1、January 2009DEUTSCHE NORM English price group 13No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 17.120.20!$UQ%“1504602
2、www.din.deDDIN EN ISO 4373Hydrometry Water level measuring devices (ISO 4373:2008)English version of DIN EN ISO 4373:2009-01Hydrometrie Gerte zur Wasserstandsmessung (ISO 4373:2008)Englische Fassung DIN EN ISO 4373:2009-01www.beuth.deDocument comprises 25 pagesDIN EN ISO 4373:2009-01 2 National fore
3、word This standard has been prepared by Technical Committee ISO/TC 113 “Hydrometric determinations” in collaboration with Technical Committee CEN/TC 318 “Hydrometry” (Secretariat: BSI, United Kingdom). The responsible German body involved in its preparation was the Normenausschuss Wasserwesen (Water
4、 Practice Standards Committee), Technical Committee NA 119-06-10 AA Hydrometrie. The national Organizations for Standardization are obliged to adopt this standard without any modifications. The DIN Standards corresponding to the International Standards referred to in this document are as follows: IS
5、O 772 DIN EN ISO 772 IEC 60079-10 DIN EN 60079-10 IEC 60529 DIN EN 60529 National Annex NA (informative) Bibliography DIN EN ISO 772, Hydrometric determinations Vocabulary and symbols DIN EN 60079-10, Electrical apparatus for explosive gas atmospheres Part 10: Classification of hazardous areas (IEC
6、60079-10:2002) DIN EN 60529, Degrees of protection provided by enclosures (IP code) (IEC 60529:1989 + A1:1999) 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
7、 mesure du niveau de leau (ISO 4373:2008) Hydrometrie - Gerte zur Wasserstandsmessung (ISO 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 Standa
8、rd the status of a national standard without any alteration. Up-to-date lists and bibliographical 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,
9、 German). A version in any other language made by translation under the responsibility of 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, Cz
10、ech 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 United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUR
11、OPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 4373:2008: EContents 2 DIN EN ISO 4373:2009-01 EN ISO 4373:2008 (E
12、) Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Instrument specification .4 4.1 Performance classifications.4 4.2 General4 4.3 Maximum rate of change.5 4.4 Environment.5 4.5 Timing .6 5 Recording .6 5.1 Chart recorders6 5.2 Data loggers .6 6 Enclosure6 7 Installation
13、6 8 Estimation of measurement uncertainty .6 8.1 General6 8.2 Type-A estimation7 8.3 Type-B estimation7 8.4 Level measurement datum .7 8.5 Combining primary measurement uncertainties7 Annex A (informative) Types of water level measuring devices 8 A.1 Reference gauges8 A.2 Peak level gauges. 12 A.3 M
14、echanical float and counterweight gauges. 13 A.4 Air reaction gauges 14 A.5 Electrical pressure transducers 17 A.6 Echo-location, acoustic instruments 18 A.7 Echo-location, radar instruments . 19 A.8 Systems using electrical properties . 20 A.9 Recording devices 21 Bibliography. 23 3 EN ISO 4373:200
15、8 (E) DIN EN ISO 4373:2009-01 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 th
16、e status of a national 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 s
17、ubject of patent 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,
18、 Bulgaria, Cyprus, 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
19、 text of ISO 4373:2008 has been approved by CEN as a EN ISO 4373:2008 without any modification. 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 Int
20、ernational 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 o
21、f this document. 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,
22、Electrical 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 wate
23、r level 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 th
24、e performance 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 we
25、lls. It 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 accou
26、nt in the design of equipment for this purpose. 4 DIN EN ISO 4373:2009-01 EN ISO 4373:2008 (E) The manufacturer has to state the physical principle of the measuring device in order to allow the user to judge the devices suitability for the proposed environment. Table 1 Performance classes of water l
27、evel 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 1,0 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 cha
28、nge 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 sheet and in the instruction manual: a) the maximum rate of change which the instrument can follow without damage; b) the maxim
29、um 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 level 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
30、.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; Temperature class 3: 0 C to +50 C. 4.4.3 Relative humidity Water level measuring devices shall operate within the following rel
31、ative humidity classes: Relative humidity class 1: 5 % to 95 % including condensation; Relative humidity class 2: 10 % to 90 % including condensation; Relative humidity class 3: 20 % to 80 % excluding condensation. 5 EN ISO 4373:2008 (E) DIN EN ISO 4373:2009-01 4.5 Timing 4.5.1 General Where timing,
32、 either analogue or digital, is part of 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 t
33、iming devices used in water level measuring 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
34、of a period of 30 days, within the range 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 d
35、ue to atmospheric variables. NOTE Chart 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
36、 of four digits per reading. Where a data 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
37、 whether or not any parts in contact with 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 in
38、stallation of water level measuring devices. 6 DIN EN ISO 4373:2009-01 EN ISO 4373:2008 (E) 8 Estimation of measurement uncertainty 8.1 General The uncertainty of a value derived from primary measurements may be due to a) unsteadiness of the value being measured (waves on the water surface), or b) r
39、esolution 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 for relating the dispersion of values to the probability of “closeness” to mean value. 8.2 Ty
40、pe-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 estimations can be readily computed from continuous measurements when the dispersion is not masked by h
41、ysteresis 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 measurement process for which large numbers of measurements are not available or to a measurement
42、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
43、a rectangular distribution; dispersions with most measurements congregated about the mean value would have a triangular distribution. Allocation of probability distributions is described in Annex A. The relationship between the uncertainty of primary measurements and the value of the uncertainty of
44、the result is derived from the formula defining the relationship between the value and its primary measurements. Sensitivities are the partial derivatives of the value with respect to each primary measurement. In the case of level, its relationship to primary measurement is generally linear. Sensiti
45、vity coefficients would then be equal to 1. 8.4 Level measurement datum Level measurement is not absolute measurement; it is always relative to a datum, for example a local benchmark or the elevation of a weir crest. The uncertainty associated with the datum should be combined with the uncertainty o
46、f the derived value. 8.5 Combining primary measurement uncertainties To determine the uncertainty of the derived value, U, it is necessary to combine the uncertainties of all primary measurements, u, thus, ()( )( )22level level datum level measurementUu u=+ This illustrates the method when combining
47、 the uncertainty of a reference level datum value. Other components of measurement uncertainty are added by inclusion of their squared value within the brackets. 7 EN ISO 4373:2008 (E) DIN EN ISO 4373:2009-01 Annex A (informative) Types of water level measuring devices A.1 Reference gauges A.1.1 Sta
48、ff and ramp gauges A.1.1.1 Description A staff gauge (see Figure A.1) comprises a scale marked on, or securely attached to, a suitable vertical. Where the range of water levels exceeds the capacity of a single vertical gauge, other gauges may be installed in the line of a cross-section normal to the
49、 direction of flow. The scales on such a series of stepped staff gauges should overlap by not less than 15 cm. Dimensions in millimetres Key A detachable plate for metre numeral, coloured red B 10 mm divisions Figure A.1 Staff gauge A ramp gauge (see Figure A.2) consists of a scale marked on, or securely attached to, a suitable inclined surface, which conforms closely to the contour of the riverbank. Throughout its length, the ramp gauge may lie on one continuous slope or may be a compound of two or more slopes. The ramp gauge should lie on the lin
