1、 ISO 2012 Paints and varnishes Corrosion protection of steel structures by protective paint systems Measurement of, and acceptance criteria for, the thickness of dry films on rough surfaces Peintures et vernis Anticorrosion des structures en acier par systmes de peinture Mesure et critres dacceptati
2、on de lpaisseur dun feuil sec sur des surfaces rugueuses INTERNATIONAL STANDARD ISO 19840 Second edition 2012-09-01 Reference number ISO 19840:2012(E) ISO 19840:2012(E) ii ISO 2012 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2012 All rights reserved. Unless otherwise specified, no part of t
3、his publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1
4、211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ISO 19840:2012(E) ISO 2012 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions . 2 4 Principle . 3 4.1
5、 General . 3 4.2 Principle of the applicable measurement methods . 3 5 Apparatus and materials . 3 5.1 General . 3 5.2 Measurement equipment using a magnetic field 4 5.3 Materials . 4 6 Procedure 5 6.1 Sampling plan . 5 6.2 Adjustment of the instrument 5 6.3 Measurement 6 7 Correction values 6 8 Exp
6、ression of results . 7 9 Acceptance/rejection criteria . 7 10 Test report . 8 Annex A (informative) Method based on adjusting the instrument to known thicknesses on a rough surface . 9 Annex B (informative) Multiple readings 11 Annex C (informative) Areas requiring special consideration .12 Annex D
7、(normative) Determination of a specific correction value 13 Annex E (informative) Example of a test report form14 Bibliography .16 ISO 19840:2012(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work
8、of preparing International Standards is normally carried out through ISO technical committees. 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-government
9、al, in liaison with ISO, also take part in the work. ISO collaborates closely with the 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 2. The mai
10、n task of technical committees is to prepare International Standards. Draft International 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. Att
11、ention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 19840 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 14, Prote
12、ctive paint systems for steel structures. This second edition cancels and replaces the first edition (ISO 19840:2004), which has been technically and editorially revised as follows: a) the descriptions in 4.2 of the principle of the measurement methods have been improved; b) a description of eddy cu
13、rrent measurement equipment has been introduced (see 5.2.4); c) Figure 1 has been made language-independent; d) in line A8 in Annex E, the references to lines A7 and A8 have been corrected to A6 and A7; e) in line B1 in Annex E, the reference to ISO 8503-1 has been corrected to “the relevant part of
14、 ISO 8501”; f) a Bibliography has been added for the informative references ISO 8501-1 to ISO 8501-4. iv ISO 2012 All rights reserved ISO 19840:2012(E) Introduction This International Standard supplements the ISO 12944 series with regard to the measurement and acceptance criteria for the thickness o
15、f a dry film. If specified or agreed, the standard can also be used for other applications. The objective of this International Standard is to achieve uniformity of practice for measuring the dry-film thickness of a coating on a roughened surface. The chosen methods entail the measurement of dry-fil
16、m thickness using measurement instruments based on the permanent magnet principle and the inductive magnet principle. Instruments using the eddy current principle can be used but their use is normally on non-ferrous metal surfaces. If a coating is applied to a roughened steel substrate, the measurem
17、ent of its dry-film thickness is more complicated than for smooth surfaces. Roughened steel substrates include those prepared by abrasive blast- cleaning or abrading. The effect of surface roughness on the measurement result increases with profile depth, but the result will also depend on the design
18、 of the measurement probe and the thickness of the coating. Annex A, which is informative, is a method based on adjusting the instrument to known thicknesses on a rough surface. In this method, no correction value is used. In this standard, individual readings are used. Annex B describes a method fo
19、r multiple readings. The methods in Annexes A and B are intended to be used only if specified or agreed. ISO 2012 All rights reserved v Paints and varnishes Corrosion protection of steel structures by protective paint systems Measurement of, and acceptance criteria for, the thickness of dry films on
20、 rough surfaces 1 Scope This International Standard specifies a procedure for the verification of dry-film thickness against nominal dry- film thickness on rough surfaces, including the adjustment of the instruments used, the definition of inspection areas, sampling plans, measurement methods and ac
21、ceptance/rejection criteria. For the purposes of this standard, any specified thickness is taken to be nominal as defined in ISO 12944-5, and the dry-film thickness is the typical thickness above the peaks of the surface profile. The procedure described in this International Standard is based on the
22、 use of instruments of the permanent magnet, electromagnet and eddy current type. Instrument accuracy is verified both at zero and at a known thickness on a smooth surface and adjusted if necessary. Measurements taken on a coating on a roughened steel substrate will therefore be higher than the actu
23、al value above the peaks of the profile. The thickness of the dry film above the peaks of the profile is defined as the instrument reading minus an appropriate correction value. The dry-film thickness is obtained by using the appropriate correction value applied to readings based on adjustment on a
24、smooth, flat steel surface. Where individual readings, based on adjustment on a smooth, flat steel surface without the use of correction values, are specified or agreed, it is important to recognize that this method does not conform with this International Standard. This standard is applicable if th
25、e nominal dry-film thickness is 40 m or greater. NOTE If the nominal thickness is less than the surface roughness of the substrate, the uncertainty of the measurement will increase. 2 Normative references The following referenced documents are indispensable for the application of this document. For
26、dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2808, Paints and varnishes Determination of film thickness ISO 8503-1, Preparation of steel substrates before application of paints and rela
27、ted products Surface roughness characteristics of blast-cleaned steel substrates Part 1: Specifications and definitions for ISO surface profile comparators for the assessment of abrasive blast-cleaned surfaces ISO 12944-1, Paints and varnishes Corrosion protection of steel structures by protective p
28、aint systems Part 1: General introduction ISO 12944-2, Paints and varnishes Corrosion protection of steel structures by protective paint systems Part 2: Classification of environments ISO 12944-3, Paints and varnishes Corrosion protection of steel structures by protective paint systems Part 3: Desig
29、n considerations ISO 12944-4, Paints and varnishes Corrosion protection of steel structures by protective paint systems Part 4: Types of surface and surface preparation INTERNATIONAL STANDARD ISO 19840:2012(E) ISO 2012 All rights reserved 1 ISO 19840:2012(E) ISO 12944-5, Paints and varnishes Corrosi
30、on protection of steel structures by protective paint systems Part 5: Protective paint systems ISO 12944-6, Paints and varnishes Corrosion protection of steel structures by protective paint systems Part 6: Laboratory performance test methods ISO 12944-7, Paints and varnishes Corrosion protection of
31、steel structures by protective paint systems Part 7: Execution and supervision of paint work ISO 12944-8, Paints and varnishes Corrosion protection of steel structures by protective paint systems Part 8: Development of specifications for new work and maintenance 3 Terms and definitions For the purpo
32、ses of this document, the following terms and definitions apply. 3.1 dry-film thickness DFT thickness of a coating remaining over the peaks of a rough surface when the coating has hardened 3.2 individual reading figure displayed by the film thickness instrument 3.3 correction value allowance for the
33、 influence of the abrasive blast-cleaned or otherwise roughened surface on the reading of the film thickness instrument 3.4 individual dry-film thickness individual reading minus a correction value 3.5 mean dry-film thickness arithmetic mean of all the individual dry-film thicknesses in the inspecti
34、on area 3.6 nominal dry-film thickness NDFT dry-film thickness specified for each coat or for the whole paint system to achieve the required durability 3.7 inspection area designated area for which a sampling plan is established and which can be the whole structure or sections of the whole structure
35、 3.8 sampling plan plan which defines the number of measurements to be taken on an inspection area 3.9 adjustment process of aligning the readings of a dry-film thickness gauge to known thickness values in order to improve the accuracy of the gauge on a specific surface or within a specific portion
36、of its measurement range 2 ISO 2012 All rights reserved ISO 19840:2012(E) 3.10 surface profile micro-roughness of a surface NOTE This is generally expressed as the height of the major peaks relative to the major valleys. ISO 8503-1:2012 3.11 maximum dry-film thickness highest acceptable dry-film thi
37、ckness above which the performance of the paint or the paint system might be impaired 4 Principle 4.1 General The thickness of the coating on the prepared steel surface is measured using one of the non-destructive methods described in ISO 2808. The measurement instruments used are adjusted. For the
38、measurement, a sampling plan is laid down as well as an appropriate correction value. This International Standard also specifies criteria which are used with regard to acceptance or non-acceptance of film thickness values. 4.2 Principle of the applicable measurement methods 4.2.1 Permanent-magnet pr
39、inciple Instruments of this type produce a static magnetic field. They measure the magnetic field strength between a permanent magnet and a magnetic substrate. The magnetic field strength is related to the coating thickness. 4.2.2 Pull-off permanent-magnet principle Instruments of this type produce
40、a static magnetic field. They measure the force required to overcome the magnetic attraction between a magnet and a magnetic substrate. This force is related to the coating thickness. 4.2.3 Magnetic-induction principle Instruments of this type use an electronic probe to generate a magnetic field wit
41、h either a permanent magnet (with a Hall sensor) or an electromagnet (with an electromagnetic induction coil). They produce a coating thickness measurement by measuring the change in magnetic field strength within their probes due to the proximity of the magnetic substrate. The magnetic field streng
42、th is related to the coating thickness. NOTE Other methods using a similar principle are available. 4.2.4 Eddy current principle Instruments of this type mainly used on non-magnetic metal substrates produce a varying high-frequency magnetic field. They measure the magnetic field strength produced by
43、 eddy currents caused by the probe in a conductive substrate. The magnetic field strength is related to the coating thickness. 5 Apparatus and materials 5.1 General All instruments for measuring dry-film thicknesses will give variable values within very small areas on roughened surfaces due to the i
44、nfluence of the surface roughness and the variations inherent in the method(s) used to apply the paint. ISO 2012 All rights reserved 3 ISO 19840:2012(E) The type of measurement equipment and material shall be specified or agreed between the interested parties before the measurements commence. 5.2 Me
45、asurement equipment using a magnetic field 5.2.1 Electromagnet Instruments using this principle may be equipped with either a single- or twin-pole probe. This equipment may incorporate a statistical capability. This enables the minimum, maximum, mean and standard deviation to be calculated. When usi
46、ng a twin-poled instrument, it is recommended that the instrument be moved to positions 90, 180 and 270 from the original position where the first reading was made, for example the instrument is pivoted around the first point of measurement. The mean value of the four readings taken should be determ
47、ined and represents the dry-film thickness at the particular spot. In this case, the arithmetic mean value of the four readings is used in place of an individual reading. 5.2.2 Permanent magnet Instruments of this type incorporate a permanent magnet with one or more poles in the form of hemispherica
48、l contacts which are placed on the coated surface. When using a twin-poled instrument, it is recommended that the instrument be moved to positions 90, 180 and 270 from the original position where the first reading was made, for example the instrument is pivoted around the first point of measurement.
49、 The mean value of the four readings taken should be determined and represents the dry-film thickness at the particular spot. In this case, the arithmetic mean value of the four readings is used in place of an individual reading. 5.2.3 Magnetic pull-off This type of instrument most commonly incorporates a permanent magnet to which is attached a spring. Various forms of the instrument are available, including a simple pencil type, a spring balance type and another type to which tension is app
