1、CEN EN*32b-L 94 3404589 00b3765 898 EUROPEAN STANDARD EN 326-1 NORME EUROPENNE EUROPISCHE NORM February 1994 UDC 674.03 : 674.815 : 620.113 Descriptors: Wooden boards, sampling, test specimens, cutting, test results English version Wood-based panels - Sampling, cutting and inspection - Part 1: Sampl
2、ing and cutting of test pieces and expression of test results Panneaux base de bois - Echantilonnage, dcoupe et contrle - Partie 1: Echantillonnage et dcoupe des prouvettes expression des rsultats dessai Prfergebnisse Holzwerkstoffe - Probenahme, Zuschnitt und berwachung - Teil 1: Probenahme und Zus
3、chnitt der Prfkrper sowie Angabe der This European Standard was approved by CEN on 1994-02-07. CEN memberc are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-dat
4、e lists and bibliographical references concerning such national standards may be 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 translation under the
5、responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, N
6、orway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Centrai Secretariat: rue de Stassart 36, B-1050 Brussels O 1994 Copyright reserved to CEN members Ref. No. EN 326-1 : 1994 E CEN EN
7、a326-11 74 3404589 00611766 724 Page 2 EN 326-1 : 1994 Foreword Contents This European Standard has been prepared by CENIE 112, Woodbased panels, the secretariat of which is held by DIN. It was submitted to Formal Vote and the result was positive. This European Standard shall be given the status of
8、a National Standard, either by publication of an identical text or by endorsement, at the latest by August 1994, and conflicting national standards shall be withdrawn at the latest by December 1994. According to the CENiCENELEC Internal Regulations, the following countries are bound to implement thi
9、s European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Foreword 1 Scope 2 Normative references 3 Symbols 4 Definitions 5 Sampling 6 Test pieces 7 Expression o
10、f test results 8 %st report Annex A (informative) Example for a cutting plan for plywood bonding quality tests Annex B (informative) Bibliography CEN EN*326-3 74 I 3404589 0063767 660 1 Scope This European Standard specifies certain rules for the sampling and cutting of test pieces and the expressio
11、n and presentation of test results, in order to obtain information on the properties of wood-based panels. NOTE. This standard does not cover the sampling and cutting of test pieces for the derivation of characteristic values for structural design. These tests have to be carried out on medium-sized
12、test pieces according to the rules given in EN 789 using the minimum number of panels to be sampled according to EN 384. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropria
13、te places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard, only when incorporated in it by amendment or revision. For undated references the latest edition of the publicati
14、on referred to applies. EN 322 Wood-ked panels EN 323 Wood-ked panels Determination of moisture content Determination of density 3 Symbols 3.1 Letter symbols m Number of test pieces cut from each single panel of the sample, in each direction n Number of panels taken as sample = size of the sample N
15、Number of panels in one inspection lot = inspection lot size Lqb x, Lower and upper 5 5% quantile values of WF, y, the sample, respectively S Estimate of the standard deviation calculated from test values or measurements Page 3 EN 326-1 : 1994 Estimate of the variance calculated from test values or
16、measurements Estimate of the variance within a panel j of the sample Estimate of the standard deviation between panel means Estimate of the variance between panel means Estimate of the mean variance within panels Single-sided 5 %-t-value of a normally distributed sample of n panels xu, xukl Single t
17、est value or measurement Xj, Xjk Mean value (arithmetic mean) of the m single test values (or measurements) or of a group k and/or I of test values (or measurements), obtained from a single panel j Grand mean; mean value (arithmetic mean) of ail mn test values (or measurements) or of a group k and/o
18、r 1 of test values (or measurements), obtained from a sample _ X, 3.2 Indices i Serial test piece number within a panel (i = 1, 2, ., m) j kst panel identification number within a sample(j = 1, 2, ., n) k, E Marks identifying the grouping of test pieces with regard to the direction in the plane of t
19、he panel and to their surfaces, respectively w Property within a panel L Lower specification limit U Upper specification limit CEN EN*32b-L 9Y II 3VOY589 00bL7b8 5T7 EN 314-2 Page 4 EN 326-1 : 1994 10 i 4 Definitions For the purpose of this standard, the following definitions apply: Drawn at random:
20、 Sampling of panels in such a way that each panel of the inspection lot has an equal chance of being selected, and cutting of test pieces from a single panel in such a way that each part of the panel has an equal chance of being selected as a t,est, piece. Inspection lot: A proportion of production,
21、 which is presented at a given time for sampling and inspection, consisting of panels of the same type within the same thickness range and coming from the same production line. Inspection lot size: Number of panels in one inspection lot. Quality characteristic: A property that is essential for the j
22、udgement of a product in accordance with a relevant EN specification. Sample: A collection of panels which are drawn from an inspection lot. Unless otherwise agreed, the panels of the sample are drawn at random. Measurement: The value of a specific quality characteristic obtained eit.her from a test
23、 piece or from a direct measurement. Test piece: A piece of panel cut to the size required for testing a specific property. Test value: The value of a specific quality characteristic obtained from a test piece. Variable: A test value or measurement which can be measured on a continuous scale. 5 Samp
24、ling 5.1 Sampling of panels The size of the sample ?z depends on the purpose of the determination of panel properties. Detailed information on the size of the sample for quality control in the factory is given in EN 326-2, and for the inspection of the performance of a consignment of panels in EN 32
25、6-3. Alternatively, the sample size may be specified in the relevant EN specification. 5.2 Sampling of test pieces Due to the variability both within and between panels, it is necessary to test a certain number of panels n as well as a certain number of test pieces rn, cut from a single panel, in or
26、der to obtain reliable results. Examples of the minimum number of test pieces rr? are given in table 1, for other panel properties rn shall be as laid down in the relevant EN for the respective test method. Table 1. Minimum number m of small test pieces cut from each single panel I Panel property Mo
27、isture content Dimensional movement Density Modulus of elasticity in bending and bending strength Internal bond Swelling in thickness after immersion in water Surface soundness Plywood bonding quality EN 322 l.2 EX 318 I EN 319 I8 EX 317 , I EN 311 I For the determination of those properties which d
28、iffer in the two principal directions of the plane of the panel, two groups of m test pieces shall be cut from each panel. One group shall have its longitudinal axis parallel to the direction of the production (or the length of the panel), the other shall have its longitudinal axis perpendicular to
29、this direction. In testing the bonding quality of plywood, relates to a pair of glue lines and to each pretreatment (see annex A). CEN EN*32b-1 94 .II 3404589 b2769 433 6 Test pieces 6.1 The test pieces shall be cut from the individual panels to the dimensions specified in the relevant standards of
30、test methods, using a suitable method to ensure unbiased selection. At least one test piece of each group of test pieces shall be cut from the edge of the trimmed panel after any edge profiling and/or protective treatment has been removed. 6.2 An example of a cutting plan for small test pieces is gi
31、ven in figure 1. Except for plywood bonding quality tests, for which a cutting plan is given in annex A, the minimum distance between two test pieces for the same test shall be 100 mm. This requirement may be waived if replacement test pieces are required. 6.3 All test pieces cut from a panel shall
32、be marked on the same surface with: - the test panel identification number; - the test piece serial number; - and if possible, the original length direction and the original upper or lower surface of the panel. 6.4 For panels which are asymmetric about the centre of their thickness, so that the test
33、 result is influenced by which surface is uppermost when tested (e.g bending strength), half of the total number of test pieces m (i.e. m/2) shall be tested in each surface orientation. In all other cases where the orientation of the surface of the panel is of minor influence on the property tested,
34、 the position of the upper or lower surface during the test shall be chosen at random. 6.5 Cutting of test pieces shall be carried out in such a way that their edges are clean, without burns, and perpendicular to the plane of the panel. 7 Expression of test results 7.1 Each specific property of each
35、 panel of the sample shall be determined as specified in the relevant EN using either test pieces or measurements taken from whole panels. 7.2 The test results of each individual test piece, from each panel of the sample, shall be reported. Page 5 EN 326-1 : 1994 7.3 With the exception of testing th
36、e bonding quality of plywood1), further evaluation of the test results of the sample (either for inspection procedures or for internal as well as external production control) shall be made using the following calculations: 7.3.1 Mean value of each individual panel (panel mean) For each group of test
37、 pieces (or measurements, respectively) calculate the mean value Xj of each individual panel according to: ti Xj = xum (1) i= 1 7.3.2 Variance within each panel For each group of test pieces (or measurements, respectively) calculate the variance s, j2 within each panel according to: )I s, p = (qj -
38、q)z/ (m i) (2) ,= 1 7.3.3 Grand mean (mean of panel means) Calculate the grand mean x of all test values, or of a group of test values, from the sample according to: , ,I - 5 = xu/(mn) = , of a panel property according to: and the upper 5 %-quantile u4; y(, respectively: - LS, 2, = x - tn (Ga) us5%
39、=x+ tn5x (6b) - I For testing the shear strength of glue lines in plywood the mean value of each pair of glue lines for each panel has to be calculated according to 7.3.1. Page 6 EN 326-1 : 1994 NCrrE. For properties which are independent from orientation (e.g. D, I and Q) one test piece shall be ta
40、ken from an outer edne of a trimmed a) *st Test piece number Density DI to D6 a) i Bending t l to B1Z t B5= I I t j L .- Dimensions in millimetres Orientation of the lontudinal axis of the test piece parallel tJ the length of a plywood panel or to the machine direction of other panel types Onentatio
41、n of the IonBtudinal axis of the test piere perpendicular to the length of a plywood panel or to the machine direction of other panel types (=) I a) Outer edge tnmmed panel where this can be identifGd Figure 1. Example of a cutting plan for small test pieces for determination of certain properties (
42、thickness of the panel about 20 mm) CEN ENx32b-L 94 3404589 00bL77L O91 Page 7 EN 326-1 : 1994 able 2. Single-sided t-values in relation to the sample size n Sample size n 18 I10 115 I20 I25 I30 135 140 I 60 I100 8 Test report 8.1 Mandatory information Each report on sampling and cutting of test pie
43、ces and expression of test results shall contain: 8.1.1 Name of the testing institute 8.1.2 Description of the inspection lot 8.1.2.1 Name of the supplier (or his representative) 8.1.2.2 Place and date of sampling and persons present at sampling 8.1.2.3 General condition of the inspection lot 8.1.2.
44、4 Type, kind, and characteristics of the panels as specified in the relevant EN 8.1.2.5 Density according to EN 323 8.1.2.6 Moisture content at the time of testing according to EN 322 8.1.2.7 Nominal dimensions of the panels 8.1.2.8 Inspection lot size 8.1.3 Description of the sample 8.1.3.1 Sample
45、size - number of panels n - number of test pieces taken from each panel for each group of test pieces m 8.1.3.2 A copy of the cutting plan used 8.1.4 Expression of the test results of each property investigated in accordance with the relevant EN 8.1.4.1 Mean value of each panel xj 8.1.4.2 Grand mean
46、 2 8.1.4.3 Mean standard deviation within panels S, 8.1.4.4 Standard deviation between panel means 8.1.5 Any deviation from this EN and from relevant EN test methods as well as any information which may be of importance with regard to testing. 8.2 Additional, non-mandatory information In addition th
47、e test report may contain the following non-mandatory information: 8.2.1 Additional description of the inspection lot, time of manufacture of the panels, if known 8.2.2 Additional description of the sample, description of any identification mark according to 6.4 8.2.3 Additional information on test
48、results 8.2.3.1 All single test results qj 8.2.3.2 The lower or upper 5 %-quantile (L(k y, or Us5 y, respectively) 8.2.4 Any further relevant information CEN EN+32b-L 94 I 3404589 O063772 T28 H Page 8 EN 326-1 : 1994 Annex A (informative) Example of a cutting plan for the plywood bonding quality tes
49、t I *&2 3 Dimensions in millimetres b width a) Pair of blocks - _ indicates the fibre direction of Le outer veneers Centre blocks (random distance from the middle of the panel) Edge blocks 1 -C Number of pairs of blocks X c For each pretreatment and each pair of glue lines separate test pieces are required. Wst piece T6 (and possibly T7 and more) is a spare test piece.
