Lockout/Tagout, Materials Handling and Machine Guarding
How hazardous energy is controlled during servicing, how materials, trucks, cranes and tyres are handled safely, and how machines are guarded at the point of operation, the power transmission and the other moving parts.
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5.1 Lockout/Tagout
When a machine is repaired, adjusted or cleaned, a sudden start up or a release of stored energy can kill. The OSHA Control of Hazardous Energy standard, called lockout/tagout, sets the rules for stopping this.
Key terms
| Term | Meaning |
|---|---|
| Authorised employee | A person who locks out or tags out machines or equipment to service or maintain them. |
| Affected employee | A person who uses the machine on which servicing is done, or works in the area. |
| Energised | Connected to an energy source, or holding stored or residual energy. |
| Servicing and maintenance | Constructing, installing, setting up, adjusting, inspecting, modifying, maintaining or servicing, including lubricating, cleaning or clearing jams, and tool changes, where people could be exposed to unexpected start up or release of energy. |
| Normal production operations | Using a machine for its intended production function. |
Lockout and tagout
- Lockout blocks the flow of energy from a source and keeps it blocked. Lockout devices, such as locks, blank flanges and bolted slip blinds, use positive means to hold an energy isolating device in a safe position.
- Tagout is a warning. A tag fastened to an energy isolating device says that the equipment must not be operated until the tag is removed. It is not a physical restraint.
Lockout/tagout applies to any machine whose unexpected start up could harm people while it is repaired, replaced, renovated, modified or adjusted. Only authorised employees apply the devices.
Devices
Lockout and tagout devices must be durable and clearly identifiable, used only for energy control, standardised by colour, shape or size, and each must show clearly who fitted it.
The sequence
- Prepare for shutdown. Find out what energy sources the machine has and what hazards they carry. Tell affected employees.
- Shut down the machine in the normal way.
- Isolate the machine from every energy source.
- Apply the lockout or tagout device so that it holds the isolating device in the safe or off position. A tag must be placed as close to the device as possible, where it is clearly seen.
- Release stored energy. Relieve, disconnect, restrain or make safe all stored or residual energy, such as springs, pressure, gravity and capacitors.
- Verify. The authorised employee checks that the equipment is shut down, isolated and de-energised. Try to start it, then return the controls to off.
Before the equipment is released for use, inspect it, make sure that everyone is clear of the machine, and only then remove the devices. The person who fitted a device removes it.
The energy control program
An energy control program has three parts:
- Procedures that set out the steps for an authorised employee to carry out lockout or tagout.
- Periodic inspections, at least once a year, to make sure that procedures are followed.
- Training and retraining for all employees. The employer must train authorised employees, affected employees and other employees on the purpose and function of the program, so that each has the knowledge and skill for the safe application, use and removal of the controls.
A study aid, not published or endorsed by IOSH or OSHA. Laws and limits differ between countries.