OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 15 Managing the Control of Hazardous Energy


In this Part, hazardous energy is defined as

“electrical, mechanical, hydraulic, pneumatic, chemical, nuclear, thermal, gravitational, or any other form of energy that could cause injury due to the unintended motion energizing, start-up, or release of such stored or residual energy in machinery, equipment, piping, pipelines, or process systems”

Workers servicing, repairing, testing, adjusting or inspecting machinery, equipment, powered mobile equipment, piping, pipelines, or process systems may be injured if there is unintentional movement, the equipment is unexpectedly energized, unexpectedly started up, or releases stored energy. A detailed, comprehensive hazard assessment can identify the type and location of hazardous energy sources. Part 2 of the OHS Code requires that a hazard assessment be conducted before the work activities listed above are performed on machines, equipment, piping, pipelines, or process systems.

If there is a hazard to workers, control of hazardous energy involves the following steps.

(1) Isolating the location at which work is to be carried out from sources of energy. This is accomplished by shutting off the machine, equipment, or process systems, or regulating flow in piping or pipelines and by operating or installing a mechanical device (energy-isolating device) that relieves, blocks, bleeds, restrains or otherwise physically prevents or controls the transmission or release of energy for each energy source that may affect the work area.

(2) Verifying that the work area is isolated from all energy sources and the machinery, equipment, piping or process system is inoperable. This requires testing to verify that energy from each source cannot reach the work area. In the case of interlocked systems, the interlock sequence should be fully completed or overridden.

(3) “Locking” the isolation by ensuring that the energy-isolating device and all relevant components are physically secured to prevent the release of energy that could cause inadvertent movement or activation. Access to the securing device must be properly managed.

(4) Once the work activity has been completed, returning the system to operation by removing any securing devices, verifying that no worker is in danger, and releasing the energy-isolating device.