Stored energy has many forms, including pressurised gases and liquids, stored mechanical or electrical energy, as well as gravitational energy.

The impacts of not identifying and releasing stored energy before conducting work can be fatal. Examples of inadvertent release of energy include:

• A steam valve automatically turning on burning workers repairing piping downstream
• A jammed conveyor system suddenly releasing, crushing a worker trying to clear the jam
• Hot working around pressurised hoses

In the event that stored energy cannot be released, the risk assessment must identify the additional controls required to ensure the safety of personnel.

The isolation must be planned so that all potentially hazardous stored energy or residual energy must be relieved, disconnected, restrained, or otherwise rendered safe before work starts. The isolation effectiveness must ensure stored energy cannot build up to a hazardous level during the isolation.

There are four basic steps to controlling the risk of the unexpected release of stored energy: