Bsi bs en 00538 1994 (1999)

00346232 PDF BRITISH STANDARD BS EN 538 1994 Clay roofing tiles for discontinuous laying — Flexural strength test The European Standard EN 538 1994 has the status of a British Standard UDC 691 424 666[.]

BRITISH STANDARD BS EN

538:1994

Clay roofing tiles for

discontinuous laying —

Flexural strength test

The European Standard EN 538:1994 has the status of a

British Standard

UDC 691.424.666.74:620.17

This British Standard, having

been prepared under the

direction of Technical Committee

B/542, was published under

the authority of the Standards

Board and comes

into effect on

15 December 1994

© BSI 08-1999

The following BSI references

relate to the work on this

standard:

Committee reference B/542/3

Draft for comment 91/16433 DC

ISBN 0 580 23104 6

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:

Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland

Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut

Spain Asociación Española de Normalización y Certificación

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

BS EN 538:1994

Contents

Page

National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back cover

ii © BSI 08-1999

National foreword

This British Standard has been prepared under the direction of Technical Committee B/542, Roofing and cladding products for discontinuous laying, and is

the English language version of EN 538:1994, Clay roofing tiles for discontinuous

laying — Flexural strength test, published by the European Committee for

Standardization (CEN)

EN 538 partially replaces BS 402:1990, which will be withdrawn in due course

EN 538 was produced as a result of international discussions in which the UK took an active part

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

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 538

May 1994

UDC 691.424.666.74:620.17

Descriptors: Ceramics, roofing tiles, determination, flexural strength, break strength

English version

Clay roofing tiles for discontinuous laying —

Flexural strength test

Tuiles de terre cuite pour pose en discontinu —

Détermination de la résistance à la rupture par

flexion

Tondachziegel für überlappende Verlegung — Prüfung der Biegetragfähigkeit

This European Standard was approved by CEN on 1994-05-18 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

© 1994 Copyright reserved to CEN members

Ref No EN 538:1994 E

© BSI 08-1999

2

Foreword

This European Standard has been prepared by

CEN/TC 128, Roof covering products for

discontinuous laying, the Secretariat of which is

held by ON

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

November 1994, and conflicting national standards

shall be withdrawn at the latest by November 1994

According to 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

Contents

Page

7.2 Tiles with sidelock and headlock,

tiles with sidelock only, and

7.3.2 Tiles with nib(s) with or without

Figure 3 — Test method for interlocking tiles 5 Figure 4.1 — Test with contoured

Figure 4.2 — Test with contoured hardwood shim (variation for tiles with no flat area) 6 Figure 5.1 — Test with moulded plaster shim 6 Figure 5.2 — Test with moulded plaster

Figure 6 — Test on over and under tiles

Figure 7 — Test for over and under tiles with nibs not resting on one generatrix 8 Figure 8 — Test for over and under tiles

with nibs resting on one generatrix only 8

EN 538:1994

1 Scope

This European Standard describes the test method

used to evaluate the flexural strength of clay roofing

tiles as defined in the standard EN 1304 Clay

roofing tiles — Product definitions and

specifications.

Other physical characteristics are dealt with by the

standard EN 539 Clay roofing tiles —

Determination of physical

characteristics: Impermeability and frost resistance.

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 1304, Clay roofing tiles — Product definitions

and specifications1)

EN 539, Clay roofing tiles — Determination of

physical characteristics

EN 539-1, Impermeability test

EN 539-2, Frost tests1)

ISO 48:1979, Vulcanized rubbers — Determination

of hardness (Hardness between 30 and 85 IRHD)

3 Symbols and abbreviations

4 Test principle

Verification of the ability of the product to resist a

centred load when subjected to flexion on two simple

bearers

5 Samples

The evaluation of flexural strength is made on ten samples each one consisting of a whole tile dried in ambient air If the tiles have been subjected to humidity, they shall be dried in a laboratory atmosphere before testing (temperature + 10 °C and + 40 °C, relative humidity less than 90 %)

6 Apparatus

The apparatus consists of:

— a device that applies a load with an accuracy

of 2 % and a load increase rate of 0.05 kN/s;

— a system used as lower bearers and, depending

on the type of tile, either made up of rods or half-rods, one of which is articulated in order to rotate in a vertical plane and obtain as uniform a load distribution as possible on the sample, or for some over and under tiles by a flat plate

supporting the tile;

— a round steel bar fitted to the bottom of the

load application device The upper and lower bearers shall have a radius of between 15 mm and 20 mm and a length greater than the width

of the tile to be tested;

— a set of hardwood shims used for chocking the

lower bearers as defined in 7.2;

— a hardwood shim adapted to the shape of the

tile as defined in 7.2, should this chocking system

be preferred to the plaster shim type;

For apparatus where the weight of the tile and fittings is taken into account when reading the load, the corresponding tare is not included in the failure load value

7 Test procedure

7.1 Plain tiles

Place the tile on the two lower bearers (see Figure 2)

so that:

— the first bearer is in the position normally occupied by the batten;

— the second bearer is separated from the first by

a distance equal to two thirds of the overall

length (L) of the tile.

Place this assembly in such a position that the load application bar is parallel to the two lower bearers and equidistant from both

Note the distance between the bearer axes

Apply the test load progressively at a rate of not more than 0,05 kN/s until the sample fails

1) In preparation.

L Overall length of tile

F Load at failure

Figure 1 — Test principle

4 © BSI 08-1999

Note the value (F) of the load at failure, expressed

in kN and rounded off to two decimal points

7.2 Tiles with sidelock and headlock, tiles with

sidelock only and overlapping tiles

Place the tile on the two lower bearers in the same

horizontal plane (see Figure 3) so that:

— the first bearer is in the position normally

occupied by the batten;

— the second bearer is separated from the first by

a distance equal to two-thirds of the overall

length (L) of the tile.

In order to ensure that the tile remains in a stable

position, use wooden shims of the same width as the

upper shim to support the tile on the lower bearers,

and a shim adapted to fit the shape of the tile for the

upper bearer

This upper support can be obtained either by using

a contoured hardwood shim (Figure 4.1 and

Figure 4.2) or a moulded plaster one (Figure 5.1

and Figure 5.2) to keep the load application bar

horizontal

The contoured piece of wood has a strip of rubber on

the part in contact with the tile This 5 mm-thick

strip shall have a specified IRHD hardness 50 ± 5,

measured as per ISO 48:1979 The width of the

contoured hardwood shim or moulded plaster shim

shall be equal to the diameter of the load application

bar

Place the assembly in such a position that the load application bar is parallel to the two lower bearers and equidistant from both

Note the distance between the bearer axes

Apply the load progressively at a rate of 0,05 kN/s until the sample fails

Note the value (F) of the load at failure, expressed

in kN, and rounded off to the nearest two decimal points

7.3 Over and under tiles 7.3.1 Tiles without nibs

Place the tile, with its concavity facing downward in

a horizontal position, on the plate of the apparatus

so that the load application bar is in contact with the tile’s upper generatrix and the bar’s horizontal pin

is approximately halfway between the two ends of the tile (see Figure 6)

Apply the load progressively at a rate of approximately 0,05 kN/s until the sample fails

Note the value (F) of the load at failure, expressed

in kN and rounded off to the nearest two decimal points

Determine the average load at failure as the arithmetical mean of ten readings expressed in kN and rounded off to two decimal points

7.3.2 Tiles with nib(s) with or without flat bottom

Place the tile on the two lower bearers (see Figure 7 and Figure 8) so that:

— the first bearer is in the position normally occupied by the batten;

— the second bearer is separated from the first by

a distance equal to two-thirds of the overall

length (L) of the tile.

In the case of tiles that lie only on one generatrix, hold the sample in place by using shims at one end (see diagram for method, Figure 8)

Place the assembly in such a position that the load application bar is parallel to the two lower bearers and equidistant from both

Note the distance between the bearer axes

Apply the load progressively at a rate of approximatively 0,05 kN/s until the sample fails

Note the value (F) of the load at failure, expressed

in kN and rounded off to the nearest two decimal points

Determine the average load at failure as the arithmetical mean of ten readings expressed in kN and rounded off to the nearest two decimal points

Figure 2 — Test for plain tiles

EN 538:1994

Figure 3 — Test method for interlocking tiles

Figure 4.1 — Test with contoured hardwood shim

6 © BSI 08-1999

Figure 4.2 — Test with contoured hardwood shim (variation for tiles with no flat area)

Figure 5.1 — Test with moulded plaster shim

EN 538:1994

Figure 5.2 — Test with moulded plaster shim (variation)

Figure 6 — Test on over and under tiles without nibs

8 © BSI 08-1999

8 Test report

The test report shall specify:

— the European standard number, EN 538;

— the name of the test laboratory;

— the date on which the laboratory received the sample;

— the test date;

— a description and identification of the tile, including the type, the length and the width, the manufacturer’s name and, where possible, the production date;

— the distance between the centres of the lower bearers, except for over and under tiles without nibs;

— the load at failure for each tile, expressed to the nearest 0.01 kN;

— the minimum load registered at failure;

— the mean load at failure;

— comments if necessary;

— signature of the person responsible for the test

NOTE A tile’s flexural strength depends on its shape Consequently, the values indicated in the report cannot be compared directly from one type of tile to another.

Figure 7 — Test for over and under tiles with

nibs not resting on one generatrix

Figure 8 — Test for over and under tiles with

nibs resting on one generatrix only

BS EN 538:1994

© BSI 08-1999

National annex NA (informative)

Committees responsible

The United Kingdom participation in the preparation of this European Standard was entrusted by Technical Committee B/542, Roofing and cladding products for discontinuous laying, to Subcommittee B/542/3, Clay roofing tiles, upon which the following bodies were represented:

Clay Roofing Tile Council

Department of the Environment (Building Research Establishment)

National Clayware Federation

National Federation of Roofing Contractors

National House-building Council

Royal Institution of British Architects

National annex NB (informative)

Cross-references

Publication referred to Corresponding British Standard

BS EN 539 Clay roofing tiles for discontinuous laying — Determination of physical

characteristics

EN 539-1:1994 Part 1:1994 Impermeability test

ISO 48:1979 BS 903 Physical testing of rubber

Part A26:1969 Determination of hardness

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