CEN TS 12169-2008 Criteria for the assessment of conformity of a lot of sawn timber《批量锯材合格评定的标准》.pdf

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1、DD CEN/TS12169:2008ICS 79.040NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWDRAFT FOR DEVELOPMENTCriteria for theassessment ofconformity of a lot ofsawn timberThis Draft for Development was published under the authority of the Standards Policy and Strategy Committee on 30 June

2、 2010 BSI 2010ISBN 978 0 580 63519 9Amendments/corrigenda issued since publicationDate CommentsDD CEN/TS 12169:2008National forewordThis Draft for Development is the UK implementation of CEN/TS 12169:2008. It supersedes DD ENV 12169:2000 which is withdrawn.This publication is not to be regarded as a

3、 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 Draft for Dev

4、elopment are requested so that UK experience can be reported to the international organization responsible for its conversion to an international standard. A review of this publication will be initiated not later than 3 years after its publication by the international organization so that a decision

5、 can be 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

6、 an international 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

7、 to Technical Committee B/543, Round and sawn timber.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.Compliance

8、 with a British Standard cannot confer immunity from legal obligations.DD CEN/TS 12169:2008TECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN/TS 12169January 2008ICS 79.040 Supersedes ENV 12169:2000 English VersionCriteria for the assessment of conformity of a lot of sawn timbe

9、rCritres de vrification de la conformit dun lot de bois sci Kriterien zur Konformittsprfung eines Loses SchnittholzThis Technical Specification (CEN/TS) was approved by CEN on 22 October 2007 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After

10、 two years the members of CEN will be requested to submit theircomments, 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 a

11、t national level in an appropriate form. It is permissible 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

12、, 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 United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATION

13、COMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TS 12169:2008: EDD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 2 Cont

14、ents Page Foreword3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Conformity control.6 4.1 Objective.6 4.2 Principle6 4.3 Applicable AQL 6 4.4 Type of inspection .6 5 Sampling.6 5.1 Sampling rules .6 5.2 Single procedure7 5.2.1 Single sampling .7 5.2.2 Double sampli

15、ng9 DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 3 Foreword This document (CEN/TS 12169:2008) has been prepared by Technical Committee CEN/TC 175 “Round and sawn timber”, the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be t

16、he subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes ENV 12169:2000. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announ

17、ce this Technical Specification: Austria, 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, Switzerl

18、and and the United Kingdom. DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 4 Introduction The purpose of this document is to define an inspection system for a lot of sawn timber. This document uses statistical sampling plans found in ISO 2859-1. DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 5 1 Scope This do

19、cument defines the sampling plans and procedures for inspection by attributes (measurable properties) of sawn timber lots exhibiting a homogenous distribution of characteristics. It also gives control regulations and conditions for conformity or non conformity of a lot in view of the agreed specific

20、ation. This document applies to any sawn timber products claimed to comply with specifications defined in the sales contract. It does not cover the spread of different qualities within a grade or between the contracted grades. In case of a dispute, a sampling carried out only by customer or supplier

21、 is not valid as it cannot be guaranteed to be free from manipulation. Furthermore parties are free to enlarge the sampling or make use of another method provided an agreement is made between the interested parties. 2 Normative references The following referenced documents are indispensable for the

22、application of 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 2859-1, Sampling procedures for inspection by attributes Part 1: Sampling plans indexed by acceptable qual

23、ity level (AQL) for lot-by-lot inspection. 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 lot of sawn timber a number of sawn timber pieces of the same thickness and width and the same quality grade NOTE A lot of sawn timber can be, for exam

24、ple: package of sawn timber, truckload, a wagon load or shipload of sawn timber, pile of sawn timber, kiln load. 3.2 acceptable Quality Level (AQL) the maximum percentage of non-conforming pieces of sawn timber that can be considered satisfactory as a process average 3.3 non-conforming piece a piece

25、 which fails to meet the quality requirements 3.4 package a part of a homogeneous lot DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 6 4 Conformity control 4.1 Objective The objective of the inspection is to determine with a high probability whether the lot does not conform to the specifications fixed in

26、 the contract and a complaint seems to be justified. Hence the decision is between “conformity“ and “nonconformity“. 4.2 Principle The control of the lot is carried out on the basis of attributes. The pieces making up the sample are defined as “conforming“ or “nonconforming“. The decision regarding

27、conformity or nonconformity of the lot is made on the basis of the number of nonconforming pieces in comparison to the total number of the pieces in the sample. In the case of simultaneous assessments according to different specifications (e.g. appearance, moisture content, dimensions), the number o

28、f nonconforming pieces is evaluated independently. 4.3 Applicable AQL If no AQL value is defined in the accepted grading rules or in the contract, AQL 10 shall be used. (see Tables 2 and 3) NOTE If in random sampling the maximum number of nonconforming pieces “A“, as defined in the AQL tables is exc

29、eeded, the whole lot will contain, with a probability of more than 90 %, a percentage of nonconforming pieces in excess of the AQL value. 4.4 Type of inspection The inspection, described in this document, is carried out according to ISO 2859-1 (General inspection, normal inspection, reference to Tab

30、le I, II or even III A). Other sampling plans, e.g. reduced or increased inspection, may be used if stipulated by the interested party in the contract or a separate agreement. 5 Sampling 5.1 Sampling rules Sampling is based on the concept of AQL. AQL is generally suitable for trade agreements regard

31、ing conformity. Sampling shall be so that random, for none of the parties to the contract will be able to decide which pieces to be inspected. The minimum number of packages to be opened is shown in Table 1. If for any reason the number of packages given in the table is deemed insufficient (for exam

32、ple a large number of packages which are seen to be defective before they are opened), a larger number of packages may be opened. DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 7 Table 1 Number of packages to be opened Number of packages in the lot Number of packages to be opened 1 2 to 5 6 to 11 12 or m

33、ore 1 2 3 4a aIf these packages do not contain the number of pieces required in Table 2, the necessary additional packages shall be opened. Sampling can be carried out either as single sampling (according to 5.2.1) or as double sampling (according to 5.2.2). Double sampling means that a smaller numb

34、er of pieces than in simple sampling are inspected as a first sampling. This leads to “conformity“, “nonconformity“ or “uncertain“. If result is “uncertain“, a second sampling is carried out and the results added to those of the first sampling. The conformity or nonconformity can be determined. The

35、ways of wrapping and protection timber package during transport varies widely. Sometimes the top layer or pieces in the top layer are used to help protect the other pieces in the package. In such a case, the top layer may, by agreement, be excluded from the sampling. 5.2 Single procedure 5.2.1 Singl

36、e sampling The number of packages to be opened is given in Table 1. Based on the number of pieces in the lot, the total number of pieces to be inspected (sample size) is given in Table 2. By dividing the sample size by the number of packages to be opened, determine the number of test pieces per pack

37、age, rounding the result down to the nearest whole number. If the total number of pieces, as calculated, does not agree exactly with the number given in Table 2, the extra piece(s) has (have) to be selected at random in opened packages (only one per package). The first piece to be assessed in each p

38、ackage is selected at random in the top layer. Then, each layer is scanned from left to right according to a frequency of inspection obtained by dividing the total number of pieces in the package by the number of pieces to be inspected ; the result is round down to the nearest whole number. The numb

39、er of nonconforming pieces in different packages is cumulated. The Column A of Table 2 allows to determine the conformity of the lot. EXAMPLE An example is given in Figure 1, where a lot consisting of 3 600 pieces in 15 packages is inspected. Therefore, in accordance with Table 1, four packages are

40、opened. In accordance with Table 2, AQL 10, 125 pieces are inspected or 31 pieces per package (which makes 124 pieces, so take an extra piece at random from one of the packages). As there are 240 pieces in each package, every eighth piece is inspected (240/31, rounded). In Figure 1, every eighth pie

41、ce gave 30 pieces, so one extra piece is selected at random. If out of the 125 sample pieces more than 21 are nonconforming (see Table 2) the lot is nonconforming. Otherwise the lot is conforming. DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 8 Figure 1 Selecting pieces in a package Key 1) First piece s

42、elected at random 2) Extra piece to reach the requested number Table 2 Single sampling - Sample sizes and maximum numbers of nonconforming pieces Pieces in the lot AQL 4 AQL 6,5 AQL 10 S A S A S A 100 to 150 151 to 280 281 to 500 501 to 1200 1201 to 3200 3201 to 10000 10001 to more 20 32 50 80 125 2

43、00 315 2 3 5 7 10 14 21 20 32 50 80 125 200 200 3 5 7 10 14 21 21 20 32 50 80 125 125 125 5 7 10 14 21 21 21 S = Sample size A = Maximum number of nonconforming pieces DD CEN/TS 12169:2008CEN/TS 12169:2008 (E) 9 5.2.2 Double sampling Determine the number of packages to be opened from Table 1. Based

44、on the number of pieces in the lot, determine the total number of pieces to be inspected in the first and second inspections (sample size) by using Table 3, the lines marked “Total“. Carry out the second inspection on a sample taken by the same method as the first. By dividing the sample size by the

45、 number of packages to be opened, determine the number of test pieces per package, the result being down to the nearest whole number. If the total number of pieces, as calculated, does not agree exactly with the number given in Table 3, the extra piece(s) has (have) to be selected at random in opene

46、d packages (only one per package). The first piece to be assessed in each package is selected at random in the top layer. Then, each layer is scanned from left to right according to a frequency of inspection obtained by dividing the total number of pieces in the package by the number of pieces to be

47、 inspected; the result is round down to the nearest whole number. The number of nonconforming pieces in different packages is cumulated. The Column A of Table 3 allows to determine the conformity of the lot. Add the results of the second inspection to the results of the first, and compare the result

48、s with the relevant “Total“ line in Table 3. This determines the status of the whole lot (“conformity“ or “nonconformity“). EXAMPLE A lot consisting of 3 600 pieces is to be inspected. The AQL is 10. According to Table 1, open four packages. Therefore, in accordance with Table 3, select 160 samples.

49、 The first inspection, consisting of 80 samples, shows that 12 pieces are nonconforming. This is between the limits of 11 and 16 pieces, and the result is therefore “uncertain“. A second inspection is therefore necessary. If 11 pieces or less had been nonconforming, the lot would have been conforming at once, and no second inspection would have been necessary. Similarly, if 16 or more pieces had been nonconforming the whole lot would have been nonconforming. Since in the present case a second inspection is necessary, inspect the second 80 samples. This sec