Paints and varnishes. Determination of film thickness

BS EN ISO 2808:2007, BS 3900-C5:2007 Paints and varnishes. Determination of film thickness

BS EN ISO 2808 is an international standard that describes a number of methods that are applicable to the measurement of the thickness of coatings applied to a substrate. Methods for determining wet-film thickness, dry-film thickness and the film thickness of uncured powder layers are described. Reference is made to individual standards where these exist. Otherwise the method is described in detail.

An overview on the methods is included, in which the field of application, existing standards and the precision are specified for the individual methods.

This International Standard also defines terms concerning the determination of film thickness.

The main changes are as follows:

The structure of the standard has been changed into four main clauses:

• Determination of wet-film thickness;
• Determination of dry-film thickness;
• Determination of the thickness of uncured powder layers; and
• Measurement of film thickness on rough surfaces.

Methods using photothermal, radiological and acoustic techniques have been added.

The split-beam method has been deleted as such instruments are no longer manufactured.

Measurement of film thickness depends on the following steps:

• Calibration of the measurement instrument, typically performed by the manufacturer or by any qualified laboratory
• Verification of the instrument (an accuracy check performed by the user at regular intervals, typically before each series of measurements)
• Subsequent adjustment, if necessary, of the instrument so that the thickness readings it gives match those of a specimen of known thickness. For a dry-film thickness gauge this would mean zeroing it on the uncoated surface, using devices of known thickness such as shims, or using a coated specimen of known film thickness
• Measurement.

BS EN ISO 2808:2007 replaces BS EN ISO 2808:2001, which has been withdrawn.

Also available for paint and varnish:

BS 3900-0:2010 Methods of test for paints. Index of test methods