What causes us to slip or lose our footing on wet pavement or grass? A loss of friction between your boots and the wet ground surface. Friction is the force exerted by a surface when an object moves (or makes an effort to move) across it, for example, tires on asphalt.
The friction between your feet and a walking or working surface decreases when the surface becomes wet or covered with other material like mud, oil, grease, snow or ice. The coefficient of friction is the force that resists the motion of one body in relation to another body in contact with it.
Using the following coefficients for reference, you can see that friction is reduced by 71% on dry steel vs. wet steel (e.g. equipment steps or trailers).
| Dry asphalt = 0.9 | Ice = 0.1 |
| Clean dry steel = 0.7 | Wet steel = 0.1 – 0.2 |
| Dry wood = 0.5 | Ice on wood = .05 |
| Wet wood = 0.2 | Ice on steel = .03 |
When a surface becomes wet or covered with mud or other materials, you must adjust your behavior. You need to concentrate and change your frame of mind. You cannot move at the same rate you did when it was dry.
- Clear obstructions and keep travel paths free of debris and materials.
- Keep your hands out for balance and concentrate on the surface you are walking on.
- Clean a wet trailer’s surface before loading and unloading equipment.
- Be aware of surface conditions when entering or exiting a vehicle or equipment.
- Concentrate when climbing in or out of a truck bed.
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