A hazardous energy control procedure explains how to isolate equipment from dangerous energy, prevent its unexpected release or startup, and verify it is safe before work begins. Often called a lockout/tagout (LOTO) procedure, it must be specific to the equipment and task; workers should follow their employer’s approved procedure and applicable rules, not rely on a generic checklist alone.
What the procedure controls
Hazardous energy is not limited to electricity. It includes any stored or supplied energy that could injure someone during servicing, maintenance, cleaning, or repair. Common examples include:
- Electrical energy in circuits, capacitors, batteries, or electrical equipment.
- Mechanical energy from rotating parts, flywheels, springs, or moving assemblies.
- Hydraulic or pneumatic pressure in lines, cylinders, and accumulators.
- Gravity and other potential energy, such as a raised load or elevated machine part.
- Thermal, chemical, and other process energy that can cause burns, exposure, or sudden release.
A control procedure identifies the relevant energy sources, isolation points, devices, stored-energy hazards, and verification method for a particular machine. A warning tag alone generally does not physically prevent operation, so it is not interchangeable with a lock where a lock can be used under the applicable rules.
Core steps in a hazardous energy control procedure
Exact steps vary by equipment and workplace, but a sound procedure typically follows this sequence. The employer’s written program and equipment-specific instructions take precedence over this overview.
- Prepare and notify. Identify the equipment, work scope, energy sources, affected workers, and required protective equipment. Notify affected employees before shutdown.
- Shut down normally. Use the equipment’s normal controls to stop it, following the shutdown instructions. A stop button or software command is not, by itself, an energy-isolating device.
- Isolate every source. Operate the appropriate physical energy-isolating devices, such as disconnects, valves, or blocks. Check for secondary feeds and interconnected equipment rather than assuming one switch controls everything.
- Apply locks and tags. Authorized workers apply their locks to the isolation points, using devices suited to the equipment. Tags identify the lockout and communicate the warning; they do not physically restrain an operating control.
- Release or restrain stored energy. Discharge, drain, vent, block, lower, or otherwise control residual energy as the procedure specifies. If energy can build up again, maintain monitoring or repeat verification as needed.
- Verify isolation. Confirm that the equipment cannot start or release hazardous energy using the procedure’s stated method. This may include trying normal controls after isolation and returning them to off, or using an appropriate test instrument. Electrical testing must be done by qualified personnel using suitable methods and equipment.
- Perform the work and maintain control. Keep locks in place while exposure continues. If conditions or the work scope change, stop and reassess the procedure before proceeding.
- Restore equipment safely. Inspect the area, reinstall guards, remove tools, and confirm people are clear. Each worker removes their own lock under the normal process; notify affected employees before re-energizing.
Roles, group work, and shift changes
Many workplace programs distinguish authorized employees, who apply energy controls and perform covered servicing, from affected employees, who operate or work near the equipment. Everyone who could be exposed needs to understand the hazards and the meaning of locks and tags. Training and responsibilities depend on the employer’s program and governing requirements.
For group work, the system must ensure each worker is protected, commonly by using a group lockbox or equivalent arrangement: equipment isolation keys are secured, and each exposed worker applies a personal lock to the group control. A crew member should not assume a coworker’s lock protects them unless the established group procedure explicitly provides that protection.
Shift or personnel changes require an orderly transfer of protection so that incoming workers are covered before outgoing workers remove theirs. Removing another person’s lock is not a routine shortcut; any exceptional removal must follow the employer’s documented process and applicable rules, including efforts to contact the lock owner and confirm the person is clear.
Common failures and misconceptions
- Relying on a stop button: Controls can leave power connected or allow someone else to restart the machine. Isolate at the energy source.
- Missing a secondary source: A machine may have multiple feeds, stored pressure, a battery, or energy from connected equipment. Trace all relevant sources.
- Assuming zero energy lasts: Pressure may return, capacitors may retain charge, and gravity can move a raised part. Secure and recheck as the procedure requires.
- Skipping verification: A lock shows that a control was secured; verification checks whether isolation actually worked. Both matter.
- Using a generic procedure for complex equipment: General instructions can omit machine-specific hazards. Use a clearly identified, current procedure for the equipment and task.
- Confusing routine operation with servicing: Some minor servicing during normal production may be treated differently under specific regulatory conditions, but the exception is limited. Do not assume that brief work or a quick adjustment is automatically exempt.
Hazardous energy control procedure template
Use this blank worksheet to organize information for a qualified review. It is not a substitute for a site-approved program, equipment-specific assessment, training, or applicable regulatory requirements. Add pages where needed and verify every isolation point on the actual equipment.
| Field | Procedure details |
|---|---|
| Equipment name and identification | |
| Work covered and location | |
| Authorized person or role | |
| Affected employees to notify | |
| Energy source and hazard | |
| Isolation point and device | |
| Lock/tag method | |
| Stored-energy release or restraint | |
| Verification method and result | |
| Restoration and notification steps | |
| Procedure owner and review date |
Sample — fictional example only: Equipment: Northline Training Press, unit T-04. Work: inspect a guarded feed roller. Sources: electrical supply and gravity from the raised roller. Isolation: open the identified disconnect and secure the roller with the specified mechanical block. Verify: follow the equipment procedure’s restart test and confirm the roller remains restrained. This sample is not an approved procedure and should not be copied for real equipment.
Frequently Asked Questions
Is lockout/tagout the same as a hazardous energy control procedure?
A hazardous energy control procedure is the documented method for controlling dangerous energy. Lockout/tagout is a common part of that method, covering the application of locks and tags to energy-isolating devices. A complete procedure also addresses shutdown, stored energy, verification, and safe restoration.
Can a tag replace a lock?
Not automatically. A tag warns people but does not physically prevent operation. Whether tag-only protection is permitted, and what additional measures are required, depends on the applicable rules and the employer’s program. Workers should follow the approved procedure rather than substitute a tag for a required lock.
Who removes a worker’s lock?
Normally, the worker who applied a personal lock removes it. If that person is unavailable, the employer’s documented exceptional-removal process must be followed, including safeguards to establish that the worker is not exposed and to notify them as required.
Does turning off the machine make it safe to service?
No. A normal control may stop motion without disconnecting energy, and residual pressure, electricity, heat, or gravity may remain. Use the equipment-specific isolation procedure and verify the safe condition before work begins.
Does every machine need its own procedure?
Procedures need to identify the equipment and its energy-control steps clearly enough for workers to apply them safely. Some similar equipment may qualify for a documented group or standard procedure under applicable requirements, but a generic checklist that leaves isolation points unclear is not adequate guidance.