You are here：Home > news2025
Expression of results in EN ISO 11998 (Paints and varnishes-Determination ofwet-scrub resistance and cleanabilityof coatings)
Posted Date:2025/11/4
9 Expression of results
9.1 Calculation of the loss in coating mass per unit area
9.1.1 Area traversed by the scrub pad Calculate the area A, in square metres, traversed by the scrub pad using Equation (1):
where
S is the scrub length, in millimetres (see 3.3);
W is the scrub width, in millimetres.
9.1.2 Loss in coating mass per unit area
Calculate the loss in coating mass per unit area L, in grams per square metre, using Equation (2):
where
A is the area, in square metres, traversed;
m1, is the initial mass, in grams, of the test panel and dry coating film;
m2 is the mass, in grams, of the test panel and dry coating film after 200 scrub cycles.
9.2 Calculation of mean loss in film thickness
Calculate the mean loss in dry-film thickness Ldt, in micrometres, using Equation (3):
where
ρdf is the dry-film density, in grams per cubic centimetre, of the coating, determined in accordance with Annex A:
A, m1, m2 and L are as defined in 9.1.1 and 9.1.2.
9.3 Assessment of wet-scrub resistance
The mean loss in film thickness is determined in micrometres, This value is compared with the specified maximum loss in dry-film thickness to rate the coating (see e.g. EN 13300).
9.4 Assessment of cleanability
When no more than the specified film thickness is removed, there shall be no discernible visual difference between the areas where soiling agents were applied and the scrubbed area on a duplicate panel or on the other half of the same panel.
If the soiling agent is not removed totally, the coating can be rated visually in cleanability classes in accordance with another suitable standard.