OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 12 General Safety Precautions

Section 193 Tire servicing

This section is intended to prevent worker injury caused by the explosion or violent separation of parts of multi-component wheel assemblies. Blowoffs, the sudden, violent springing of tire lock rings, rims or flanges from tires being assembled, are the main hazard. Blowoffs usually happen when tires have just been mounted on their rims and are being inflated. The cause is generally incorrect positioning of tire fastenings but may also include out-of-true rims and defective component parts. Blowouts involving the sudden rupture of a tire or tube may be due to overinflation.

The employer must make sure that the tire manufacturer’s inspection and servicing requirements are followed. Truck tire servicing manuals and videos are available from most manufacturers. The manuals must be kept on hand and readily available so that all workers can access the service manuals.

Only competent workers are permitted to service, inspect, disassemble and reassemble tire and wheel assemblies. If a worker is not competent to perform this work, the worker must be under the direct supervision of a worker who is competent. All of this work must be performed according to the manufacturer’s specifications or instructions. Workers performing this work must be trained and understand how to properly inspect and safely service tire and wheel assemblies.

Tires mounted on a split-rim or locking ring wheel (see Figure 12.6) must be inflated in a safety cage as shown in Figure 12.7 or be suitably restrained to contain flying parts in the event of tire rupture or component failure. Some manufacturers recommend partial inflation in a safety cage and full inflation once the tire and wheel assembly is mounted on the vehicle axle.

Figure 12.6 Example of locking ring rim

Figure 12.7 Example of cage used to restrain split rim wheel assemblies

When inflating split rim and locking ring wheels, only a clamp-on type connector is allowed. A clamp-on type connector attaches securely to the valve stem and does not require the worker to hold it in place against the valve during inflation (see Figure 12.8). This permits the worker to inflate the tire while standing a safe distance away from the tire.

Figure 12.8 Clamp-on connector

Other types of inflation devices usually require the worker to forcibly hold them against the tire’s valve stem, requiring the worker to stand immediately next to the wheel. Such inflation devices are unacceptable because their use places the worker at risk of serious injury in the event of a blowoff or other tire failure.

When a clamp-on air connector is used to inflate a tire, the inflation hose to which it is attached must

(a) permit the use of an in-line pressure gauge – this eliminates the need for the worker to approach the tire to take a pressure reading with a pencil-type pressure gauge. The pressure gauge can be built directly into the inflation control or the control may have a check valve that permits pressures to be taken using a pencil-type pressure gauge (see Figure 12.9). The worker must be able to monitor tire pressure at a safe distance away from the tire being inflated, and

(b) be under positive pressure control by the worker filling the tire – air can only be delivered to the tire while the worker squeezes or depresses a control. The flow of air must stop immediately upon the worker releasing the control.

Figure 12.9 In-line valve and gauge

The worker is responsible for staying in a safe position while inflating the tire. Figure 12.10 shows examples of the trajectories a wheel assembly might take if it should separate. The hose should be long enough between the clamp-on connector and the in-line valve to allow the worker to stand in a safe position.

Figure 12.10 Examples of trajectories and dangerous work positions

For more information
Servicing Tires Safely
Bulletin GS003