BRITISH STANDARD BS EN 727:1995BS 2782-11:Method 1103V:1995

Plastics piping and ducting systems — Thermoplastics pipes and fittings — Determination of Vicat softening temperature (VST)

The European Standard EN 727:1994 has the status of a British Standard

UDC 621.643.06:621.642.2-036.073:620.1:536.421.2

BS EN 727:1995

This British Standard, having been prepared under the direction of the Materials and Chemicals Sector Board, was published under the authority of the Standards Board and comes into effect on15 June 1995

© BSI 08-1999

The following BSI references relate to the work on this standard:Committee reference PRI/61Draft for comment 92/41378 DC

ISBN 0 580 23986 1

Committees responsible for this British Standard

The preparation of this British Standard was entrusted to Technical Committee PRI/61, Plastic piping systems and components, upon which the following bodies were represented:

British Gas plcBritish Plastics FederationBritish Plumbing Fittings Manufacturers’ AssociationBritish Valve and Actuator Manufacturers’ AssociationDepartment of the Environment (British Board of Agrément)Department of the Environment (Building Research Establishment)Department of the Environment (Property and Buildings Directorate)Department of TransportElectricity AssociationFederation of Civil Engineering ContractorsHealth and Safety ExecutiveInstitute of Building ControlInstitute of MaterialsInstitution of Civil EngineersInstitution of Gas EngineersInstitution of Water and Environmental ManagementNational Association of Plumbing, Heating and Mechanical Services

ContractorsPipeline Industries GuildPlastics Land Drainage Manufacturers’ AssocociationSociety of British Gas IndustriesSociety of British Water IndustriesWater Companies AssociationWater Services Association of England and Wales

The following bodies were also represented in the drafting of the standard, through subcommittees and panels:

ERA Technology Ltd.Engineering Equipment and Materials Users AssociationRAPRA Technology Ltd.

Amendments issued since publication

Amd. No. Date Comments

BS EN 727:1995

© BSI 08-1999 i

Contents

PageCommittees responsible Inside front coverNational foreword iiForeword 21 Scope 32 Normative references 33 Principle 34 Apparatus 35 Test pieces 36 Conditioning 47 Procedure 48 Test report 5Figure 1 — Schematic diagram of apparatus for the determination of the Vicat softening temperature 4List of references Inside back cover

BS EN 727:1995

ii © BSI 08-1999

National foreword

This British Standard has been prepared under the direction of Technical Committee PRI/61, and is the English language version of EN 727:1994 Plastics piping and ducting systems — Thermoplastics pipes and fittings — Determination of Vicat softening temperature (VST), published by the European Committee for Standardization (CEN).It is incorporated into BS 2782 Methods of testing plastics — Part 11: Thermoplastics pipes, fittings and valves, as Method 1103V:1995, for association with related test methods for plastics materials and plastics piping components.This test method has been prepared for reference by other standards under preparation by CEN for specification of plastics piping systems and components. It has been implemented to enable experience of the method to be gained and for use for other fresh applications.It is also for use for the revision or amendment of other national standards as practicable, but it should not be presumed to apply to any existing standard or specification which contains or makes reference to a different test method until that standard/specification has been amended or revised to make reference to this method and adjust any requirements as appropriate.

WARNING. This British Standard, which is the English language version of EN 727:1994, does not necessarily detail all the precautions necessary to meet the requirements of the Health and Safety at Work etc. Act 1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel.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.

Cross-reference

International Standard Corresponding British Standard

ISO 306:1987 BS 2782 Methods of testing plasticsPart 1. Thermal propertiesMethods 120A, 120B, 120D and 120E:1990 Determination of Vicat softening temperature of thermoplastics

Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, 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.

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EUROPEAN STANDARD

NORNE EUROPÉENNE

EUROPÄISCHE NORM

EN 727

August 1994

UDC 621.643.06:621.642.2-036.073:620.1:536.421.2

Descriptors: Plastic tubes, thermoplastic resins, pipe fittings, softening tests, softening point

English version

Plastics piping and ducting systems — Thermoplastics pipes and fittings —

Determination of Vicat softening temperature (VST)

Systèmes de canalisations et de gaines plastiques — Tubes et raccords thermoplastiques — Détermination de la température de ramollissement Vicat (VST)

Kunststoff-Rohrleitungs- und Schutzrohrsysteme — Rohre und Formstücke aus Thermoplasten — Bestimmung der Vicat-Erweichungstemperatur (VST)

This European Standard was approved by CEN on 1994-08-22. CEN membersare bound to comply with the CEN/CENELEC Internal Regulations whichstipulate the conditions for giving this European Standard the status of anational standard without any alteration.Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to anyCEN member.This European Standard exists in three official versions (English, French,German). A version in any other language made by translation under theresponsibility of a CEN member into its own language and notified to theCentral 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 andUnited Kingdom.

CEN

European Committee for StandardizationComité Européen de NormalisationEuropäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© 1994 Copyright reserved to CEN membersRef. No. EN 727:1994 E

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EN 727:1994

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Foreword

This standard was prepared by CEN/TC 155, Plastics piping systems and ducting systems.This standard is based on ISO 2507:1982 Unplasticized polyvinyl chloride (PVC) pipes and fittings — Vicat softening temperature — Test method and specification, published by the International Organization for Standardization (ISO). It is a modification of ISO 2507:1982 for reasons of applicability to other plastics materials and/or other test conditions and alignment with texts of other standards on test methods.The modifications are:

— no material is mentioned;— the test force and the loading procedure have been aligned with those of ISO 306:1987.— test parameters, except those common to all plastics, are omitted;— no material-dependent requirements are given;— editorial changes have been introduced;

The material-dependent parameters and/or performance requirements are incorporated in the System Standard(s) concerned.No existing European Standard is superseded by this standard.This standard is one of a series of standards on test methods which support System Standards for plastics piping systems and ducting systems.This standard has been prepared under a mandate given to CEN by the Commission of the European Communities and the European Free Trade Association, and supports essential requirements of the EC Directive(s).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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EN 727:1994

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1 ScopeThis standard specifies a method for determining the Vicat softening temperature (VST) of pipes and fittings (see note) of thermoplastics materials, based on method B of ISO 306:1987, i.e. using a force of (50 ± 1) N and a rate of temperature increase of 50 °C/h.A measure of the temperature is obtainable only for those thermoplastics for which the softening becomes rapid.NOTE The term “fittings” is intended to also cover valves and other ancillaries made of thermoplastics material(s).

2 Normative referencesThis European Standard incorporates by dated or undated references 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.ISO 306:1987, Plastics — Thermoplastics materials — Determination of Vicat softening temperature.

3 PrincipleThe temperature at which a standard indenting tip (see note 1 to 4.1) under a constant force of (50 ± 1) N, penetrates 1 mm into the surface of a test piece cut from the wall of the pipe or fitting is determined when the temperature is raised at a uniform rate.The temperature at 1 mm penetration is quoted as VST in degrees Celsius.NOTE 1 It is assumed that the following test parameters are set by the standard making reference to this standard:

a) if necessary, the temperature and time for predrying the test pieces (see 4.2 and clause 6);b) if necessary, the temperature to be used to flatten the lower segment of a test piece (see 5.2.3);c) if necessary, for testing a pipe or fitting, or a homogeneous layer therefrom, with a wall thickness less than 1,2 mm, the method of test piece preparation and mounting (see 5.2.3 and 7.2);d) for structured-wall pipes and fittings, the method of test piece preparation and mounting (see 5.2.3 and 7.2).

NOTE 2 It is assumed that the significance of results from measurements which vary by more than 2 °C will be dealt with by the referring standard.

4 Apparatus4.1 Apparatus conforming to clause 4 of ISO 306:1987 as necessary for testing in accordance with method B when using a heating rate of (50 ± 5) °C/h. For a schematic diagram, see Figure 1.NOTE 1 ISO 306:1987 specifies the indenting tip as follows. Indenting tip, preferably of hardened steel, 3 mm long, of circular cross section, and area (1,000 ± 0,015) mm2, fixed at the bottom of the rod. The lower surface of the indenting tip shall be plane and perpendicular to the axis of the rod and free from burrs.NOTE 2 The uniform rate of temperature rise can be obtained by controlling the heat either manually or automatically, although the latter is strongly recommended. If a cooling coil is used in the liquid of the heating bath, in order to reduce the time required to lower the temperature between two consecutive tests, it is necessary to remove or drain such a coil before starting a new test, as boiling of residual coolant can affect the rate of temperature rise.

4.2 Oven with air circulation or other appropriate apparatus, if applicable (see clause 6), capable of maintaining the temperature specified by the referring standard, for predrying and/or annealing the test pieces.

5 Test pieces5.1 Sampling

5.1.1 Pipes

The test pieces shall consist of segments of rings, removed from the pipe, limited by cross sections and having the following dimensions:

— length: approximately 50 mm;— width: between 10 mm and 20 mm.

5.1.2 Fittings

The test pieces shall consist of segments of rings removed from the socket(s) or the spigot(s) of the fitting, limited by cross sections with a length as long as possible with a maximum of 50 mm. Where a fitting has no socket or spigots then the test piece shall be taken from a convenient section of the fitting.The width of each test piece shall be between 10 mm and 20 mm.The test pieces shall be cut from a zone which does not include a weld line, injection point or an insert.

5.2 Preparation

5.2.1 Wall thickness greater than 6 mm

For a wall thickness greater than 6 mm, reduce the thickness to 6 mm by machining the outer surface only of the pipe or fitting, using a technique which does not cause tangible heating of the non-planar surfaces of the test piece.NOTE Reduction to 6 mm (not 4 mm as given in ISO 306) is considered sufficient for the purposes of this standard.

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EN 727:1994

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If the socket of the fitting is threaded, machine the threaded part until a smooth surface is obtained.

5.2.2 Wall thickness between 2,4 mm and 6 mm

Test pieces of wall thickness between 2,4 mm and 6 mm shall be tested using the full wall thickness.

5.2.3 Wall thickness less than 2,4 mm

If the wall thickness of the pipe or fitting is less than 2,4 mm but not less than 1,2 mm, each test piece shall comprise two ring segments superimposed so as to obtain an overall thickness of at least 2,4 mm. Flatten the lower segment, which will serve as a base (see 7.2), by heating it to the specified temperature [see item b) of note 1 to clause 3] for 15 min, while resting a thin metal plate on it. The upper segment shall not be flattened.If the wall thickness of the pipe or fitting is less than 1,2 mm, the preparation and mounting of the test piece shall be as specified in the referring standard.

5.3 Number of test pieces

Use two test pieces for each test, but provide additional test pieces, in case the difference between the results is too great (e.g. > 2 °C, see 7.7).

6 ConditioningIf required by the referring standard, predry and/or anneal and/or condition the test pieces as specified in the referring standard [see item a) of note 1 to clause 3, and 4.2].

7 Procedure7.1 Raise the heating bath to a temperature about 50 °C lower than that anticipated for the VST of the product under test (see note 2 to 4.1).Maintain this temperature constant.7.2 Mount the test piece horizontally under the indenting tip of the unloaded rod (see Figure 1) so that the tip rests on the concave face of the test piece. Ensure that the interface between the base of the apparatus and the test piece, i.e. the underside of a stacked test piece (see 5.2.3) or the line of contact of a single test piece, is continuous.(Hence, in the case of pipes and fittings with a wall thickness of less than 2,4 mm, the indenting tip will rest on the concave surface of the non-flattened segment, the latter being placed on the flattened segment.) The indenting tip shall at no point be less than 3 mm from the edge of the test piece.7.3 Immerse the assembly in the heating bath (see 7.1). The bulb of the thermometer or sensitive part of the temperature-measuring instrument shall be at the same level as, and as close as possible to, the test piece.

Key

A Dial gauge micrometer

B Interchangeable weight

C Load-carrying plate

D Assembly of rod and indenting tip supporting the load- carrying plate

E Approximate level of liquid

F Indenting tip

G Test piece

H Flattened lower segment (see 5.2.3)

Figure 1 — Schematic diagram of apparatus for the determination of the Vicat softening

temperature

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EN 727:1994

© BSI 08-1999 5

7.4 After 5 min, with the indenting tip still in position, add the weight to the load-carrying plate (see Figure 1) so that the total thrust on the test piece is (50 ± 1) N. Then note the reading of the micrometer dial gauge (or other indentation-measuring instrument) (see Figure 1) or set the instrument to zero.7.5 Increase the temperature of the bath at a uniform rate of (50 ± 5) °C/h; stir the liquid well during the test.7.6 Note the temperature of the bath at which the indenting tip has penetrated into the test piece by (1 ± 0,01) mm beyond its starting position, as noted or set in accordance with 7.4, and record it as the Vicat softening temperature (VST) of the test specimen.7.7 Express as the VST, in degrees Celsius, of the pipe or fitting under test the arithmetic mean of the VSTs of the test pieces tested. If the difference between the two results exceeds 2 °C, record the individual results [see item f) of clause 8] and repeat the test once using a further set of at least two test pieces (see 5.3).

8 Test reportThe test report shall include the following information:

a) a reference to this standard and to the referring standard;b) a complete identification of the pipe or fitting tested;c) the thickness of the test pieces and, if applicable (see 5.2.3), whether they consisted of two parts or were otherwise specified by the referring standard;d) the liquid or other heat-transfer medium;e) if any, the method(s) of predrying, annealing and conditioning used (see clause 6);f) the Vicat softening temperature (VST) (the average of the results) obtained for the pipe or fitting or, if the difference between results for single test pieces exceeded 2 °C, the result for each of the test pieces and the results of the repeat test;g) any alterations in the appearance of the test pieces before and after their immersion;h) any factors which may have affected the results, such as any incidents or any operating details not specified in this standard;i) the date of test.

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BS EN 727:1995

© BSI 08-1999

List of references

See national foreword.

BS EN727:1995 BS 2782-11:Method 1103V:1995

BSI389 Chiswick High RoadLondonW4 4AL

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