Tyre removal, replacement and inflation
Tyre removal, replacement and inflation should only be tackled by competent staff. The main hazards which can arise include:
- manual handling injuries, which account for nearly a half of all tyre-related incidents reported;
- tool-related injuries (which make up a quarter of incidents), particularly from handtools such as tyre levers; and
- compressed-air accidents eg from a ruptured or burst tyre or violent separation of the component parts of the wheel. These accidents tend to result in serious injuries, including fatalities.
Safety during tyre inflation
Inflated tyres contain a large amount of stored energy, which varies according to the inflation pressure and the surface area of the tyre (eg the sidewall of a typical commercial vehicle tyre has to withstand over 34 tonnes of force from compressed air before additional carriage weight is taken into account).
If the tyre fails, an explosive force can be released at an angle of up to 45 degrees from the rupture (which is often, but not always, the face of the sidewall). This has resulted in numerous fatalities over the years. It is crucial that the airline hose between the clip-on chuck and the pressure gauge/control is long enough to allow the operator to stand outside the likely trajectory of any explosion during inflation. This will vary depending on the size of the tyre and its positioning.
Car tyres generally contain less energy than truck tyres and their size and profile make them less likely to fail catastrophically. Sensible precautions are still required, but a restraining device such as a safety cage is not normally necessary.
Light commercial tyres are now commonly found with pressures around 70psi, which may be sufficient to cause serious injury. If so, use enhanced safety measures such as those required for conventional truck/bus tyres. When inflating above 15psi this will include using a restraint such as:
Airlines should have quick-release couplings at both ends to allow the tyre to be deflated from outside the likely explosion trajectory if a fault (eg a potential 'zipper' failure of the sidewall) is detected. The valve connector should not require the operator to hold it place.
The pressure gauge/control valve should never be jammed in the open position, nor should 'unrestricted' airlines (ie without a gauge or pressure control device) be used to inflate any tyre. For bead-seating of large commercial tyres, removing the valve core allows faster inflation without using excessive pressure. Split rim wheels are now uncommon but they may be found on older vehicles and in some specialist applications. Unfamiliarity can increase the risk of a catastrophic failure so additional training will probably be required. Use only metal restraints of adequate strength.
The following YouTube video demonstrates the power of a tyre explosion resulting from inflating a damaged tyre.
Very large tyres such as those found in agriculture, quarries etc may be too big to fit into a restraint. Safe systems of work will need to be devised to ensure:
- the wheel is restrained;
- the effects of any explosion are contained safely; and
- everyone stays outside the likely explosion trajectory