BS DD ISO TR 15235-2001 Preparation of steel substrates before application of paints and related products - Collected information on the effect of levels of water-soluble salt cont.pdf

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1、DRAFT FOR DEVELOPMENT DD ISO/TR 15235:2001 Preparation of steel substrates before application of paints and related products Collected information on the effect of levels of water-soluble salt contamination ICS 25.220.10; 77.080.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT L

2、AWDD ISO/TR 15235:2001 This Draft for Development, having been prepared under the direction of the Sector Policy and Strategy Committee for Building and Civil Engineering, was published under the authority of the Standards Policy and Strategy Committee on 7 December 2001 BSI 7 December 2001 ISBN 0 5

3、80 38753 4 National foreword This Draft for Development reproduces verbatim ISO/TR 15235:2001. This publication is not to be regarded as a British Standard. It is being issued in the Draft for Development series of publications and is of a provisional nature because the source document is an ISO Tec

4、hnical Specification which is not an international standard. It should be applied on this provisional basis, so that information and experience of its practical application may be obtained. Comments arising from the use of this Draft for Development are requested so that UK experience can be reporte

5、d to the international organization responsible for its conversion into an international standard. A review of this publication will be initiated 2 years after its publication by the international organization so that a decision can be taken on its status at the end of its three-year life. The comme

6、ncement of the review period will be notified by an announcement in Update Standards. According to the replies received by the end of the review period, the responsible BSI Committee will decide whether to support the conversion into an international standard. Comments should be sent in writing to t

7、he Secretary of BSI Technical Committee STI/21, Surface preparation of steel, at 389 Chiswick High Road, London W4 4AL, giving the document reference and clause number and proposing, where possible, an appropriate revision of the text. A list of organizations represented on this committee can be obt

8、ained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find”

9、facility of the BSI Standards Electronic Catalogue. Summary of pages This document comprises a front cover, an inside front cover, the ISO/TR title page, pages ii to v, a blank page, pages 1 to 24, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates whe

10、n the document was last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO/TR 15235:2001(E)TECHNICAL REPORT ISO/TR 15235 First edition 2001-10-15 Preparation of steel substrates before application of paints and related products Collected information on the effect

11、 of levels of water-soluble salt contamination Prparation des subjectiles dacier avant application de peintures et de produits assimils Conseils sur les teneurs en contamination des sels solubles dans leau ISO/TR 15235:2001(E) ii ISO/TR 15235:2001(E) iiiContents Page Foreword.iv Introduction.v 1 Sco

12、pe 1 2 Conclusions .1 3 Terms and definitions .2 4 Sequential collection of data2 5 Protocol for assessing surface contamination 5 6 Recommended test protocol to investigate the influence of salt contamination on coating service life 5 7 Other standards of interest 5 Annex A (informative) Summary of

13、 data from bibliographic references.6 Annex B (informative) Data from a paint manufacturer.14 Annex C (informative) Coating-system manufacturers recommendations regarding toleration of salt contamination on a steel surface before application of paints or related products 16 Annex D (informative) Dat

14、a supplied by Japan (see 4.2) 19 Annex E (informative) Assessment of soluble chloride and/or sulfate contamination on a steel surface Surface inspection protocol.21 Annex F (informative) Recommended test procedure when investigating the influence of soluble chloride and/or sulfate contamination on c

15、oating service life .22 Bibliography23 ISO/TR 15235:2001(E) iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical com

16、mittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

17、 International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees is to prepare International Standards. Draft Internatio

18、nal Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In exceptional circumstances, when a technical committee has collected data of a differen

19、t kind from that which is normally published as an International Standard (“state of the art“, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until

20、 the data it provides are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this Technical Report may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TR 15235 was prepar

21、ed by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 12, Preparation of steel substrates before application of paints and related products. ISO/TR 15235:2001(E) vIntroduction The performance of paints and related products applied to steel can be significantly affected by the pr

22、esence of water-soluble salt contaminants on a steel surface. Sources of salt contamination are numerous. In the painting industry, the blasting abrasive itself, the paint ingredients (particularly pigments), and the rinse water that may be used in wet cleaning methods can all be sources of salt con

23、tamination. In addition, salts settle from the atmosphere during fogs, dews, inversions, and rain, and they may also be deposited from chemical splashes or air pollutants. De-icing salts, which are used on highways and bridges in cold climates, may remain on the steel surfaces. Furthermore, some ste

24、el surfaces, during service, come into direct contact with salts, e.g. ships carrying salt water ballast in steel tanks or vessels with salt- containing cargoes. Unless salts are removed from a steel surface prior to painting, problems may occur that lead to poor paint performance. Salts on the stee

25、l surface can absorb moisture from the air, cause osmotic blistering of the paint system, and accelerate the rate of corrosion. Removal of salts is often difficult, and the salts accelerate pitting corrosion. The salt contaminant can remain in the bottom of pits, often beneath the corrosion product.

26、 In order to adequately remove salts from the surface, it is often necessary not only to remove the corrosion product, but also to flush the salt from within the corrosion pits. The performance of a paint system applied over a salt-contaminated surface depends on the service environment, the type an

27、d design of the paint system, the thickness of the paint, and the nature and amount of salt contaminants. International Standards ISO 8501 and ISO 8502 have been prepared to provide methods of assessing visually or by chemical analysis the presence and surface concentration of contaminants, and ISO

28、8504 provides guidance on methods for cleaning steel surfaces. These International Standards, however, do not contain guidance on the levels of salt contamination that can be tolerated by paint systems. This document provides information on the levels of water-soluble chloride and sulfate salt conta

29、mination that will minimize the risk of coating failure. The information in this document is based on an evaluation of published data from technical literature, as well as unpublished data from coating-system manufacturers and users. TECHNICAL REPORT ISO/TR 15235:2001(E)1Preparation of steel substra

30、tes before application of paints and related products Collected information on the effect of levels of water-soluble salt contamination 1 Scope This Technical Report provides information on the effect of water-soluble chloride and sulfate contamination levels on steel surfaces, before the applicatio

31、n of paint or related products to surfaces prepared in accordance with standard mechanical or blast-cleaning surface preparation methods. NOTE The tolerance for water-soluble salt contamination may be different for different paint types. This information may be used when evaluating the adequacy of s

32、urface preparation prior to painting. This document is concerned only with measured levels of salt contamination based upon either laboratory or field testing. The levels of soluble chloride and sulfate discussed in this document are to be compared using soluble surface densities of the species as d

33、etermined after extraction in accordance with ISO 8502-6 (the Bresle method), or other methods giving equivalent results. Total soluble-salt contamination may be determined by conductometric testing, but such testing will not determine the nature and concentration of the specific salts present, e.g.

34、 whether chloride or sulfate is present, or its concentration. This document does not define specific levels of cleanliness or methods of salt removal. 2 Conclusions From the information in this Technical Report, it is apparent that there is a great variation in the depth of knowledge related to con

35、tamination levels of water-soluble salts (chlorides and sulfates) and their subsequent effect on the performance of paints and related products in various environments. Most knowledge relates to coatings subjected to immersed conditions, which are judged to be the most severe and therefore, in pract

36、ice, the most costly should failure occur. The data obtained from paint manufacturers has tended to concentrate on this area and therefore provides the best guidance values for the levels of water-soluble salts with respect to coatings used for protection in immersed conditions. In other, less deman

37、ding, environments, often protected by less sophisticated coatings than those used for immersed conditions, information on water-soluble salt levels and their effect on these coatings is scarce. It is acknowledged that, in these areas, further experimental work is required to produce data, but this

38、is likely to take a significant period of time. It is in this context that ISO/TC35/SC12 has concluded that the information available does not provide the necessary confidence to provide guidance values that can be issued as an ISO standard. The publication of ISO standards for methods of determinin

39、g the water-soluble salt levels on steel surfaces, together with the recommended test procedure given in annexes E and F should provide further data that can be assessed for incorporation into a future ISO standard. ISO/TR 15235:2001(E) 2 3 Terms and definitions For the purposes of this Technical Re

40、port, the following terms and definitions apply. 3.1 contaminants water-soluble salts present on the steel surface immediately prior to painting NOTE Only water-soluble chloride and sulfate ions are considered in this document. 3.2 service environment conditions to which the coating system is expose

41、d in service NOTE This report covers six types of service environment, defined by the atmospheric-corrosivity categories given in ISO 12944-2: a) IM-1: fresh- water immersion; b) IM-2: sea or brackish-water immersion; c) C3 medium: industrial atmospheric exposure; d) C4 high: industrial atmospheric

42、exposure; e) C5-I very high (industrial): high-humidity/aggressive industrial atmospheric exposure; f) C5-M very high (marine): high-salinity marine exposure. 4 Sequential collection of data 4.1 Review of published papers on the effects of salt contamination 4.1.1 Sources A comprehensive review of t

43、he technical literature was conducted using journals and electronic databases that examined published literature. A total of 168 relevant articles were reviewed. NOTE A list of these articles is available from the Netherlands Standards Institute (NEN), which holds the Secretariat of ISO/TC35, Paints

44、 and varnishes. 4.1.2 Criteria for evaluation From such a large database, the following criteria were established to provide a basis for evaluation: a) The paper/report contained information about original work and was not simply a report of others efforts; b) The paper/report correlated coating per

45、formance with salt contamination levels on steel surfaces. A list of the papers and reports which met these criteria and provided useful information is given in the bibliography, and a summary of the findings is given in annex A. NOTE The above references given in the bibliography were obtained as a

46、 result of an extensive computer literature search done in 1995. The computer results were examined to determine whether the literature reported original testing, or was a compilation of work done by others. Only that literature reporting original test results is given. It is likely there is origina

47、l published work since 1995 that will be suitable for future inclusion in the tables. Researchers are encouraged to conduct testing as described in annexes E and F, and to submit results to the Secretariat of ISO/TC 35/SC 12. ISO/TR 15235:2001(E) 34.1.3 Parameters relating to the rate of paint syste

48、m failure Some parameters relating to the rate of failure of the paint system were: a) The type of exposure/service environment. b) The type of contaminant (chloride, sulfate, etc.). c) The type of paint system (and formulation within generic types), thickness and number of coats. d) The application

49、 method (brush, roller, spray, etc.), particularly for the primer coat. e) The contamination level. The extraction of soluble contaminants from a steel surface depends upon the extraction conditions, e.g. extraction liquid, temperature and extraction time. Comparable results may be obtained by extraction in accordance with ISO 8502-6 (the Bresle method), or methods giving equivalent results. Analysis of chloride and sulfate may be made by methods described in ISO 8502-9 and ISO 8502-10. f) The type of failure (blisters, rust, etc.). 4.1.4 Use of contamination levels The data