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BRITISH STANDARD BS 3900-H4:1983ISO4628/4:1982[Cracking]

Methods of test for paints

Part H4: Designation of degree of cracking

[ISO title: Paints and varnishes Evaluation of degradation of paint coatings Designation of intensity, quantity and size of common types of defect Part 4: Designation of degree of cracking]

It is recommended that this Part be read in conjunction with the general information in the Introduction to BS 3900, issued separately.

UDC 667.613.72:620.191.33

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BS 3900-H4:1983

This British Standard, having been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee, was published under the authority of the Board of BSI and comes into effect on29 April 1983

BSI 03-1999

The following BSI references relate to the work on this standard:Committee reference PVC/10Draft for comment 80/50329 DC

ISBN 0 580 13095 9

National foreword

This Part of BS 3900 has been prepared under the direction of the Pigments, Paints and Varnishes Standards Committee. It is identical with ISO 4628/4-1982 Paints and varnishes Evaluation of degradation of paint coatings Designation of intensity, quantity and size of common types of defect Part 4: Designation of degree of cracking, published by the International Organization for Standardization (ISO).Terminology and conventions. The text of the international standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following.Wherever the words International Standard appear, referring to this standard, they should be read as British Standard; and wherever the words this part of ISO 4628 and ISO 4628/4 appear they should be read as this Part of BS 3900 and BS 3900-H4 respectively.

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 pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4, 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.

Cross references

International Standards Corresponding British Standards

BS 3900 Methods of test for paintsISO 4628/1-1982 Part H1:1983 Designation of intensity, quantity and

size of common types of defect: general principles and rating schemes(Identical)

ISO 4628/2-1982 Part H2:1983 Designation of degree of blistering(Identical)

ISO 4628/3-1982 Part H3:1983 Designation of degree of rusting(Identical)

ISO 4628/5-1982 Part H5:1983 Designation of degree of flaking(Identical)

Amendments issued since publication

Amd. No. Date of issue Comments

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BS 3900-H4:1983

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Contents

PageNational foreword Inside front cover0 Introduction 11 Scope and field of application 12 Reference 13 Rating 14 Test report 1Figure 1 Cracking without preferential direction 2Figure 2 Cracking with one preferential direction 3Table Rating scheme for the designation of the size of cracks 1Publications referred to Inside back cover

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BS 3900-H4:1983

BSI 03-1999 1

0 IntroductionThis International Standard is one of a series of standards dealing with the sampling and testing of paints, varnishes and related products.The other parts of ISO 4628 already published or in course of preparation are:

Part 1: General principles and rating schemes; Part 2: Designation of degree of blistering; Part 3: Designation of degree of rusting; Part 5: Designation of degree of flaking; Part 6: Designation of degree of chalking.1)

Part 1 of ISO 4628 defines the system for designating the quantity and and size of common types of defects of paint coatings and outlines the basic principles of the system in respect of designation of the quantity and size of defects, in particular the defects caused by ageing and weathering.Parts 2 to 6 provide auxiliary pictorial or other reference scales for rating particular types of defect. As far as possible, these scales are based on existing well-established schemes.

1 Scope and field of applicationThis part of ISO 4628 provides pictorial standards for designating the degree of cracking of paint coatings.

2 ReferenceISO 4628/1, Paints and varnishes Evaluation of degradation of paint coatings Designation of intensity, quantity and size of common types of defect Part 1: General principles and rating schemes.

3 RatingRate the quantity of cracking by reference to Table 2 of ISO 4628/1 and using as examples Figure 1 or Figure 2, depending on the type of cracking.NOTE Figure 1 shows cracking without preferential direction and Figure 2 shows cracking in one preferential direction which occurs with anisotropic substrates such as wood. Other forms of cracking occur, but the principles of rating of quantity remain the same.

Designate the average size of the Cracks according to the classification given in the table.

Table Rating scheme for the designation of the size of cracks

If possible, indicate the depth of cracking by reference to the level in the coating system to which the cracks penetrate.Three main types of failure by cracking are to be distinguished:

a) surface cracks which do not fully penetrate the top coat;b) cracks which penetrate the top coat, the underlying coat(s) being substantially unaffected;c) cracks which penetrate the whole coating system.

4 Test reportThe test report shall contain at least the following information:

a) the type and identification of the product tested;b) a reference to this International Standard (ISO 4628/4);c) the numerical rating of the quantity of cracking;d) the numerical rating of the size of cracking;e) the depth of cracking (a, b, or c), where possible, for example:

cracking 2 (S3) bIf necessary, the standard assessment may be amplified in words, for example linear cracking. The use of such comments shall, however, be avoided wherever possible;e) the date of the examination.

1) At present at the stage of draft.

Class Size of cracks

0 not visible under X 10 magnification

1 only visible under magnification up to X 10

2 just visible with normal corrected vision

3 clearly visible with normal corrected vision

4 large cracks generally up to 1 mm wide

5 very large cracks generally more than 1 mm wide

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BS 3900-H4:1983

2 BSI 03-1999

Figure 1 Cracking without preferential direction

[Panels of 1 to 2 dm2 (see Table 2 of ISO 4628/1)]

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BS 3900-H4:1983

BSI 03-1999 3

Figure 2 Cracking with one preferential direction(for example due to brush marks or wood grain)[Panels of 1 to 2 dm2 (see Table 2 of ISO 4628/1)]

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BS 3900-H4:1983

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Publications referred to

See national foreword.

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edtDisclaimer: This is an uncontrolled copy. Ensure use of the most current version of this document by searching British Standards Online at bsonline.techindex.co.ukWMDate: on March 26, 2002WMName: chris sharkey

edtMessage: A single copy of this British Standard is licensed to

edtBS: British Standard