DIN EN ISO 2409:2013-06

The standard specifies a test method for assessing the resistance of paint coatings to separation from substrates when a right-angle lattice pattern is cut into the coating, penetrating through to the substrate. The property determined by this empirical test procedure depends, among other factors, on the adhesion of the coating to either the preceding coat or the substrate. This procedure is not to be regarded, however, as a means of measuring adhesion. Where a measurement of adhesion is required, the method described in ISO 4624 may be used. Although the test is primarily intended for use in the laboratory, the test is also suitable for field testing. For substrates that are inhomogeneous and/or that have a considerably lower cohesion than the coating being tested (for example, certain plaster surfaces) it is not possible to make cuts having a uniformly low depth. This method is therefore not suitable for such substrates. The results of field tests on coatings with different exposure conditions and carried out at different times are not comparable. Normally, climatic conditions do not remain constant over time and they vary from location to location; for this reason the test conditions specified in this standard cannot be maintained in field tests. The method specified may be used either as a pass/fail test or, where circumstances are appropriate, as a six-step classification test. When applied to a multi-coat system, assessment of the resistance to separation of individual layers of the coating from each other can be made. The test can be carried out on finished objects and/or on specially prepared test specimens. Although the method is applicable to paint on hard (for example, steel and plastics) and soft (for example, wood and plaster) substrates, these different substrates need a different test procedure. The method is not suitable for coatings of total thickness greater than 250 µm or for textured coatings. The method, when applied to coatings designed to give a rough patterned surface, will give results which will show too much variation (see also ISO 16276-2). The committee responsible for this standard is NA 002-00-07 AA "Allgemeine Prüfverfahren für Beschichtungsstoffe und Beschichtungen" ("General test methods for coating materials and coatings") at DIN.