1、BRITISH STANDARDBS EN ISO 7686:2005Plastics pipes and fittings Determination of opacity The European Standard EN ISO 7686:2005 has the status of a British StandardICS 23.040.20; 23.040.45g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g
2、55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 7686:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2006 BSI 31 January 2006ISBN 0 580 47363 5National forewordThis British Stand
3、ard is the official English language version of EN ISO 7686:2005. It is identical with ISO 7686:2005. It supersedes BS EN 578:1994 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee PRI/88, Plastic piping systems, to Subcommittee PRI/88/4, Method of tests
4、 for plastic piping systems and components, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document
5、may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users
6、 are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change,
7、and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover, an inside front cover, the EN ISO title page, the EN ISO foreword page, the ISO title page, pages ii and iii, a blank page, pag
8、es 1 to 4, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 7686July 2005ICS 23.040.20; 23.040.45 Supers
9、edes EN 578:1993 English VersionPlastics pipes and fittings - Determination of opacity (ISO7686:2005)Tubes et raccords en matires plastiques - Dterminationde lopacit (ISO 7686:2005)Rohre und Formstcke aus Kunststoffen - Bestimmung derOpazitt (ISO 7686:2005)This European Standard was approved by CEN
10、on 20 June 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be
11、 obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central S
12、ecretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Po
13、rtugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedw
14、orldwide for CEN national Members.Ref. No. EN ISO 7686:2005: EEN ISO 7686:2005 Foreword This document (EN ISO 7686:2005) has been prepared by Technical Committee ISO/TC 138 “Plastics pipes, fittings and valves for the transport of fluids“ in collaboration with Technical Committee CEN/TC 155 “Plastic
15、s piping systems and ducting systems“, the secretariat of which is held by NEN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by January 2006, and conflicting national standards shall be withdrawn
16、at the latest by January 2006. This document supersedes EN 578:1993. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland,
17、France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 7686:2005 has been approved by CEN as EN ISO 7686:2005 without
18、 any modifications. Reference numberISO 7686:2005(E)INTERNATIONAL STANDARD ISO7686Second edition2005-07-01Plastics pipes and fittings Determination of opacity Tubes et raccords en matires plastiques Dtermination de lopacitEN ISO 7686:2005ii iiiForeword ISO (the International Organization for Standar
19、dization) is a worldwide federation of national standards bodies (ISO member bodies). The work 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
20、 be represented on that committee. International organizations, governmental and non-governmental, 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 Stan
21、dards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The 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 Int
22、ernational Standard requires approval by at least 75 % of the member bodies casting a vote. 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 7686
23、was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic materials and their accessories Test methods and basic specifications. This second edition cancels and repla
24、ces the first edition (ISO 7686:1992), of which it constitutes a technical revision. It incorporates the following modifications: a note giving the principal reason for measurement of opacity of products has been added to the scope; the use of an integrating sphere for measurement is given as an opt
25、ion; the incident beam is defined with respect to the size of the test piece and the entrance port of the integrating sphere; production of test pieces from the sample is prescribed in greater detail; determination of opacity from a series of measurements on the test pieces is prescribed; editorial
26、changes have been introduced. EN ISO 7686:2005blank1Plastics pipes and fittings Determination of opacity 1 Scope This International Standard specifies a method for the determination of the opacity of plastics pipes and fittings. Annex A gives guidance on the light transmission of opaque pipes and fi
27、ttings. NOTE It is necessary for a pipe or fitting used for water supply which is exposed to visible light during service to be sufficiently opaque to prevent algae growth. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 opacity light energy
28、which has passed through the wall of the test piece, expressed as a percentage of the incident light energy on the test piece 2.2 light intensity I light energy which has passed through the test piece 2.3 maximum light intensity Immaximum light energy received from the light source 3 Principle The s
29、cattered and unscattered light energy of a wavelength of 540 nm to 560 nm passing through a test piece cut from a pipe or fitting is measured and expressed as a percentage of the incident light energy on the test piece. 4 Apparatus 4.1 Photoelectric cell, used such that the response of the reading o
30、r recording apparatus is a linear function of the light intensity, from the maximum intensity Imdown to at least 0,01 Im. The detector shall be mounted at right angles to the optical axis to ensure that all light passing through the sample is measured. An integrating sphere may be used to facilitate
31、 measurements. The incident beam shall be centred on the entrance port and pass along the spheres diameter. EN ISO 7686:20052 If the integrating sphere is used, the internal surface should have a white, diffusely reflecting surface with a reflectance of greater than 70 %. The sphere should include b
32、affles so that neither the incident light flux nor the radiation via the test piece can impinge directly onto the detector. 4.2 Adjustable-power arc or incandescent lamp, the intensity of light of which is constant to 1 %. A filter or other means shall be provided to limit the spectrum of the light
33、to a wavelength of 540 nm to 560 nm, unless the referring standard specifies otherwise. 4.3 Diaphragm and optical lenses, adjusted to obtain a parallel-sided and symmetrical incident beam whose width is adjusted according to the size of the test piece, ensuring that all light is directed onto it, an
34、d small enough to enable all light passing through to be detected by the apparatus used. A rectangular patch of light shone on the axis of the test piece is preferred. It is recommended that the width of the light beam should not extend across more than 0,25 to 0,3 times the outside diameter of the
35、test piece to prevent light leakage around the side of the test piece. The maximum dimension of the light beam should not be more than 0,5 to 0,7 times the diameter of the instrument entrance port. 4.4 Support, arranged so that it maintains the surface of the test piece to be examined perpendicular
36、to the optical axis. 5 Test pieces The thinnest wall product in a manufacturers range shall be tested. Take a suitable length of the pipe, or the fitting to be tested. Cut into four strips, equally spaced around the circumference. If it is difficult to meet the recommendation given for the width of
37、the light beam when used for measurement of small diameter pipe, the test piece may be flattened, provided no significant change in thickness occurs (see the second paragraph of 4.3). 6 Procedure 6.1 Setting up the equipment Check a) the alignment of the installation, b) that the reading given by th
38、e photoelectric cell is zero in the absence of light, ensuring that the photoelectric cell is protected from incident daylight, c) that the reading is 100 % in the light emitted by the luminous source in the absence of the test piece, d) that the reading using an opaque sheet of plastic or other mat
39、erial is of an opacity level of less than 2 %, calibrated by a reference standard, e) the accuracy of the reading, using standard calibrated samples or filters that give an absorption percentage of about 0,2 % an accuracy of at least 0,05 % in the range of 0 to 0,2 % is considered desirable. 6.2 Mea
40、surement 6.2.1 Record the reading of maximum light energy Imreceived from the light source in the absence of the test piece. EN ISO 7686:200536.2.2 Place the test piece on the support (4.4) and position against the detector or integrating sphere port, ensuring that it is positioned centrally with re
41、spect to the light source and perpendicular to it. The convex (outer) surface of the pipe or fitting test piece shall face the light source. NOTE In practice, light will fall on the outer surface of the product and therefore the orientation of the test piece has been chosen to represent a pipe or fi
42、tting in service. 6.2.3 Record the reading of light energy, I, that has passed through the wall of the test piece. 6.2.4 Make three measurements along the length of each of the four test pieces. 7 Determination of opacity 7.1 Calculate the percentage of light transmitted through the test piece using
43、 the following equation: m100II 7.2 Take the mean of the three measurements made on each test piece. 7.3 Take the highest of the mean values determined from the four test pieces as the value of opacity. 8 Test report The test report shall include the following information: a) a reference to this Int
44、ernational Standard and the referring standard; b) all details necessary for complete identification of the test sample (manufacturer, type of product, polymer used, production date); c) the value of opacity, i.e. the percentage of incident light energy transmitted through the test piece; d) any fac
45、tors which may have affected the results, such as incidents or operating details not specified in this International Standard; e) the date of the test. EN ISO 7686:20054 Annex A (informative) Recommended maximum light transmission for opaque pipes and fittings A.1 Recommended limit If the referring
46、standard specifies that the pipe and fittings shall be opaque, the maximum acceptable limit for the amount of light which may pass through the wall of the pipe or fitting should be 0,2 % when determined in accordance with this method. This limit is considered sufficient to suppress the growth of alg
47、ae within such a pipe or fitting. A.2 Calibration The calibration between 1 % and 0,1 % can be checked by using a neutral density filter of a density of between 2,0 and 3,0 (see 6.1). These filters are available from most national calibration laboratories. EN ISO 7686:2005blankBS EN ISO 7686:2005BSI
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49、ed by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions.It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: +44 (0)20 8996 9000. Fax: +44 (0)20 8996 7400.BSI offers members an individual updating service called P
