CEN/TC 139/WG 9 - Testing of coil coated metals

This part of the EN 13523 series specifies the procedure for evaluating the behaviour of an organic coating on a metallic substrate during and after outdoor exposure. Panel design, preparation and the procedure for outdoor exposure are performed in accordance with EN 13523 19.
After washing of the panel, some dirt can remain on the panel. This remaining dirt can influence the accuracy and precision of readings of gloss and colour, performed on exposed panels, although carried out in accordance with the standards. Unlike other precise measurements, the objective of this European Standard is to report on trends in the corrosion and/or paint degradation behaviour of coil coated panels.

This document specifies the procedures for determining the dry-film thickness of an organic coating on a metallic substrate (coil coating).
Five appropriate methods are given in this document:
a)   magnetic induction;
b)   eddy current;
c)   micrometer;
d)   optical;
e)   ruggedized optical interference.
The methods are applicable only to products with smooth and flat substrates, but the coating itself can be textured. In that case, for methods a) and b), the average of a series of readings will represent an average of the thickness of the organic coating, while method c) will give the maximum thickness, method d) can provide the minimum, maximum and average thickness, and e) will give the total thickness.
Non-destructive continuous-web methods on measurement of dry-film thickness are only applicable on method a).

This part of the EN 13523 series specifies a procedure for the comparative evaluation of resistance to soiling of an organic coating on a metallic substrate (coil coating) in an outdoor exposure environment, particularly the soiling defect known as "Tiger stripes".

This document specifies the procedure for determining the difference in the colour of an organic coating on a metallic substrate by visual comparison against a standard using either diffuse natural daylight or artificial daylight in a standard booth.
NOTE   Results can differ between natural and artificial daylight.
It might be that two colour specimens will match in daylight but not under another light source. This phenomenon is known as metamerism (see EN 13523 3).
If a metameric match is to be reported in objective terms, spectrophotometric measurements (using CIE Standard Illuminants D65 and A) can be made, in accordance with EN 13523 3.
No statement is made about either the precision or the accuracy of this procedure since the results derived are neither in numerical form nor do they provide a pass/fail evaluation in objective terms. Therefore, this procedure is only intended to be used where the use of colour measuring instruments is not recommendable (evaluation of colour matches, inspection of metallic colours, etc.).
The standardization of such visual comparisons, by light sources, illuminating and viewing geometry and specimen size, provides for improved uniformity of results. This practice is essential for critical colour matching and is highly recommended for colour inspections.

This part of The EN 13523 series specifies the procedures for determining the resistance to salt spray (fog) of an organic coating on a metallic substrate (coil coating).
For steel, neutral salt spray (fog) is usually used, and for aluminium, acetic acid salt spray (fog).

This document specifies procedures for determining the instrumental colour difference (CIELAB   or  ) of an organic coating on a metallic substrate compared to another one used as a reference (usually called reference) and the metamerism depending on the illuminant.
When two colour specimens have identical spectral reflectance curves, they are matching under any illuminant irrespective of its spectral characteristics. This is termed a “spectral match”. It is also possible for two colour specimens having different spectral reflectance curves to match visually under a given light source but not to match under another light source with different spectral characteristics; such matches are termed "metameric".
One quantitative description of metamerism is the so-called "metamerism index".
Information on the metamerism index is of limited value where ΔE (instrumental colour difference for a given illuminant) is > 0,5. The metamerism index is not suited for determining the absolute colour difference or colour consistency of a given specimen at change of illuminant.
The colour difference under the reference illuminant is to be measured in colour coordinates L*, a* and b*.
Excluded from this method are organic coatings producing fluorescence and/or which are multicoloured, pearlescent or metallic.
Establishing a reference as well as the magnitude of an acceptable colour difference are not covered by this method.
Two methods are given in this document:
a)   instrumental colour difference measurement using a tristimulus colourimeter;
b)   instrumental colour difference measurement using a spectrophotometer or equivalent.
It is advised that care is taken when measuring e.g.
-   textured surfaces;
-   fluorescent coatings;
-   metameric coatings;
-   multi-coloured, pearlescent, metallic or special colour effect coatings.

This part of the EN 13523 series specifies the basic principles and procedure for determining the resistance of an organic coating on a metallic substrate (coil coating) to a combination of fluorescent UV radiation, and water condensation and temperature under controlled conditions.
Due to varied conditions which occur during natural weathering and the extreme nature of accelerated testing, correlation between the two cannot be expected.
Not all organic coatings will perform on an equal basis but a degree of correlation between the same generic type might be observed.

This document specifies the procedure for determining the resistance of an organic coating on a metallic substrate to penetration by scratching with a needle.
It is possible that with some aluminium alloys and thin gauge steel substrate below 0,4 mm, that rather than scratching, the needle will deform the substrate. Under these conditions, this test method is not applicable.
Soft coatings such as poly vinyl chloride (PVC) and structured coatings will not give a precise result due to the soft nature of the coating and/or the potential for the needle to snag.
The method is not applicable to conductive coatings.

This document describes the procedure for determining the resistance of an organic coating on a metallic substrate to humid atmospheres containing sulfur dioxide.

This document describes the procedure for determining objectively the chalking resulting from natural or artificial weathering of an organic coating on a metallic substrate.
The advantage of this procedure for measuring chalking of an organic coating is that the result can be read off immediately on an instrument. Subjective judgement by visual comparison of test specimens with reference specimens is not necessary.
Reproducible results can only be obtained by careful execution of the test. Special attention is paid to the adhesive tape and its application to the test surface.
The test method is not applicable to embossed coatings. In the case of textured coatings, the degree of texture will influence readings. Also, dirt collection can influence readings on outdoor weathered specimens.
NOTE   Different methods for assessing chalking are in use. The results of these different methods are not comparable.

This document specifies the procedure for determining the resistance to water immersion of an organic coating on a metallic substrate.
The test is applicable to all kinds of organic coatings, including metallics and embossed, textured, pearlescent and printed coatings. The results of the test give an indication of the resistance of the coil coated metal to water.
The method is not intended to reproduce any particular condition of condensation.

This document specifies a procedure for evaluating the resistance to humidity of an organic coating on a metallic substrate, by means of exposure in a humidity cabinet under controlled conditions.

This document specifies a procedure for evaluating the resistance to continuous condensation of an organic coating on a metallic substrate, by means of exposure in a humidity cabinet under controlled conditions.

This document specifies the overall scope of all parts of EN 13523, gives definitions common to all parts and describes how sampling and preparation of test panels for most of the individual test methods are to be carried out.

This document specifies the procedure for determining the gloss of an organic coating on a metallic substrate. Gloss is a characteristic of fundamental importance to the appearance of the coil coated product.
The apparatus requires a flat specimen of size greater than the aperture, thus, uneven surfaces cannot be measured.
This method is applicable to all pigmented and unpigmented coatings including metallic/pearlescent coatings. However, for textured coatings it is only indicative.

This document specifies the procedure for determining the resistance to cracking of an organic coating on a metallic substrate when bent through 135° to 180°. The degree of adhesion can also be evaluated.
Both folding and mandrel methods are considered. The folding method is more often used for practical purposes but where more precise determinations are required, the mandrel method is the preferred method.
The cylindrical bend method can also be used for a pass/fail decision by using an agreed mandrel.
The choice of the appropriate test method is limited by the thickness and/or the hardness of the substrate.
The feasibility of the test depends on the type and thickness of the substrate. During the procedure, the mandrel is not intended to deform.

This document specifies test procedures for assessing the effect of chemicals on the characteristics of an organic coating on a metallic substrate. It covers testing by using defined substances and to assess the change in characteristics such as discoloration, change in gloss, blistering, softening, swelling and loss of adhesion. Assessment of other phenomena can be agreed between the interested parties

This document defines terms of the procedure for determining the adhesion of an organic coating to a metallic substrate after indentation produced by slow deformation.
The resistance to cracking can also be evaluated.

This document describes a laboratory method for testing foam adhesion to an organic coating on a metallic substrate under dry and wet conditions.

This document specifies a method for determining the non-volatile matter by volume (NVV) of coating materials and related products by measuring the density of a dried coating for any specified temperature range and period of drying or curing. This method determines the non-volatile matter immediately after application.
Using the non-volatile matter by volume results obtained in accordance with this document, it is possible to calculate the spreading rate of coating materials.
The method specified in this document is the preferred method for air-drying materials. Its use for other materials has not yet been tested.
Annex B gives an overview of the existing methods for determination of non-volatile-matter content and volume of non-volatile matter.
This document is not applicable to coating materials in which the critical pigment volume concentration is exceeded.

This part of the EN 13523 series specifies two methods for determining the numerical evaluation of the adhesion of strippable films which have previously been applied to an organic coating on a metallic substrate.
Samples can be tested irrespective of whether the strippable film has been applied in the laboratory or on the production line.
NOTE   Method 1 is preferred for films with adhesive and method 2 for films without adhesive.

This part of EN 13523 specifies the panel design and describes the procedure for determining the resistance to outdoor exposure of an organic coating on a metallic substrate.

This part of the EN 13523 series specifies the procedure for evaluating the degree of curing by assessing the resistance of a cured organic coating film, applied on a metallic substrate, to a specified organic solvent.

The method specifies the gravimetric procedure for determining the non-volatile-matter content as a percentage by mass of the majority of thermally cured coil coatings and subsequently for determining the theoretical spreading rate. The method is not suitable for pure epoxy coil coatings.

This part of The EN 13523 series specifies the procedure for determining the resistance to blocking and/or pressure marking of an organic coating on a metallic substrate.

This part of the EN 13523 series specifies a procedure for evaluating the resistance of an organic coating on a metallic substrate (coil coating) in conditions of extreme humidity (acid, alkaline and/or neutral).

This part of EN 13523 describes the procedure to assess the relative hardness of an organic coating on a metallic substrate, by means of pencils of known hardness.
Smooth surfaces will give more accurate results but the method is also applicable for textured surfaces. The more pronounced the texture, the greater the unreliability of results.

This part of EN 13523 specifies the procedure for determining the resistance to cracking and/or pick-off on rapid deformation of an organic coating on a metallic substrate in terms of energy which the specimen will withstand.

This Part of EN 13523 describes the procedure for determining the behaviour of an organic coating on a metallic substrate (flat or bent specimens) when submitted to accelerated ageing by heating at a defined temperature for a defined period of time. It is not possible to test heat resistance in such way as to control all possible conditions of use. The aim of this test is therefore to furnish the basic test methods for the effect of heat. NOTE: Special applications may require that properties other than those mentioned in this part of EN 13523 be checked.

This part of EN 13523 describes the procedure for determining the resistance to abrasion and wear of an organic coating on a metallic substrate.

This document specifies procedures for determining the instrumental colour difference (CIELAB) of an organic coating on a metallic substrate compared to another one used as a reference (usually called reference) and the metamerism depending on the illuminant.
When two colour specimens have identical spectral reflectance curves, they are matching under any illuminant irrespective of its spectral characteristics. This is termed a “spectral match”. It is also possible for two colour specimens having different spectral reflectance curves to match visually under a given light source but not to match under another light source with different spectral characteristics; such matches are termed “metameric”.
One quantitative description of metamerism is the so-called “metamerism index”.
Information on the metamerism index is of limited value where ΔE (instrumental colour difference for a given illuminant) is > 0,5. The metamerism index is not suited for determining the absolute colour difference or colour consistency of a given specimen at change of illuminant.
The colour difference under the reference illuminant is to be measured in colour coordinates L*, a* and b*.
Excluded from this method are organic coatings producing fluorescence and/or which are multicoloured, pearlescent or metallic.
Establishing a reference as well as the magnitude of an acceptable colour difference are not covered by this method.
Two methods are given in this document:
a)   instrumental colour difference measurement using a tristimulus colourimeter;
b)   instrumental colour difference measurement using a spectrophotometer or equivalent.
It is advised that care is taken when measuring e.g.
—   textured surfaces;
—   fluorescent coatings;
—   metameric coatings;
—   multi-coloured, pearlescent, metallic or special colour effect coatings.

This part of the EN 13523 series specifies the procedure for evaluating the behaviour of an organic coating on a metallic substrate during and after outdoor exposure. Panel design, preparation and the procedure for outdoor exposure are performed in accordance with EN 13523 19.
After washing of the panel, some dirt can remain on the panel. This remaining dirt can influence the accuracy and precision of readings of gloss and colour, performed on exposed panels, although carried out in accordance with the standards. Unlike other precise measurements, the objective of this European Standard is to report on trends in the corrosion and/or paint degradation behaviour of coil coated panels.

This part of The EN 13523 series specifies the procedures for determining the resistance to salt spray (fog) of an organic coating on a metallic substrate (coil coating).
For steel, neutral salt spray (fog) is usually used, and for aluminium, acetic acid salt spray (fog).

This part of the EN 13523 series describes the procedure for determining the resistance of an organic coating on a metallic substrate to penetration by scratching with a needle.
It is possible that with some aluminium alloys and thin gauge steel substrate below 0,4 mm, that rather than scratching, the needle will deform the substrate. Under these conditions, this test method is not applicable.
Soft coatings such as poly vinyl chloride (PVC) and structured coatings will not give a precise result due to the soft nature of the coating and/or the potential for the needle to snag.
The method is not applicable to conductive coatings.

This part of the EN 13523 series specifies a procedure for the comparative evaluation of resistance to soiling of an organic coating on a metallic substrate (coil coating) in an outdoor exposure environment, particularly the soiling defect known as "Tiger stripes".

This part of the EN 13523 series specifies the procedures for determining the dry-film thickness of an organic coating on a metallic substrate (coil coating).
Four appropriate methods are given in this European Standard:
a)   magnetic induction;
b)   eddy current;
c)   micrometer;
d)   optical.
The methods are applicable only to products with smooth and flat substrates but the coating itself may be textured. In that case, for methods a) and b) the average of a series of readings will represent an average of the thickness of the organic coating, while method c) will give the maximum thickness and method d) can provide the minimum, maximum and average thickness.
Non-destructive continuous-web methods on measurement of dry-film thickness (see EN ISO 2808) are not dealt with.

This part of the EN 13523 series specifies the basic principles and procedure for determining the resistance of an organic coating on a metallic substrate (coil coating) to a combination of fluorescent UV radiation, and water condensation and temperature under controlled conditions.
Due to varied conditions which occur during natural weathering and the extreme nature of accelerated testing, correlation between the two cannot be expected.
Not all organic coatings will perform on an equal basis but a degree of correlation between the same generic type might be observed.

This part of the EN 13523 series specifies the procedure for determining the difference in the colour of an organic coating on a metallic substrate by visual comparison against a standard using either diffuse natural daylight or artificial daylight in a standard booth.
NOTE   Results might differ between natural and artificial daylight.
It might be that two colour specimens will match in daylight but not under another light source. This phenomenon is known as metamerism (see EN 13523 15).
If a metameric match is to be reported in objective terms, spectrophotometric measurements (using CIE Standard Illuminants D65 and A) should be made, in accordance with EN 13523-15.
No statement is made about either the precision or the accuracy of this procedure since the results derived are neither in numerical form nor do they provide a pass/fail evaluation in objective terms. Therefore, this procedure should only be used where the use of colour measuring instruments is not recommendable (evaluation of colour matches, inspection of metallic colours, etc.).
The standardization of such visual comparisons, by light sources, illuminating and viewing geometry and specimen size, provides for improved uniformity of results. This practice is essential for critical colour matching and is highly recommended for colour inspections.

This Part of EN 13523 describes the procedure for determining the colour stability of an organic coating on a metallic substrate when exposed to humid atmospheres containing sulfur dioxide. This method has been designed to provide an accelerated test for evaluating the colour fastness of coil coated products in atmospheres containing sulfur dioxide (typical of industrial atmospheres).

This Part of EN 13523 describes the procedure for determining objectively the chalking resulting from natural or artificial weathering of an organic coating on a metallic substrate. The advantage of this procedure for measuring chalking of an organic coating is that the result can be read off immediately on an instrument. Subjective judgement by visual comparison of test specimens with referencee specimens is not necessary. Experience to date with this test method has been based mainly on artificially weathered specimens. Reproductible results can only de obtained by careful execution of the test.

This Part of EN 13523 describes the procedure for determining the resistance to water immersion of an organic coating on a metallic substrate. The test is applicable to all kinds of organic coatings, including metallics and embossed, textured, pearlescent and printed coatings. The results of the test give an indication of the resistance of the coil coated metal to water. The method is not intended to reproduce any particular condition of condensation.

This Part of EN 13523 specifies a procedure for evaluating the humidity resistance of an organic coating (coil coating) on a metallic substrate, by means of exposure in a humidity cabinet under controlled conditions.

This Part of EN 13523 specifies a procedure for evaluating the condensation resistance of an organic coating (coil coating) on a metallic substrate, by means of exposure in a humidity cabinet under controlled conditions.

This Part of EN 13523 defines terms of the procedure for determining the metamerism of a colour match of an organic coating on a metallic substrate.
When two colour specimens have identical spectral reflection curves, they are matching under any illuminant irrespective of its spectral characteristics. This is termed a "spectral match". It is also possible for two colour specimens having different spectral reflection curves to match visually under a given light source but not to match under another light source with different spectral characteristics; such matches are termed "metameric".
One quantitative description of metamerism is the so-called "metamerism index".
The information of the metamerism index is of limited value where E (instrumental colour difference for a given illuminant, see EN 13523-3:2001) is > 0,5. The metamerism index is not suited for determining the absolute colour difference or colour constancy of a given specimen at change of illuminant.
The colour difference under the reference illuminant is to be measured in colour coordinates L*, a* and b* (see EN 13523-3:2001).
Excluded from this method are organic coatings producing fluorescence and/or which are multicoloured, pearlescent or metallic.

EN 13523 specifies test methods for organic coatings on coil coated metals.
This part of EN 13523 specifies the overall scope of all parts of EN 13523, gives definitions common to all parts and describes how sampling and preparation of test panels for most of the individual test methods are to be carried out.

This part of EN 13523 specifies procedures for determining the instrumental colour difference (CIELAB) of an organic coating on a metallic substrate.
Establishing a standard as well as the magnitude of an acceptable colour difference are not covered by this method.
Two appropriate methods are given in this part of EN 13523:
a)   instrumental colour difference measurement using a tristimulus colorimeter;
b)   instrumental colour difference measurement using a spectrophotometer or equivalent.
Care shall be taken when measuring e.g.
-   textured surfaces;
-   fluorescent coatings;
-   metameric coatings;
-   multi-coloured, pearlescent, metallic or special colour effect coatings.
In order to determine whether metamerism is present, the metamerism index is determined (see EN 13523-15) and/or a visual examination (see EN 13523-22) is performed with different artificial light sources.

This part of EN 13523 specifies the procedure for determining the gloss of an organic coating on a metallic substrate. Gloss is a characteristic of fundamental importance to the appearance of the coil coated product.
The apparatus requires a flat specimen of size greater than the aperture, thus, uneven surfaces cannot be measured.
This method is applicable to all pigmented and unpigmented coatings including metallic/pearlescent coatings. However, for textured coatings it is only indicative.

This part of EN 13523 specifies the procedure for determining the resistance to cracking of an organic coating on a metallic substrate when bent through 135° to 180°. The degree of adhesion may also be evaluated.
Both folding and mandrel methods are considered. The folding method is more often used for practical purposes but where more precise determinations are required, the mandrel method is recommended.
The cylindrical bend method may also be used for a pass/fail decision by using an agreed mandrel.
The choice of the appropriate test method is limited by the thickness and/or the hardness of the substrate.
The feasibility of the test depends on the type and thickness of the substrate. During the procedure, the mandrel should not deform.

This European Standard describes a laboratory method for testing foam adhesion to an organic coating on a metallic substrate under dry and wet conditions.

This Part of EN 13523 specifies test procedures for assessing the effect of chemicals on the characteristics of an organic coating on a metallic substrate. It covers testing by using defined substances and to assess the change in characteristics such as discoloration, change in gloss, blistering, softening, swelling and loss of adhesion. Assessment of other phenomena may be agreed between the interested parties.