scope:

This International Standard is one of a series of standards dealing with the sampling and testing of paints, varnishes and related products.

It specifies a test method for determining under defined conditions the resistance of a single coating or a multi-coat system of paint, varnish or related product to penetration by scratching with a hemispherically tipped needle. Penetration of the needle is to the substrate, except in the case of a multi-coat system, where the penetration of the needle may be either to the substrate or to an intermediate coat.

The method is intended for application as follows:

a) either as a pass/fail test, by testing with a single specified load applied to the needle to assess compliance with a particular specification;

b) or by applying increasing loads to the needle to determine the minimum load at which the coating is penetrated.