Work Permits and Isolation of Equipment

Permits to Work

A safe system is required for all work activities, but particularly for hazardous maintenance activities. A large proportion of serious and fatal accidents occur during maintenance operations. A permit to work system is a formal procedure to ensure that the system of work is properly planned and implemented for jobs which have a significant risk. Permits are most often required for maintenance work where normal safeguards cannot be used, or where new hazards are introduced by the work. They should not generally be used for low-risk operations, as this tends to devalue the system.

Permits to work are required whenever there is a significant risk to safety and health during an operation, and where precise preparation of the site or plant and clear, unambiguous communications of procedures is needed to control the risk.

A permit to work should not be confused with giving someone permission to work on site; nor is it an excuse to carry out a task without eliminating hazards or minimising risks. Issuing a permit does not, by itself, make a task safe. That can only be achieved by the diligence of those preparing, supervising and carrying out the work. The system does, however, provide a formal procedure to determine, systematically, what precautions are required, how this should be communicated, recorded and monitored and how work should be authorised. In some high-risk situations, simple systems of work such as isolation or locking off procedures are sufficient by themselves to ensure safety. Such generally appropriate when there is only a single source of risk, which can be eliminated by, for example, removing a fuse and locking off an electrical isolator switch. In more complicated cases, for example, where there are several sources of risk or where the risk is more severe, such as with high voltage systems, or where complex procedures are needed before it is safe to start work, a permit to work is usually appropriate. The aim of the permit to work system is to ensure that the task is carried out in accordance with the carefully considered conditions specified in a permit drawn up and independently verified by competent individuals. As well as setting out the steps which must be taken before and during the task, permits should state any conditions to be met after the work is completed, i.e., the procedure for handing back the plant or area in a safe condition for normal operations.

Quarry Safety Series - Working on Fixed Plant - Safe Systems of Work


Quarry Safety Series - Working on Fixed Plant - Unsafe Systems of Work

Isolation of Equipment

The isolation process is also known in industry as 'lockout / Tagout' and is used to isolate machinery and equipment from its energy source. It is important to ensure the isolation of any unsafe machinery/equipment from potential uncontrolled energy sources during repair, service or maintenance work. Isolation can be used as a standalone method of ensuring the safety of maintenance staff carrying out maintenance operations at a quarry where permits to work are not necessary or as part of a Work Permits requirements. The basic rules are that there should be isolation from the power source (usually, but not exclusively, electrical energy), the isolator should be locked in position (for example by a padlock), and a sign should be used to indicate that maintenance work is in progress. Any stored energy (hydraulic or pneumatic power, for instance) should also be dissipated before the work starts. Before entering or working on the equipment, it is essential that the effectiveness of the isolation is verified by a suitably competent person.