Paint specifications have been developed in the past in cooperation with all parties involved in the coating and maintenance market, to indicate the suitability of paints and related products for specified applications. In a COT (quality) specification (indicated in Dutch as KO) the main topic is the performance of products and systems with respect to durability and application (among others drying times, overcoatability, viscosity), but also requirements are set for many physical and chemical properties as elasticity, adhesion, hiding power and hardness, and, if applicable, chemical resistance, water absorption, water vapour permeability, corrosion resistance, etc.
The performance of the paint product is investigated in the quality specifications, but also various properties of the total paint system, in particular, the most important one, the durability. This can be done by accelerated weathering tests in the laboratory and/or field exposure.
Quality guarantee system
COT tests the paints or related products to the requirements of the quality specifications. The manufacturer or supplier can admit the approved product in a quality guarantee system. The product/paint system is annually controlled in a so called confirmation test to check whether the test results are the same as in the first examination. If all are the same, an updated COT certificate will be supplied to the manufacturer.
The COT certificate for paint products, sealants and plasters is distributed to indicate the minimum quality level of these products in specified applications. The user of these products is guaranteed of sufficient quality of products and systems. The producer is protected against unrealistic or irresponsible requirements of the principle.
There are about 140 quality specifications and many qualified products. There are products for wood, concrete and steel, as wood repair products, undercoats, primers, lacquers, trims, claddings, varnishes, wood stains, wall paints, (spray)plasters, sealants, etc.
The quality specifications are incorporated in the project description or working instructions for painting work of various organisations as large industrial companies, STABU, architects and housing corporations.