt 4 SANS 752:2009 Edition 2.6 5 3.4 Construction 3.4.1 Screw threads The pipe-connecting screw thread on the inlet shank of the body shall be internal or external right-hand thread that complies with
24、 the relevant requirements of SANS 1109-1 for the nominal size of the valve. Amdt 4 3.4.2 Provision for anti-siphonage A float valve shall incorporate means of preventing back siphonage through the float valve. Any air hole incorporated shall discharge downwards. When a float valve is tested in acco
25、rdance with 5.9, the level of the water in the cistern shall not drop. 3.4.3 Attachment of silencing device When a float valve is provided with a silencing device which comprises a separate component that is attached to the float valve, the valve body and the silencing device shall be so connected t
26、hat the device does not become dislodged when tested in accordance with 5.12. 3.4.4 Seats The seat shall be integral with the body, or otherwise, replaceable. 3.4.5 Levers A lever shall a) when tested in accordance with 5.3, not develop a permanent set; b) for a 15 mm or a 20 mm float valve, except
27、when supplied with a float that is attached by means other than an internal thread, be threaded (at the end that will accept the float) with an external thread of useful length at least 10 mm and of size M8; c) be adjustable (to enable the level of the water in a cistern to be altered) by means of a
28、 float adjuster or, in the case of a metal lever on a float valve of nominal size 15 mm, by manual bending, provided that a lever designed for manual bending does not crack or fracture when it is subjected to five cycles of bending by hand (without the aid of tools or other devices), each cycle cons
29、isting of bending the lever through an angle of approximately 45 and then back to its original shape. 3.4.6 Inlet shank The inlet shank shall be furnished with either an integral flange and a back nut or two back nuts to aid in the mounting of the float valve. 3.4.7 Inlet connection Float valves of
30、nominal size 15 mm shall be threaded in accordance with SANS 1306-1. Amdt 5 3.4.8 Stabilizing device A bottom-entry float valve shall incorporate an adjustable and rigid mechanism positioned in such a manner that, when correctly adjusted, it shall prevent any reverse movement of the body of the floa
31、t valve during the closing action of the float and arm. SANS 752:2009 Edition 2.6 6 3.5 Performance 3.5.1 Rate of flow When a float valve is tested in accordance with 5.4, it shall deliver water at the rate given in column 3 of table 1, applicable to the appropriate class and nominal size of float v
32、alve given in column 1, using for the test the lower water pressure given in column 2, provided also that when tested using the higher water pressure for each class of float valve as given in column 2, the water flow rate for a 15 mm valve does not exceed 28 L/min. Table 1 Rate of flow 1 2 3 Class L
33、P float valves Nominal size Water pressure Rate of flow mm 1 %, kPa L/min, min. 15 20 25 100 to 600 100 to 600 100 to 600 5 20 35 32 40 50 100 to 600 100 to 600 100 to 600 200 250 300 Class HP float valves 15 20 25 200 to 1 500 200 to 1 500 200 to 1 500 5 20 35 32 40 50 200 to 1 500 200 to 1 500 200
34、 to 1 500 80 90 100 3.5.2 Body strength When a float valve is tested in accordance with 5.5, it shall not break or suffer any permanent deformation that will affect its operation. 3.5.3 Durability When a float valve is tested in accordance with 5.8, it shall a) operate smoothly and the plunger shall
35、 move freely and not bind during operation; b) not allow water to emerge from any part of the valve except through the normal outlet, the air (anti-siphon) hole, when applicable, and the hinge pin area of the lever; c) not show any sign of damage or deformation; d) not leak at the seat while the val
36、ve is under pressure. 3.5.4 Resistance to torque When a float valve is tested in accordance with 5.7, the inlet shank shall not crack or break, the threads on the shank or on the back nut (or both) shall not strip, and the back nut shall not be forced over the mating thread on the inlet shank. SANS
37、752:2009 Edition 2.6 7 3.5.5 Resistance to impact When the body of a float valve (with any loose covers removed) is tested in accordance with 5.6, it shall not crack or break. 4 Marking 4.1 Each float valve shall bear the following information in legible and indelible marking on the body of the valv
38、e: a) the manufacturers name, trade name or trademark; b) the letters “LP“ in the case of a float valve of class LP and “HP“ in the case of a float valve of class HP; and c) except in the case of a 15 mm float valve, the nominal diameter of the float with which the valve is intended to operate (mark
39、ed on the lever of the valve) (see 3.3.3). 5 Inspection and methods of test 5.1 Inspection and sequence of tests 5.1.1 Inspection Visually examine each float valve for compliance with all the requirements of the specification for which tests to assess compliance are not given in 5.3-5.12 (inclusive)
40、. 5.1.2 Sequence of tests Carry out the tests in 5.3-5.8 (inclusive) in the order in which they are given. 5.2 Conditioning Before conducting the tests, condition the completely assembled float valve by placing it for approximately 72 h in an air oven maintained at a temperature of 60 2 C. Then remo
41、ve the valve from the oven and allow it to cool to approximate ambient temperature. 5.3 Test on levers Remove the lever from the float valve, so rigidly clamp the lever at the end that attaches to the valve that the lever is held horizontal and in an inverted position. Then gradually apply to the fr
42、ee end a vertical load equal to 1,5 times the lifting effort (full buoyancy) of the float with which it is intended to operate. Maintain the test load for 3 min and then remove the load. Examine the lever for compliance with 3.4.5(a). 5.4 Rate of flow test 5.4.1 Equipment a) Mains water supply: A su
43、pply of water which is at a temperature of 20 5 C and is controlled by a flow control valve and which is at a pressure of 2 000 20 kPa. The water shall be delivered through a pipe system terminating in a flow conditioning chamber. b) A flow meter, calibrated and accurate to within 2 % of the flow ra
44、te to be measured. SANS 752:2009 Edition 2.6 8 c) Flow conditioning chamber: A steel pipe of length at least 500 mm and having an inside diameter of approximately 70 mm and having both ends reduced to a size appropriate to the valve under test. The centre of the pipe shall be furnished with a pressu
45、re gauge and an air bleed cock. 5.4.2 Procedure So connect the flow meter and the float valve to the water supply that the flow meter will measure the rate of flow of water delivered by the float valve. Ensure that the lever of the float valve is in its fully open position. Turn on the water supply.
46、 So adjust the water supply that the pressure indicated at the flow conditioning chamber is the appropriate pressure for the valve under test (see 3.5.1). Determine the flow rate in litres per minute. In the case of a 15 mm float valve, repeat the test using the higher water pressure. Check for comp
47、liance with 3.5.1. 5.5 Body strength test Connect the inlet shank of the float valve to a water supply at a pressure of 3 000 100 kPa, the water flow being controlled by a control valve. Using any convenient means, keep the float valve closed at the seat and open the control valve. After 30 s close
48、the control valve and examine the float valve for compliance with 3.5.2. 5.6 Impact test 5.6.1 Equipment a) Tank: A rigidly secured open tank or cistern in which the float valve under test can be fitted as in normal use. b) Sphere: A solid steel ball of mass 500 10 g. 5.6.2 Procedure Install the flo
49、at valve (without a float and lever) in the tank, clamp it, and hand-tighten the back nut as far as it will go. So drop the steel ball three times, from a height of 1,0 m, that it strikes the body of the float valve (not the inlet shank) at a distance of 12 mm from the body flange or from the end of the thread on the inlet shank, as relevant. Examine the float valve for compliance with 3.5.5. 5.7 Torque test 5.7.1 Equipment a) Tank: As in 5.6.1(a). b) Clamp: A rigidly mounted clamp (or similar device) by means of which any movement of the body of a float valve secur
