1、DRAFT FOR DEVELOPMENTDD CEN ISO/TS 25377:2007Hydrometric uncertainty guidanceICS 17.120.20g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58DD CEN ISO
2、/TS 25377:2007This Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 30 November 2007 BSI 2007ISBN 978 0 580 57388 0National forewordThis Draft for Development is the UK implementation of CEN ISO/TS 25377:2007. This publication is not to be reg
3、arded as a British Standard.It is being issued in the Draft for Development series of publications and is of a provisional nature. It should be applied on this provisional basis, so that information and experience of its practical application can be obtained.Comments arising from the use of this Dra
4、ft for Development are requested so that UK experience can be reported to the European organization responsible for its conversion to a European standard. A review of this publication will be initiated not later than 3 years after its publication by the European organization so that a decision can b
5、e taken on its status. Notification of the start of the review period will be made in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into a Eur
6、opean Standard, to extend the life of the Technical Specification or to withdraw it. Comments should be sent to the Secretary of the responsible BSI Technical Committee at British Standards House, 389 Chiswick High Road, London W4 4AL.The UK participation in its preparation was entrusted to Technica
7、l Committee CPI/113, Hydrometry.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Amendments issued since publica
8、tionAmd. No. Date CommentsTECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN ISO/TS 25377October 2007ICS 17.120.20English VersionHydrometric uncertainty guidance (HUG) (ISO/TS 25377:2007)Lignes directrices relatives lincertitude en hydromtrie(ISO/TS 25377:2007)Leitfaden zu Mess
9、unsicherheiten in der Hydrometrie (HUG)(ISO/TS 25377:2007)This Technical Specification (CEN/TS) was approved by CEN on 2 August 2007 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit t
10、heircomments, particularly on the question whether the CEN/TS can be converted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible
11、to keep conflicting national standards in force (in parallel to the CEN/TS)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France,
12、 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 STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUN
13、GManagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN ISO/TS 25377:2007: EForeword This document (CEN ISO/TS 25377:2007) has been prepared by Technical Committee CEN/TC 318 “Hyd
14、rometry“, the secretariat of which is held by BSI, in collaboration with Technical Committee ISO/TC 113 “Hydrometric determinations“. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this European Standard: Austr
15、ia, Belgium, 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. CEN ISO/TS
16、 25377:2007Reference numberISO/TS 25377:2007(E)TECHNICAL SPECIFICATION ISO/TS25377First edition2007-10-01Hydrometric uncertainty guidance (HUG) Lignes directrices relatives lincertitude en hydromtrie CEN ISO/TS 25377:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative referenc
17、es . 1 3 Terms and definitions. 1 4 Symbols and abbreviations . 2 5 ISO/IEC Guide 98 (GUM) Basic definitions and rules. 4 5.1 General. 4 5.2 The uncertainty of sets of measurements 4 5.3 Random and systematic effects 4 5.4 Uncertainty models Probability distributions . 5 5.5 Combining uncertainties
18、The law of propagation 5 5.6 Expressing results 6 6 Open channel flow Velocity area methods 6 6.1 General. 6 6.2 Mean velocity, xV . 7 6.3 Velocity-area determination. 8 6.4 Stationary determination of velocity. 9 6.5 Moving determination of velocity 10 6.6 Velocity-area uncertainties 11 6.7 Integra
19、tion uncertainties ()()*,yzuF uF15 6.8 Perimeter flow uncertainties, ()puQ . 16 7 Open channel flow Critical depth methods . 16 7.1 General. 16 7.2 Head and geometry determination 17 7.3 Iterative calculation 18 7.4 Evaluating uncertainty . 18 8 Dilution methods. 18 8.1 General. 18 8.2 Continuous fe
20、ed 19 8.3 Transient mass 20 9 Hydrometric instrumentation 21 9.1 Performance specifications. 21 9.2 Validity of uncertainty statements 21 9.3 Manufacturers performance specifications 22 9.4 Performance guide for hydrometric equipment for use in technical standard examples 23 10 Guide for the draftin
21、g of uncertainty clauses in hydrometric standards . 24 10.1 General. 24 10.2 Equipment, methods and measurement systems. 24 Annex A (informative) Introduction to hydrometric uncertainty . 26 Annex B (informative) An introduction to Monte Carlo Simulation (MCS). 43 Annex C (informative) Performance g
22、uide for hydrometric equipment for use in technical standard examples . 48 Bibliography . 51 CEN ISO/TS 25377:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stand
23、ards 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-governmental, in liaison with ISO, also ta
24、ke 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 main task of technical committees i
25、s 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. In other circumstances, particularl
26、y when there is an urgent market requirement for such documents, a technical committee may decide to publish other types of normative document: an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in an ISO working group and is accepted for publication
27、if it is approved by more than 50 % of the members of the parent committee casting a vote; an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical committee and is accepted for publication if it is approved by 2/3 of the members of the committee casting a v
28、ote. An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed, it is reviewed again after a further three years, at which time it must
29、 either be transformed into an International Standard or be withdrawn. 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/TS 25377 was prepared by t
30、he European Committee for Standardization (CEN) Technical Committee CEN/TC 318, Hydrometry, in collaboration with Technical Committee ISO/TC 113, Hydrometry, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). CEN ISO/TS 25377:2007vIntroduction The manag
31、ement of a natural environment requires knowledge, by measurement, of what is happening. Only then can effective action be taken and the effectiveness of the action assessed. Much depends on the quality of the knowledge itself. The quality of measurable knowledge is stated in terms of measurement un
32、certainty. The internationally agreed method for assessing measurement quality is the Guide to the estimation of uncertainty in measurement (GUM). Without this uniformity of measurement standards, equitable sharing of the environment is not possible and international obligations to care for the envi
33、ronment would be weakened. The essential purpose of the GUM is that a statement of the quality of a measurement result will be presented with all measurements described in technical standards. Without this, no two measurements can be compared or standards set. Whereas the GUM is a reference document
34、 serving the universal requirements of metrology, the Hydrometric uncertainty guidance (HUG) document is specific to hydrometry, i.e. to the measurement of the components of the hydrological cycle. It borrows from the GUM the methods that are the most applicable to hydrometry and applies them to tec
35、hniques and equipment used in hydrometry. In the past, error analysis has provided an indication of measurement quality, but such statements cannot properly convey the quality of the result because it presupposes a knowledge of a true, error-free, value against which the measured result can be compa
36、red. The true value can never be known. Uncertainty therefore remains. For this reason, the GUM uses the concept of uncertainty and uses it for all stages and components of the measurement process. This ensures consistency. The GUM defines standard uncertainty of a result as being equivalent to a st
37、andard deviation. This can be the standard deviation of a set of measured values or of probable values. This is broadly similar to the approach used in error analysis that preceded the uncertainty technique. However, the GUM provides additional methods of estimating uncertainty based on probability
38、models. The two approaches are equivalent but uncertainty requires only a knowledge or estimate of the dispersion of measurement about its mean value, and not the existence of a true value. It is assumed that a careful evaluation of the components of measurement uncertainty brings the mean value clo
39、se to a probable true value, at least well within its margin of uncertainty. In more general terms, uncertainty is a parameter that characterizes the dispersion of measurable values that can be attributed to their mean value. By treating standard deviations and probability models as if they approxim
40、ated to Gaussian (or normal) distributions, the GUM provides a formal methodology for combining components of uncertainty in measurement systems where several input variables combine to determine the result. Within this formal framework, the GUM can be consistently applied to a range of applications
41、 and, thereby, be used to make meaningful comparisons of results. The HUG seeks to promote an understanding of the nature of measurement uncertainty and its significance in estimating the quality of a measurement or a determination in hydrometry. Hydrometry is principally concerned with the determin
42、ation of flow in rivers and man-made channels. This includes environmental hydrometry, i.e. the determination of the flow of natural waters (largely concerned with hydrometric networks, water supply and flood protection), industrial hydrometry, i.e. the determination of flows within industrial plant
43、s and discharges into the natural environment (largely concerned with environment protection and also irrigation). CEN ISO/TS 25377:2007vi Both are the subject of international treaties and undertakings. For this reason, measured data needs to conform to the GUM to assure that results can be compare
44、d. Hydrometry is also concerned with the determination of rainfall, the movement/diffusion of groundwater and the transport by water flow of sediments and solids. This version of the HUG is concerned with flow determination only. The results from hydrometry are used by other disciplines to regulate
45、and manage the environment. If knowledge is required of biomass, sedimentary material, toxins, etc., the concentration of these components is determined and their uncertainty estimated. The uncertainty of mass-load can then be determined from the uncertainty of flow determination. The components of
46、this calculation are made compatible through compliance with the GUM. For practitioners of hydrometry and for engineers, the GUM is not a simple document to refer to. The document has been drafted to provide a legal framework for professional metrologists with a working knowledge of statistical meth
47、ods and their mathematical representation. A helpful document, NIST Technical Note 1297 12, is an abbreviated version of the GUM written to be more accessible to engineers and to specialists in fields other than metrology. The HUG, although simplifying the concepts, in no way conflicts with the prin
48、ciples and methods of the GUM. Accordingly, the HUG interprets the GUM to apply its requirements to hydrometry in a practical way, and, hopefully, in a way accessible to engineers and those responsible for managing the environment. In addition, the HUG introduces and develops Monte Carlo Simulation,
49、 a complementary technique, which has benefits for hydrometry, insomuch as complex measurement systems can be represented realistically. The HUG summarizes basic hydrometric methods defined in various technical standards. The HUG develops uncertainty estimation formulae from the GUM for these basic methods. The basic hydrometric methods described in the HUG may not be identical to those recited in the published technical standards. In such cases, the methods described in these standards are to be taken as authoritative. However, clauses in technical
