A Preface
ISO (International Organization for Standardization) is a global alliance of national standards bodies (ISO member bodies). The development of international standards is usually carried out through ISO technical committees. Interested in the subject of which a technical committee has been set up for each of the members have the right to send representatives to attend in the committee. Government and non-governmental international organizations that liaize with standardization organizations are also involved in this work. ISO with the international electrotechnical commission (IEC) has electrician standardized all items close cooperation.

International standards are drafted according to the rules given in Part 2 of the ISO/IEC Directive.

The main task of the technical committee is to develop international standards. Technical committee through the draft international standards will be distributed to the members of the organization. As members of the international standard release need at least 75% of the agency for approval.

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

Please note that some of the contents of this document may belong to the patent right topic. ISO is not responsible for identifying any or all such patent rights.

ISO 19840 was developed by Technical Committee ISO/TC 35, Paints and varnishments, Subcommittee SC 14, Protective coating Systems for steel Structures.

Second edition cancel and replace the first edition (ISO 19840:2004), the first edition on technical and edit the revised as follows:

A) improve the description of the principle of the measurement method in 4.2;

B) introduced the eddy current measuring equipment instructions (see 5.2.4);

Figure 1 c) has nothing to do with the language;

d) In line A8 of Annex E, references to lines A7 and A8 have been corrected to A6 and A7;

e) In line B1 of Annex E, the reference to ISO 8503-1 has been corrected to read “relevant parts of ISO 8501”;

f) A bibliography is added for reference to ISO 8501-1 to ISO 8501-4.

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

Introduction
This international standard complements the ISO 12944 series of standards for measurement and acceptance of dry film thickness. If the specified or agreed, this standard can also be used in other applications.

The goal of this international standard is measurement on rough surface coating dry film thickness uniformity of practice. The chosen method requires the measurement of dry film thickness using a measuring instrument based on the principle of permanent magnet and induction magnet. Can use instruments using eddy current principle, but they are usually used in non-ferrous metal surface.

If the coating is applied to a rough steel substrate, the measurement of its dry film thickness is more complicated than that of a smooth surface. Rough steel substrates include substrates prepared by sandblasting cleaning or abrasion.

The influence of surface roughness on the measurement results increases with the depth of the profile, but the results also depend on the design of the measurement probe and the thickness of the coating.

Appendix A is informative and is a method based on adjusting the instrument to a known thickness on a rough surface. In this method, no correction values are used. In this standard, a single reading is used. Annex B describes a method of reading many times. The methods in Annexes A and B are used only when specified or agreed.

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

1 Scope
This international standard specifies the validation according to the nominal dry film thickness on the rough surface dry film thickness of the program, including the definition of the adjustment of the instruments used, inspection area, sampling plan, measurement methods and acceptance/reject criteria.

For the purpose of this standard, any given thickness are regarded as defined in ISO 12944-5 of the nominal thickness, dry film thickness is peak above the typical thickness of surface profile.

The procedures described in this standard are based on instruments using permanent magnets, electromagnets and eddy current types. Instrument accuracy is verified at zero and known thickness on a smooth surface and adjusted if necessary.

As a result, the rough on the coating on steel substrate for measuring the peak value of outline will be higher than the actual value. The dry film thickness above the profile peak was defined as the instrument reading minus the appropriate correction value.

Dry film thickness is using in smooth and flat steel based on the surface of readings to adjust the appropriate correction.

If specified or agreed on a single reading based on adjustment on a smooth, flat steel surface without the use of correction values, it is important to recognize that the method does not comply with this international Standard.

If the nominal dry film thickness of 40 microns or larger, this standard applies.

Note that if the nominal thickness is less than the surface roughness of the substrate, the measurement uncertainty will increase.

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

2 Normative references
The following references are required for the application of this document. For dated references, only for reference version. For undated references, the new version of the reference (including any revisions) applies.

ISO 2808, Paints and varnishes — Determination of film thickness

ISO 8503-1, preparation before coating of paint and related products of steel matrix – shot blast cleaning of steel substrate surface roughness properties – part 1: to evaluate the ISO surface profile of sandblasting the surface cleaning specification and the definition of the comparator

ISO 12944-1, Paints and varnishes – Corrosion protection of steel structures through protective coating systems – Part 1: General introduction

ISO 12944-2, Paints and varnishes – Corrosion protection of steel structures by protective coating systems – Part 2: Environmental classification

ISO 12944-3, Paints and varnishes – Corrosion protection of steel structures by protective coating systems – Part 3: Design considerations

ISO 12944-4, Paints and varnishes — Corrosion protection of steel structures by protective coating systems — Part 4: Types of surfaces and finishes

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

ISO 12944-5, Paints and varnishes — Corrosion protection of steel structures with protective coating systems — Part 5: Protective coating systems

ISO 12944-6, paints and varnishes – through the protective coating system for steel structure corrosion protection – part 6: laboratory performance test methods

ISO 12944-7, paints and varnishes – through the protective coating system for steel structure corrosion protection – part 7: paint job execution and supervision

ISO 12944-8, Paints and varnishes – Corrosion protection of steel structures by protective coating systems – Part 8: Development of new work and maintenance specifications

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

3.1 Dry film thickness EF5

When coating hardening residual film thickness on rough surface peak

3.2 Personal Reading

The number displayed by the film thickness meter

3.3 Corrected value

Allow the effect of sandblasting or other rough surfaces on the film thickness meter reading

3.4 separate dry film thickness

A single reading is subtracted from the corrected value

3.5 Average dry film thickness

Arithmetic mean of all individual dry film thicknesses in the detection area

3.6 nominal NDFT dry film thickness

For each layer of coating or the specified dry film thickness of the coating system, in order to achieve the required durability

3.7 Inspection Area

Sampling plan for its designated area, can be the entire structure or part of the whole structure

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

3.8 sampling plan

A plan that defines the number of measurements to be made on the inspection area

3.9 adjust

The process of aligning the readings of a dry film thickness gauge with known thickness values to improve the accuracy of a thickness gauge on a specific surface or within a specific part of its measuring range

3.10 Surface profile

The microscopic roughness of the surface

Note 1: This is usually expressed as the height of the main peaks relative to the main valleys.

12] [source: ISO 8503-1:

ISO 19840-2012 “Chinese Paints and varnishes-Criteria for the measurement and acceptance of dry film thickness on rough surfaces”

3.11 Maximum dry film thickness

The maximum allowable dry film thickness beyond which the performance of the paint or paint system may be impaired

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