When using elements of structural glass as a walk on floor elements safety and anti-slip properties of the floor materials should be a consideration.
The slip resistance of floor materials can be tested in a number of different ways under various British and European testing methods, however, the HSE and the UK Slip Resistance Group favour the Pendulum Test Method as detailed under BS:7976.
The test involves a swinging mechanism that passes an imitation heel, normally made of rubber, over the surface of the structural glass in an even sweeping motion. The friction that the ‘heel’ encounters will slow down the swing and a measurable pendulum test value (PTV) can be calculated.
Slip Resistance testing should be carried out in both wet and dry conditions to get a true measure of the slip resistance of the surface.
All flooring should look to achieve a PTV of more than 36 in both wet and dry conditions. Anything lower than this would be considered a high slip risk.
A PTV of 0-24 has a high slip resistance, 25-35 is a moderate slip resistance, 36+ is a low slip resistance and 75+ is an extremely low slip resistance.
A full sandblasted finish to a structural glass floor will generally achieve a PTV of 57 in wet conditions for an acceptable anti slip finish to the walk on glass. Other sandblasted patterns will need to be tested on site for an accurate PTV.
PTV's vs R Values
You also may have seen an R value be used to denote the slip resistance of a floor. An R value is calculated using a different testing method (the Ramp Test method). The surface is fixed to a ramp and raised. A human test subject then walks back and forth over the surface until they slip. A computer then tells you what the slip resistance is in an R value. This test method is very expensive and not used widely. However the conversion chart below shows you the R value to PTV.
|R9 to R13 Ratings||PTV on Horizontal Surface||PTV at 5 degree slope||Slip Characteristics|
|R9 (there are no values below this)||11 to 18||2 to 9||VERY POOR|
Slip injuries certain to occur
|R10||18 to 34||9 to 25||POOR|
Slip injuries likely to occur
|R11||34 to 51||25 to 42||BETTER|
Will adhere to most slip resistant requirements
|R12||51 to 70||42 to 61||GOOD|
Minimum recommended for high traffic areas
Good for slopes and high traffic areas