1、 ISO 2017 Timber structures Determination of characteristic values Part 4: Engineered wood products Structures en bois Dtermination des valeurs caractristiques Partie 4: Produits bois reconstitus INTERNATIONAL STANDARD ISO 12122-4 First edition 2017-01 Reference number ISO 12122-4:2017(E) ISO 12122-
2、4:2017(E)ii ISO 2017 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
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4、11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org ISO 12122-4:2017(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Symbols 2 5 Reference population 2 6 Sampling 2 6.1 Sampling method 2 6.2 Sample size . 2 7 Sample conditioning . 2 8 Test data 3 8.1
5、 Test method . 3 8.2 Test data compatible with product description . 3 8.3 Failure modes . 3 9 Evaluation of characteristic values for structural properties . 3 9.1 Structural properties . 3 9.2 Characteristic values of material properties . 3 9.2.1 Characteristic modulus of elasticity and shear mod
6、ulus 3 9.2.2 Characteristic bearing strength 4 9.2.3 Other characteristic values for strength based on the 5th percentile test value 4 9.3 Characteristic values of component properties 4 9.3.1 Characteristic stiffness . 4 9.3.2 Characteristic bearing strength 4 9.3.3 Other characteristic capacities
7、for strength based on the 5th percentile test value . 4 10 Report 4 Annex A (informative) Commentary . 5 Annex B (informative) Analytical models for determining characteristic properties of engineered wood products .10 Bibliography .11 ISO 2017 All rights reserved iii Contents Page ISO 12122-4:2017(
8、E) Foreword ISO (the International Organization for Standardization) 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
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10、ers of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This do
11、cument was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives). 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
12、all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www .iso .org/ patents). Any trade name used in this document is information given for the convenience of use
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14、g URL: www . i s o .org/ iso/ foreword .html. The committee responsible for this document is ISO/TC 165, Timber structures. A list of all the parts in the ISO 12122 series can be found on the ISO website.iv ISO 2017 All rights reserved ISO 12122-4:2017(E) Introduction This document sets out a framew
15、ork for establishing characteristic values from test results on a sample drawn from a clearly defined reference population of engineered wood products. The characteristic value is an estimate of the property of the reference population with a consistent level of confidence prescribed in the standard
16、. This document is intended to be used in conjunction with ISO 12122-1. This document permits the evaluation of characteristic values on testing on commercial engineered wood products. In some cases, characteristic values determined in accordance with this document may be modified to become a design
17、 value. The document has the following annexes: Annex A presents a commentary on this document; Annex B presents information on methods for calculating characteristic values from component properties. ISO 2017 All rights reserved v Timber structures Determination of characteristic values Part 4: Eng
18、ineered wood products 1 Scope This document gives methods of determination of characteristic values for a defined population of engineered wood products calculated from test values. This document presents methods for the determination of a) characteristic value of material properties, where the dete
19、rmined property is multiplied by a geometric parameter to give a component capacity or component stiffness, or b) characteristic value of component properties directly, where the determined property is a component capacity or component stiffness. This document presents methods for determination of a
20、) characteristic value of mean-based properties, and b) characteristic value of 5th percentile-based properties. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references,
21、 only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 12122-1:2014, Timber structures Determination of characteristic values Part 1: Basic requirements 3 T erms a nd definiti ons For the purposes of this documen
22、t, the terms and definitions given in ISO 12122-1 and the following apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p :/ www
23、.iso .org/ obp 3.1 engineered wood product item manufactured from wood, namely plywood, oriented strand board, I beams, laminated veneer lumber or structural insulated panel walls Note 1 to entry: These products that are defined in ISO 12465, ISO 16894, ISO 22389-1, ISO 22390 and ISO 22452. INTERNAT
24、IONAL ST ANDARD ISO 12122-4:2017(E) ISO 2017 All rights reserved 1 ISO 12122-4:2017(E) 4 Symbols Symbols defined in the relevant ISO product or test standard shall be used. Other symbols are defined in ISO 12122-1. 5 Reference population In addition to the requirements for definition of the referenc
25、e population in ISO 12122-1, the following attributes of engineered wood products may be described: a) sources of raw material; b) seasoning method (if seasoned); c) grading or production method for components of the engineered wood product where it is made of previously graded components (including
26、 lamellae); d) specification of adhesives, method of application and method of curing adhesives; e) quality control measures; f) secondary processing, such as preservative treatment, fire retardant treatment, profiling, etc.; g) variations in the configuration of the product (if any). 6 Sampling 6.1
27、 Sampling method The sampling method shall comply with the performance objective of sampling defined in ISO 12122-1. Representation of each of the variants in the sample shall approximate the representation of the same variants in the reference population. See Clause 10 and ISO 12122-1 for reporting
28、 requirements on the sampling method. The report should indicate a response to each of the identified attributes of the reference population listed in compliance with Clause 5 or otherwise important to the description of the reference population. 6.2 Sample size The sample size shall comply with req
29、uirements of ISO 12122-1 and shall take into account the coefficient of variation (V) expected for the sawn timber in the reference population. NOTE 1 See notes under the relevant clause in ISO 12122-1. Engineered wood products properties generally have lower population coefficients of variation (V)
30、 in structural properties and should therefore have a smaller sample size. NOTE 2 ISO 12122-1 gives some guidance on selecting sample size. 7 Sample conditioning The sample storage and testing environment shall reflect conditioning in accordance with the definition of the reference population as ind
31、icated in ISO 12122-1.2 ISO 2017 All rights reserved ISO 12122-4:2017(E) 8 Test data 8.1 Test method The test data shall be obtained from a) tests in accordance with the ISO test standard relevant to the product, or b) a standard test method appropriate for the reference population, provided equival
32、ency factors with the relevant ISO test standard can be established. NOTE See notes under the relevant clause in ISO 12122-1. Test methods involve many variables that will affect results including loading configuration and rates, specimen positioning and measurement methods. The level of precision o
33、f these variables should be appropriate to the objectives of the testing and the adjustments required in 8.2. 8.2 Test data compatible with product description Where the characteristic value is applicable to a standard size or moisture content, adjustments to the test data may be required. Any adjus
34、tment shall be in accordance with ISO 12122-1 and shall be detailed in the report. NOTE These adjustments include those required to pool data from different test programs as outlined in ISO 12122-1. 8.3 Failure modes The failure modes obtained in the tests shall be recorded. The data shall only be i
35、ncluded in the analysis if it comes from a test in which the failure mode appropriate to the property was obtained. NOTE The same test method may produce different failure modes on different products. The characteristic value may be underestimated by tests that produce failure modes that are differe
36、nt to the ones that the test method was intended to produce. 9 Evaluation of characteristic values for structural properties 9.1 Structural properties For engineered wood products, either material properties or component properties shall be evaluated. NOTE 1 Annex A gives guidance on the type of pro
37、perty that is appropriate for some common engineered wood products. NOTE 2 Where component properties are reported, they are in general specific to a given size of product. Different sized products will have different component properties. Determination of the characteristic values for structural pr
38、operties shall be in accordance with ISO 12122-1 unless specifically specified in the reference product standard. 9.2 Characteristic values of material properties 9.2.1 Characteristic modulus of elasticity and shear modulus The characteristic modulus of elasticity and shear modulus shall be the mean
39、 value, taken as the average of the test values evaluated in accordance with ISO 12122-1. ISO 2017 All rights reserved 3 ISO 12122-4:2017(E) 9.2.2 Characteristic bearing strength The characteristic values for bearing strength, both parallel and perpendicular to grain, shall be the mean property obta
40、ined from results of tests. 9.2.3 Other characteristic values for strength based on the 5th percentile test value The 75 % lower single-sided confidence limit of the test 5th percentile value shall be evaluated. Suitable methods for evaluating the 5th percentile value of the test data and estimating
41、 the 75 % lower single- sided confidence limit are presented in ISO 12122-1. 9.3 Characteristic values of component properties 9.3.1 Characteristic stiffness The characteristic stiffness shall be the mean value, taken as the average of the test values evaluated in accordance with ISO 12122-1. 9.3.2
42、Characteristic bearing strength The characteristic values for bearing strength evaluated in accordance with 9.2.2, both parallel and perpendicular to grain, shall be the mean property obtained from results of tests. NOTE Even though other properties are component properties, bearing strengths are ge
43、nerally reported as material properties. Further guidance is given in Annex A. 9.3.3 Other characteristic capacities for strength based on the 5th percentile test value The 75 % lower single-sided confidence limit of the test 5th percentile value shall be evaluated. Suitable methods for evaluating t
44、he 5th percentile value of the test data and estimating the 75 % lower single- sided confidence limit are presented in ISO 12122-1. 10 Report The report shall comply with the requirements of ISO 12122-1.4 ISO 2017 All rights reserved ISO 12122-4:2017(E) Annex A (informative) Commentary A.1 Commentar
45、y on scope This document presents methods for determining characteristic values for engineered wood products. It is to be used in conjunction with ISO 12122-1. This document presents a uniform methodology for the evaluation of characteristic values that are consistent with the characteristic values
46、found for other structural timber products. This document does not establish methods for the determination of design values, which may be determined based on characteristic values from test data by incorporating safety factors to account for any or all of the following factors. Expected changes in p
47、roduct or product properties over a long period. These changes could be due to variations in timber resource quality, production methods or changes in other raw materials. The complexity of the reference population. For example, where the reference population has a large number of producers who draw
48、 their resources over a large area or use different production parameters, then the sampling may not effectively reflect all possible combinations of resource quality and production methods. In this way, the sample may not be truly representative and a safety factor may be applied to allow for that.
49、 Variations in time of the assembly used for the engineered wood product. These variations may include end-joint treatment of elements, element specification, curing and holding times. Anticipated variations in quality control across the reference population in the future. Characteristic values presented in this document relate only to the determination of characteristic values from the results of tests on full-scale engineered wood products. The ISO 12122- series has this common basis. However, in many cases, the char
