BS EN 310-1993

BRITISH STANDARD

Wood-based panels — Determination of modulus of elasticity in bending and of bending strength

The European Standard EN 310:1993 has the status of a British Standard

UDC 674.03:620.172.225:620.174

BS EN 310:1993

BS EN 310:1993

Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries. Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom

This British Standard, having been prepared under the direction of the Technical Sector Board for Building and Civil Engineering (B/-), was published under the authority of the Standards Board and comes into effect on 15 April 1993 © BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference B/541 Draft for comment 90/15587 DC ISBN 0 580 21056 1

Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standardiseringsraad Suomen Standardisoimisliito, r.y. Association française de normalisation Deutsches Institut für Normung e.V. Hellenic Organization for Standardization Technological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-instituut Norges Standardiseringsforbund Instituto Portuguès da Qualidade Asociación Española de Normalización y Certificación Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution

Amendments issued since publication Amd. No.

Date

Comments

BS EN 310:1993

Contents Cooperating organizations National foreword Foreword Text of EN 310 National annex NA (informative) Committees responsible National annex NB (informative) Cross-reference

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Page Inside front cover ii 2 3 Inside back cover Inside back cover

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BS EN 310:1993

National foreword This British Standard has been prepared under the direction of the Technical Sector Board for Building and Civil Engineering and is the English language version of EN 310:1993 Wood-based panels — Determination of modulus of elasticity in bending and of bending strength, published by the European Committee for Standardization (CEN). EN 310 was produced as a result of international discussion in which the UK took an active part. The principle of this method is technically equivalent to A.10 and A.12 of BS 1142:1989 Specification for fibre building boards and to clauses 10 and 11.1 of BS 5669 Particleboard — Part 1:1989 Methods of sampling, conditioning and test, both of which will be withdrawn in due course. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.

Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. ii

© BSI 03-1999

EUROPEAN STANDARD

EN 310

NORME EUROPÉENNE February 1993

EUROPÄISCHE NORM UDC 674.03:620.172.225:620.174

Descriptors: Wood-based panel, particleboard, plywood, fibreboard, OSB, cement-bonded particleboard, test method, modulus of elasticity, bending strength

English version

Wood-based panels — Determination of modulus of elasticity in bending and of bending strength

Panneaux à base de bois — Détermination du module d’élasticité en flexion et de la résistance à la flexion

Holzwerkstoffe — Bestimmung des Elastizitätsmoduls und der Biegefestigkeit

This European Standard was approved by CEN on 1992-12-15. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date 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 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, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

CEN European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels © 1993 Copyright reserved to CEN members

Ref. No. EN 310:1993 E

EN 310:1993

Foreword This European Standard was prepared by Working Group 4 “Common test methods” (Secretariat: United Kingdom) of Technical Committee CEN/TC 112 “Wood-based panels” (Secretariat: Germany). The text is based on ISO 9429 (at present ISO/DIS) which has been elaborated with European participation. This standard is one of a series of standards specifying methods of test for determining dimensions and properties of wood-based panels. No existing European Standard is superseded. 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 August 1993, and conflicting national standards shall be withdrawn at the latest by December 1994. In accordance with the CEN/CENELEC Internal Regulations the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom.

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Contents 1 Scope 2 Normative references 3 Principle 4 Apparatus 5 Test pieces 6 Procedure 7 Expression of results 8 Test report Annex A (informative) Bibliography Figure 1 — Arrangement of the binding apparatus Figure 2 — Cross section of tubular boards Figure 3 — Load-deflection curve within the range of elastic deformation

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EN 310:1993

1 Scope This European Standard specifies a method of determining the apparent modulus of elasticity in flatwise bending and bending strength of wood-based panels of nominal thickness equal to or greater than 3 mm.

4.2.2 A suitable instrument capable of measuring the deflection of the test piece in the middle of the span with an accuracy of 0,1 mm. 4.2.3 A suitable load measurement system capable of measuring the load applied to the test piece with an accuracy of 1 % of the measured value.

NOTE Structural design values shall be determined according to methods according to EN 789.

5 Test pieces

2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate 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 publication referred to applies. EN 325, Wood-based panels — Determination of dimensions of test pieces. EN 326-1, Wood-based panels — Sampling, cutting and inspection — Part 1: Sampling and cutting of test pieces and expression of test results1).

3 Principle The modulus of elasticity in bending and bending strength are determined by applying a load to the centre of a test piece supported at two points. The modulus of elasticity is calculated by using the slope of the linear region of the load-deflection curve; the value calculated is the apparent modulus, not the true modulus, because the test method includes shear as well as bending. The bending strength of each test piece is calculated by determining the ratio of the bending moment M, at the maximum load Fmax, to the moment of its full cross section.

4 Apparatus 4.1 Measuring instruments, as specified in EN 325. 4.2 Testing apparatus (Figure 1), having the following essential components. 4.2.1 Two parallel, cylindrical, roller-bearing supports of length exceeding the width of the test piece and of (15 ± 0,5) mm diameter. The distance between the supports shall be adjustable. A cylindrical loading head, of the same length and (30 ± 0,5) mm in diameter, placed parallel to the supports and equidistant from them.

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5.1 Sampling and cutting Sampling and cutting of the test pieces shall be carried out according to EN 326-1. Series of both transverse and longitudinal test pieces are required. 5.2 Dimensions of test pieces The test pieces shall be rectangular, and of the following dimensions: The width b shall be (50 ± 1) mm. In the case of extruded panels, cellular panels, or panels of similar structure with cavities parallel to the length of the test piece, the width of the test piece shall be at least twice the width of an individual core element (e.g. two tube diameters plus two web thicknesses) and the test pieces shall have a symmetrical cross-sectional area as shown in Figure 2. In test pieces with cavities perpendicular to the length, the loading head shall be located directly above a web. The length l2 shall be 20 times the nominal thickness plus 50 mm, with a maximum length of 1 050 mm and a minimum length of 150 mm. If the deflection of the test piece is large but rupture (failure) does not occur, the distance between supports shall be reduced for testing the bending strength. The test report shall include the distance between supports at which failing tests were conducted. If this procedure needs to be adopted, a new set of test pieces shall be used. Plywood test pieces shall be free of visible strength-reducing characteristics. 5.3 Conditioning The test pieces shall be conditioned to constant mass in an atmosphere with a relative humidity of (65 ± 5) % and a temperature of (20 ± 2) °C. Constant mass is considered to be reached when the results of two successive weighing operations, carried out at an interval of 24 h, do not differ by more than 0,1 % of the mass of the test piece.

At present at the draft stage.

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EN 310:1993

Figure 1 — Arrangement of the bending apparatus

Figure 2 — Cross section of tubular boards

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EN 310:1993

6 Procedure 6.1 Measure the width and thickness of each test piece according to EN 325 at the following points: — the thickness at the intersection of the diagonals; — the width at the mid-length. 6.2 Adjust the distance between the centres of the supports, to within 1 mm of 20 times the nominal thickness of the panel, but not less than 100 mm and not more than 1 000 mm. Measure the distance between the centres of the supports to the nearest 0,5 mm. 6.3 Place the test piece flat on the supports, with its longitudinal axis at right angles to those of the supports with the centre point under the load (Figure 1). 6.4 The load shall be applied at a constant rate of cross-head movement throughout the test. The rate of loading shall be adjusted so that the maximum load is reached within (60 ± 30) s. Measure the deflection in the middle of the test piece (below the loading head) to an accuracy of 0,1 mm and plot these values against the corresponding loads measured to an accuracy of 1 % of the measured value. If deflection is determined by incremental readings, at least 6 pairs of readings shall be used. 6.5 Record the maximum load to an accuracy of 1 % of the measured value. 6.6 Carry out tests on two groups of test pieces according to the two directions of the board, i.e. in the longitudinal and transverse directions. Within each group, test half of the test pieces with the “top face” upwards and half with the “bottom face” upwards.

7 Expression of results 7.1 Modulus of elasticity 7.1.1 The modulus of elasticity Em (in N/mm2), of each test piece, is calculated from the formula: 3

l1 ( F2 – F1 ) E m = -----------------------------------------3 4 bt ( a 2 – a 1 )

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where l1 is the distance between the centres of the supports, in millimetres b is the width of the test piece, in millimetres t is the thickness of the test piece, in millimetres F2 – F1 is the increment of load on the straight line portion of the load-deflection curve, (Figure 3) in N. F1 shall be approximately 10 % and F2 shall be approximately 40 % of the maximum load a2 – a1 is the increment of deflection at the mid-length of the test piece (corresponding to F2 – F1) The modulus of elasticity for each test piece shall be expressed to three significant figures. 7.1.2 The modulus of elasticity for each group of test pieces taken from the same board (6.6) is the arithmetic mean of the moduli of elasticity of the appropriate test pieces, expressed to three significant figures. 7.2 Bending strength 7.2.1 The bending strength fm (in N/mm2), of each test piece, is calculated from the formula: 3 F max l 1 f m = ------------------------2 2 bt where Fmax is the maximum load, in newtons l1, b, and t are in millimetres as defined in 7.1.1 The bending strength of each test piece shall be expressed to three significant figures. 7.2.2 The bending strength for each group of test pieces taken from the same board (6.6) is the arithmetic mean of the bending strengths of the appropriate test pieces, expressed to three significant figures.

8 Test report As described in EN 326-1.

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EN 310:1993

Figure 3 — Load-deflection curve within the range of elastic deformation

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EN 310:1993

Annex A (informative) Bibliography EN 789, Timber structures — Testing of wood-based panels for the determination of mechanical properties for structural purposes2). ISO 9429:1987, Wood-based panels — Determination of apparent modulus of elasticity in bending and of bending strength.

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At present at the draft stage.

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BS EN 310:1993 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted by the Technical Sector Board for Building and Civil Engineering (B/-) to Technical Committee B/541, upon which the following bodies were represented: American Plywood Association Association of British Plywood and Veneer Manufacturers British Woodworking Federation Chartered Institute of Building Coordinator for Timber and Timber Products Council of the Forest Industries of British Columbia Department of the Environment (Timber Division, Building Research Establishment) Fibre Building Board Organisation (FIDOR) Finnish Plywood International Flat Roofing Contractors’ Advisory Board Forestry Commission Furniture Industry Research Association Institution of Structural Engineers National Federation of Roofing Contractors National House-building Council National Panel Products Association Royal Institute of British Architects Timber Research and Development Association Timber Trade Federation United Kingdom and Ireland Particleboard Association Coopted member

National annex NB (informative) Cross-reference Publication referred to

Corresponding British Standard

EN 325:1993

BS EN 325:1993 Wood-based panels — Determination of dimensions of test pieces

© BSI 03-1999

BS EN 310:1993

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