Reduce the risk of slips on ice, frost and snow

Thomas Carroll Management Services Erisk Bulletin issue 1 2010

13th January 2010

Ice, frost and snow

To reduce the risk of slips on ice, frost or snow, you need to assess the risk and put in a system to manage it.

1. Identify the outdoor areas used by pedestrians most likely to be affected by ice, for example:- building entrances, car parks, pedestrian walkways, shortcuts, sloped areas and areas constantly in the shade or wet.

2. Monitor the temperature, as prevention is key!
- You need to take action whenever freezing temperatures are forecast.
- There are also smart signs on the market, available to buy at low cost, which display warning messages at 5 degrees and below.

3. Put a procedure in place to prevent an icy surface forming and/or keep pedestrians off the slippery surface.

- Use grit (see below for more detail) or similar, on areas prone to be slippery in frosty, icy conditions.
- Consider covering walkways e.g. by an arbour high enough for people to walk through, or use an insulating material on smaller areas overnight.
- Divert pedestrians to less slippery walkways and barrier off existing ones.

4. If warning cones are used, remember to remove them once the hazard has passed or they will eventually be ignored.

Gritting - the pros and cons

The most common method used to de-ice floors is gritting as it is relatively cheap, quick to apply and easy to spread. Rock salt (plain and treated) is the most commonly used 'grit'. It is the substance used on public roads by the highways authority.

Salt can stop ice forming and cause existing ice or snow to melt. It is most effective when it is ground down, but this will take far longer on pedestrian areas than on roads.

No tests have been carried out on how much grit to use. As a guide, on roads a rate of approximately 10-15gms/m2 for precautionary salting and 20-40gms/m2 during ice and snow conditions is recommended.

Gritting should be carried out when frost, ice or snow is forecast or when walkways are likely to be damp or wet and the floor temperatures are at, or below freezing. The best times are early in evening before the frost settles and/or early in the morning before employees arrive. Salt doesn't work instantly; it needs sufficient time to dissolve into the moisture on the floor.

If you grit when it is raining heavily the salt will be washed away, causing a problem if the rain then turns to snow. Compacted snow, which turns to ice, is difficult to treat effectively with grit. Be aware that 'dawn frost' can occur on dry surfaces, when early morning dew forms and freezes on impact with the cold surface. It can be difficult to predict when or where this condition will occur.

Bags of rock salt can be purchased from most large builders merchants at an average cost of £4.00 for a 25kg bag.