Is composite decking slippery when wet?

Workplace (Health, Safety and Welfare) Regulations 1992 require floors to be suitable, in good condition and free from obstructions, so that people are able to move about safely.

The Health & Safety Executive (HSE) guidance has determined that the most reliable and robust test method is the Pendulum Test. This is the method checked when they are looking at enforcement action and local authority advice.

No, even when wet, composite decking has a low risk for slip potential. Keeping your deck clear of mildew and algal growth will help preserve the non-slip properties.

The pendulum method (BS 7976: Parts 1-3, 2002) works by replicating a heel striking a surface in a dynamic way, as shown in the diagram below. The test is designed to replicate a pedestrian heel strike, the point at which most slips occur. When a pedestrian heel strikes a wet floor a fluid film is created between them, which can cause the slip (90% of slips occur on wet floors). The test therefore works in wet conditions because it generates a similar fluid film between the slider and the floor. (The heel strike is point 2).

The result (which is at point 3) is called the Coefficient of Friction (CoF), a direct measure of the slip resistance of a floor.

The flooring is tested in three directions (with any grain, 45 degrees from grain, 90 degrees from grain) and the mean average of the CoFs found used as the overall CoF.

The slider referred to in test data is also important; two sliders are commonly used, one for shod pedestrians and one for barefoot.

Any CoF value over 36 is regarded as “low slip” on flat surfaces – meaning the probability of one fall per million footfalls. Note that the Pendulum Test Value and the probability of a slip on a floor is not a linear scale: a drop of just two PTV from 36 to 34 will reduce the ability of the floor to resist slip by 10 times.

The value found relates to pedestrians walking in a straight line on a level surface. For other activities or inclined surfaces, the table figures will change, e.g. the value of CoF is reduced by 1.76 for every 1 degree of slope.

This value will be recorded on dry and wet surfaces.

Flooring is often given an R-rating. This is a value from 9 (very slippery) to R13 (not slippery) and is determined by the point at which people generally fall when taking small forwards and backwards steps on an oil covered flooring sample that is having its ramp (angle of incline) gradually increased.

Because the test gives a range, requires boots that people don’t generally wear and uses oil HSE has determined to prefer the CoF pendulum method.

All our flooring contains a CoF rating, and for convenience and comparison an R-value is given for porcelain as this is a value some people in the industry are still familiar with.

The approximate conversions between the two rating systems is given in the following table:

Hyperion composite decking is anti-slip and skid-resistant, with a low risk for slip potential.

The following slip test results for Hyperion Decking composite deck boards are as tested to the BS7976-2: 2002 standard (Pendulum Test – 4S Rubber). The 4S Rubber slider is used to imitate everyday pedestrian shoes (not necessarily anti-slip safety footwear), so the slip resistance would represent someone wearing shoes and not barefoot.

The results were achieved by an independent testing facility and are from samples of clean boards picked at random. Because of the variable nature of the natural and recycled materials used in the manufacture of Hyperion Decking, slip resistance results may vary slightly from batch to batch.

It is also worth noting that keeping your decking surface clean and clear of mildew and algal growth will help to retain its non-slip properties.