The Dutch Floor Testing Company conducts surface roughness measurements or slip resistance measurements of among other things floors in showers and bathrooms. Upon request we will issue a certificate if the standard has been met.

Floors may cause nasty falls or slips with far-reaching medical and financial consequences. Often this is due to the fact that floors are too slippery, too rough, or they are wet or soiled.
If you suspect that your floor is not safe, or if you want to be absolutely certain that your floor is safe enough: The Dutch Floor Testing Company measures the surface roughness or slip resistance of almost all floors.

NEN EN 7909:2015 
Walkable surfaces. 
This is the most common standard in the Netherlands for walkable floors, both dry and wet.

Measuring instrument: GMG 200
Slider plate: mix of leather / rubber and rubber only.

Measurements are carried out both wet and dry.
Per measuring series 5 times, of which the last 3 measurements are valid. The average of the last 3 measurements of a series is the friction ratio.
Measurements are conducted with 2 different sliders: a mix of leather/rubber and rubber only. The slider with a mix of leather/rubber is only measured dry, the rubber only slider is measured both dry and wet.

Per measuring location this therefore amounts to 15 measurements, 9 of which are being recorded.

Classification application floor dry: NEN 7909-2015
The minimum requirement is 0.3 μ. (All sliders measured dry)
Classification application floor (regularly) wet: NEN 7909-2015
The minimum requirement is 0.4 μ. (All sliders).
Classification application floor wet at swimming pool: NEN 7909-2015
The minimum requirement is 0.45 μ. (All sliders).

Remark: NEN 7909:2015
This standard does not apply to the durability of the slip resistance of walkable surfaces.
Meeting the slip resistance requirement reduces the risk of slipping to an acceptable level, however, it offers no guarantee for the prevention of accidents.
· Other factors that have an effect are shoes, contaminations, environmental factors, motor skills, a person’s power of observation.
· The use and contamination of the surface may influence its slip resistance.

Dry application:
Situation, where a contamination with a fluid occurs only in case of cleaning activities or of an emergency.

Wet application:
Situation where a contamination with a fluid may occur also besides cleaning activities and an emergency.

Based on the measured slip resistance and the specific application of the floor, a floor may be judged to be either sufficiently slip resistant or insufficiently slip resistant.
The measured slip resistance is “sufficiently” or “insufficiently” slip resistant.