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1、BRITISH STANDARD BS 5728-2: 1980 ISO 4064/II: 1978 Incorporating Amendment No. 1 Measurement of flow of cold potable water in closed conduits Part 2: Specification for installation requirements for single meters. ISO title: Measurement of water flow in closed conduits Meters for cold potable water P
2、art II: Installation requirements UDC 532.542:628.1.033:681.121.002.72 Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5728-2:1980 This British Standard, having been prepared under the direction of the Industrial-process Measurement and C
3、ontrol Standards Committee, was published under the authority of the Executive Board and comes into effect on 30 April 1980 BSI 05-1999 The following BSI references relate to the work on this standard: Committee reference PCL/2 Draft for comment 77/31771 DC ISBN 0 580 11253 5 Cooperating organizatio
4、ns The Industrial-process Measurement and Control Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: British Gas Corporation British Industrial Measuring and
5、 Control Apparatus Manufacturers Association* British Steel Corporation (CBMPE) Council of British Manufacturers of Petroleum Equipment Control and Automation Manufacturers Association (BEAMA) Department of Industry (Computers Systems and Electronics) Electrical, Electronic, Telecommunications and P
6、lumbing Union Electricity Supply Industry in England and Wales Electronic Engineering Association Engineering Equipment Users Association Institute of Measurement and Control Institution of Electronic Engineers Institution of Gas Engineers Oil Companies Materials Association Post Office Engineering
7、Union Scientific Instrument Manufacturers Association Sira Institute The organization marked with as asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Department of Energy (Gas Standards) Depar
8、tment of Industry (National Engineering Laboratory) Institute of Trading Standards Administration Institution of Water Engineers and Scientists National Water Council Amendments issued since publication Amd. No.Date of issueComments 5130July 1986Indicated by a sideline in the margin Licensed Copy: s
9、heffieldun sheffieldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5728-2:1980 0 BSI 05-1999i Contents Page Cooperating organizationsInside front cover National forewordii 1Scope and field of application1 2Criteria for the selection of water meters1 3Associated fittings1 4
10、Installation1 5Special requirements governing the installation of helix type meters known as woltman meters2 6First operation of new or repaired water meters2 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy,
11、(c) BSI BS 5728-2:1980 ii BSI 05-1999 National foreword This British Standard has been prepared under the direction of the Industrial-process Measurement Control Standards Committee and is identical with ISO 4064/II-1978 “Measurement of water flow in closed conduits Meters for cold potable water Par
12、t II: Installation requirements” published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the international standard has been approved as suitable for publication, without deviation, as a British Standard. Some terminology and certain convention
13、s are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Where the words “International Standard” appea
14、r, referring to this standard, they should be read as “British Standard”. The Technical Committee has reviewed the provisions of ISO 4064/1-1977 to which reference is made in the text and has decided that they are acceptable for use in conjunction with this standard. A related British Standard to IS
15、O 4064/1-1977 is BS 5728 “Measurements of flow of cold potable water in closed conduits” Part 1 “Specification for single meters”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Comp
16、liance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may h
17、ave had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5728-2:1980 BSI 05-19991 1 Scope and field of application This International Standar
18、d specifies criteria for the selection of water meters, associated fittings, installation, special requirements for some meters and the first operation of new or repaired meters to ensure accurate constant measurement and reliable reading of the meter. The field of application is as defined in claus
19、e 2 of ISO 4064/1. This International Standard deals only with single-meter installations. Particular requirements dealing with installations including several meters will be specified in an additional document. Where legal requirements exist, they will in all cases take precedence over the specific
20、ations in this International Standard. 2 Criteria for the selection of water meters The type, metrological class and sizes of water meters are determined according to the operating conditions of the installation, taking into account, particularly, the following: the available supply pressure; physic
21、al and chemical characteristics of the water; acceptable pressure loss across the meter; the expected flow rates : the flow rates qmin, qn, qmax of the meter (as defined in clause 3 of ISO 4064/1) must be compatible with the expected flow rate conditions of the installations; the suitability of the
22、meter type for the installation conditions outlined below. 3 Associated fittings The water meter installation shall include the following accessories : 3.1 Upstream side 3.1.1 A stopcock or valve, preferably with the direction of operation indicated. For flanged meters, a full-bore valve. 3.1.2 If r
23、ecommended under clause 5, a flow straightening device and/or a straight length of pipe fitted between the valve and the meter. 3.1.3 If required, a strainer fitted between the stop valve and the meter and, in the case of a helix type meter, upstream of the straight length or the straightening devic
24、e. 3.1.4 If required, a means of sealing the water meter to the water inlet line in order to detect any unauthorized removal of the water meter. 3.2 Downstream side 3.2.1 If required, an adjustable length device to allow for easy installation and removal of the water meter. This device is recommende
25、d for meters with qn $ 15 m3/h. 3.2.2 If required, a device including a drain valve which may be used for pressure monitoring, sterilization and water sampling. 3.2.3 For meters with qn 2,5 m3/h, a stopcock; or a valve; for flanged meters, a full-bore valve, operated in the same sense as the upstrea
26、m valve. 3.2.4 If required, a check valve. 4 Installation 4.1 General requirements 4.1.1 The water meter shall be easily accessible for reading (without the use of mirror or ladder, for instance), for fitting in, for maintenance, for removal and for in situ dismantling of the mechanism if required.
27、In addition, for water meters of mass in excess of 25 kg, clear access to the installation site to allow the water meter to be brought to, or removed from, its working position, and adequate space around the working position for the installation of lifting gear, shall be provided. The following poin
28、ts shall be taken into account: adequate illumination of the installation site is required; flooring shall be clear of obstacles, and shall be even, rigid and not slippery. 4.1.2 All fittings specified in clause 3 shall also be readily accessible and the prescriptions of 4.1.1 relating to large mete
29、rs are also applicable for the fittings. 4.1.3 In all cases, contamination shall be avoided, especially when the meter is installed in a pit, by mounting the water meter and the fittings at a sufficient height above the floor. If necessary, the pit shall be provided with a sump or drain for water re
30、moval. 4.2 Installation requirements 4.2.1 The meter shall be protected from the risk of damage by shock or vibration induced by the surroundings at the place of installation. 4.2.2 The meter shall not be subjected to undue stresses caused by pipes and fittings. If necessary, it shall be mounted on
31、a plinth or bracket. Furthermore, the water pipe lines upstream and down-stream shall be adequately anchored to ensure that no part of the installation can be displaced under water thrust when the meter is dismantled or disconnected on one side. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01
32、 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5728-2:1980 2 BSI 05-1999 4.2.3 The meter shall be protected from the risk of damage by extreme temperature of water and ambient air. 4.2.4 The meter pit shall be protected from flooding and rain water. 4.2.5 The orientation of the meter shall
33、be appropriate to its type. 4.2.6 The meter shall be protected from the risk of damage due to external environmental corrosion. 4.2.7 National legislation and local rules in force concerning the use of water pipes for earthing shall always be consulted. In the case where the water meter is part of a
34、n electrical earthing, in order to minimize the risk to operational staff, there shall be a permanent shunt for the water meter and its associated fittings. 4.2.8 Precautions shall be taken to prevent damage to the meter by unfavourable hydraulic conditions (cavitation, surging, water hammer). 4.2.9
35、 Precautions shall be taken to avoid, if necessary, sudden variation of the flow section close to the meter. 5 Special requirements governing the installation of helix type meters known as woltman meters This type of meter is sensitive to upstream flow disturbances, which cause large errors and prem
36、ature wear. A flow can be subject to two types of disturbances : velocity profile distortion and swirl. Velocity profile distortion is caused typically by an obstruction partially blocking the pipe, for example the presence of a partly closed valve. This effect can be easily minimized. Swirl is caus
37、ed mainly by two or more bends in different planes. This effect can be controlled either by ensuring an adequate length of straight pipe upstream of the meter or, if this is not possible, by installing a straightening device. 6 First operation of new or repaired water meters Before installation, the
38、 water-main shall be flushed to removed debris and the strainer, if fitted, shall be cleaned. After installation, water shall be let into the main slowly and with air bleeds opened so that entrained air does not cause the water meter to race, thereby causing damage. Licensed Copy: sheffieldun sheffi
39、eldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 5728-2:1980 BSI 05-1999 Publications referred to See national foreword. Licensed Copy: sheffieldun sheffieldun, na, Fri Dec 01 14:18:59 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 389 Chiswick High Road London W4 4AL | |
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