BS 3900- A16 discusses test methods for paints. The aim of BS 3900-A is to provide the best industrial practice that helps in assessing the characteristics of paint.
BS 3900- A16 describes a method for assessing the natural spreading rate of application of a product (in terms of area per wet film mass or area per wet film volume, as appropriate) when applied by brush to test panels.
Note: The method is not suitable for products that contain highly volatile solvents.
BS 3900- A16 on liquid paints is useful for:
The 'natural spreading rate' is tied up with the application properties of the paint and reflects how far a paint would be spread by someone simply painting by 'feel'. The 'easier' a paint is to apply, the further it will be spread and the thinner the resulting film will be.
BS 3900- A16 describes a laboratory method for determining the natural spreading rate of paints. BS 3900- A16 covers the principle of the apparatus, procedure, and test report. This can help in assessing the performance requirements of paints.