《BS-EN-ISO-4373-2008.pdf》由会员分享,可在线阅读,更多相关《BS-EN-ISO-4373-2008.pdf(28页珍藏版)》请在三一文库上搜索。
1、BS EN ISO 4373:2008 ICS 17.120.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Hydrometry Water level measuring devices (ISO 4373:2008) Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI This Bri
2、tish Standard was published under the authority of the Standards Policy and Strategy Committee on 3 2008 BSI 2008 ISBN 978 0 580 53817 9 Amendments/corrigenda issued since publication DateComments BS EN ISO 4373:2008 National foreword This British Standard is the UK implementation of EN ISO 4373:200
3、8. It supersedes BS 3680-7:2000 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee CPI/113/5, Measuring instruments and equipment. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does no
4、t purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. 0 November Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncon
5、trolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 4373 October 2008 ICS 17.120.20 English Version Hydrometry - Water level measuring devices (ISO 4373:2008) Hydromtrie - Appareils de mesure du niveau de leau (ISO 4373:2008) Hydrometrie - Gerte zur Wasserstandsmessung (IS
6、O 4373:2008) This European Standard was approved by CEN on 4 October 2008. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliog
7、raphical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of
8、 a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Irela
9、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart,
10、 36 B-1050 Brussels 2008 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 4373:2008: E Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 EN ISO 43
11、73:2008 (E) 3 Foreword This document (EN ISO 4373:2008) has been prepared by Technical Committee ISO/TC 113 “Hydrometric determinations“ in collaboration with Technical Committee CEN/TC 318 “Hydrometry” the secretariat of which is held by BSI. This European Standard shall be given the status of a na
12、tional standard, either by publication of an identical text or by endorsement, at the latest by April 2009, and conflicting national standards shall be withdrawn at the latest by April 2009. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
13、 rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cypru
14、s, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 437
15、3:2008 has been approved by CEN as a EN ISO 4373:2008 without any modification. Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 ISO 4373:2008(E) ISO 2008 All rights reserved iii Contents Page Foreword iv 1 Scope . 1
16、 2 Normative references. 1 3 Terms and definitions. 1 4 Instrument specification 1 4.1 Performance classifications 1 4.2 General. 1 4.3 Maximum rate of change 2 4.4 Environment 2 4.5 Timing 3 5 Recording 3 5.1 Chart recorders. 3 5.2 Data loggers 3 6 Enclosure. 3 7 Installation. 3 8 Estimation of mea
17、surement uncertainty 4 8.1 General. 4 8.2 Type-A estimation. 4 8.3 Type-B estimation. 4 8.4 Level measurement datum 4 8.5 Combining primary measurement uncertainties. 4 Annex A (informative) Types of water level measuring devices . 5 A.1 Reference gauges. 5 A.2 Peak level gauges. 9 A.3 Mechanical fl
18、oat and counterweight gauges. 10 A.4 Air reaction gauges 11 A.5 Electrical pressure transducers 14 A.6 Echo-location, acoustic instruments 15 A.7 Echo-location, radar instruments . 16 A.8 Systems using electrical properties. 17 A.9 Recording devices 18 Bibliography. 20 Licensed Copy: London South Ba
19、nk University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 ISO 4373:2008(E) iv ISO 2008 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The wo
20、rk of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governm
21、ental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The
22、main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
23、Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 4373 was prepared by Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 5, Instruments,
24、equipment and data management. This third edition cancels and replaces the second edition (ISO 4373:1995), which has been technically revised. Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 INTERNATIONAL STANDARD I
25、SO 4373:2008(E) ISO 2008 All rights reserved 1 Hydrometry Water level measuring devices 1 Scope This International Standard specifies the functional requirements of instrumentation for measuring the level of water surface (stage), primarily for the purpose of determining flow rates. This Internation
26、al Standard is supplemented by an annex providing guidance on the types of water level measurement devices currently available and the measurement uncertainty associated with them (see Annex A). 2 Normative references The following referenced documents are indispensable for the application of this d
27、ocument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 772, Hydrometry Vocabulary and symbols IEC 60529, Degrees of protection provided by enclosures (IP Code) IEC 60079-10, Electric
28、al apparatus for explosive gas atmospheres Part 10: Classification of hazardous areas 3 Terms and definitions For the purpose of this document, the terms and definitions given in ISO 772 apply. 4 Instrument specification 4.1 Performance classifications The parameters of performance of a water level
29、measuring device shall be described by the classification categories of uncertainty, temperature range and relative humidity so that the overall performance of the equipment may be summarized in three digits. 4.2 General Water level measuring devices shall be classified in accordance with the perfor
30、mance classes given in Table 1 that account for the resolution to be achieved and the limits of uncertainty required over specified ranges. It should be made clear whether these levels of attainment can only be achieved by the use of special works, for example installation within stilling wells. It
31、is also important to remember that in the measurement of stage, uncertainty expressed as a percentage of range gives rise to worst case uncertainty in the determination of stage at low values of stage. This is highly significant for the measurement of low flows and should be taken into account in th
32、e design of equipment for this purpose. Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 ISO 4373:2008(E) 2 ISO 2008 All rights reserved The manufacturer has to state the physical principle of the measuring device in
33、 order to allow the user to judge the devices suitability for the proposed environment. Table 1 Performance classes of water level measuring devices Class Resolution Range Nominal uncertainty Performance class 1 1 mm 2 mm 10 mm 1,0 m 5,0 m 20 m u 0,1 % of range Performance class 2 2 mm 5 mm 20 mm 1,
34、0 m 5,0 m 20 m u 0,3 % of range Performance class 3 10 mm 50 mm 200 mm 1,0 m 5,0 m 20 m u 1 % of range 4.3 Maximum rate of change As water levels may rise and fall rapidly in some applications, in order to provide guidance on suitability, the manufacturer shall state on the equipment specification s
35、heet and in the instruction manual: a) the maximum rate of change which the instrument can follow without damage; b) the maximum rate of change which the instrument can tolerate without suffering a change in calibration; c) the response time of the instrument. 4.4 Environment 4.4.1 General Water lev
36、el measuring devices shall operate within the ranges of temperature in 4.4.2 and the ranges of relative humidity in 4.4.3. 4.4.2 Temperature Water level measuring devices shall operate within the following temperature classes: Temperature class 1: 30 C to +55 C; Temperature class 2: 10 C to +50 C; T
37、emperature class 3: 0 C to +50 C. 4.4.3 Relative humidity Water level measuring devices shall operate within the following relative humidity classes: Relative humidity class 1: 5 % to 95 % including condensation; Relative humidity class 2: 10 % to 90 % including condensation; Relative humidity class
38、 3: 20 % to 80 % excluding condensation. Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 ISO 4373:2008(E) ISO 2008 All rights reserved 3 4.5 Timing 4.5.1 General Where timing, either analogue or digital, is part of
39、the instrument specification, the timing method used shall be clearly stated on the instrument and in the instruction manual. NOTE It is recognized that digital timing is inherently more accurate than analogue timing. 4.5.2 Digital The uncertainty of digital timing devices used in water level measur
40、ing devices shall be within 150 s at the end of a period of 30 days, within the range of environmental conditions defined in 4.4. 4.5.3 Analogue The uncertainty of analogue timing devices used in water level measuring devices shall be within 15 min at the end of a period of 30 days, within the range
41、 of environmental conditions defined in 4.4. 5 Recording 5.1 Chart recorders Where a chart recorder is to be used as the primary source of data, the resolution and uncertainty parameters shall take account of changes in the dimensions of the recording medium due to atmospheric variables. NOTE Chart
42、recorders have been superseded to a large extent by data logging devices. However, they are still used as back-up units or to provide rapid visual assessment of flow changes on site. 5.2 Data loggers A data logger shall be able to store at least the equivalent of four digits per reading. Where a dat
43、a logger includes the interface electronics, the resolution and uncertainty shall relate to the stored value. 6 Enclosure The performance of the enclosure shall be stated in terms of the IP classification system in accordance with IEC 60529. It shall be stated whether or not any parts in contact wit
44、h water are suitable for contact with potable water. It shall be stated whether or not the equipment may be used in a potentially explosive environment in accordance with IEC 60079-10. 7 Installation The manufacturer shall provide clear instructions for the installation of water level measuring devi
45、ces. Licensed Copy: London South Bank University, South Bank University, 30/01/2009 13:41, Uncontrolled Copy, (c) BSI BS EN ISO 4373:2008 ISO 4373:2008(E) 4 ISO 2008 All rights reserved 8 Estimation of measurement uncertainty 8.1 General The uncertainty of a value derived from primary measurements m
46、ay be due to a) unsteadiness of the value being measured (waves on the water surface), or b) resolution of the measurement process (the eyes resolution of submillimetre distance). Two methods of estimation, Type A and Type B, are described in the Guide to the expression of uncertainty in measurement
47、 for relating the dispersion of values to the probability of “closeness” to mean value. 8.2 Type-A estimation A Type-A estimation is determined directly from the standard deviation of a large number of measurements. (Note that the distribution of these results need not be Gaussian.) Type-A estimatio
48、ns can be readily computed from continuous measurements when the dispersion is not masked by hysteresis of the measurement process. Of course, the dispersion must exceed by a significant margin the resolution of the measurement process. 8.3 Type-B estimation A Type-B estimation is assigned to a meas
49、urement process for which large numbers of measurements are not available or to a measurement with defined limits of resolution. To define a Type-B uncertainty, the upper and lower limits of the dispersion or the upper and lower limits of resolution are used to define the limits of a probability diagram whose shape is selected to represent the dispersion, i.e. uniform dispersions would have a rectangular distribution; dispersions with most measurements congregated about the mean value would have a triangular distribution. Alloca
链接地址:https://www.31doc.com/p-3745221.html