Lock Out Hazardous Energy

Safety Talk

Just because a piece of equipment is standing silent and motionless doesn’t mean it’s safe. What you don’t see or hear could kill or maim you.

You must take steps to prevent equipment from becoming energized while it is being worked on. The energy can be pneumatic, electrical, mechanical, hydraulic, chemical or thermal. There can be other sources as well — gravity, for example.

The best way to prevent release of hazardous energy is with a lockout/tagout procedure.
Machines and equipment might be connected directly to an energy source or they might contain “stored energy.” This energy waiting to be released can be electrical, such as in generators, hydraulic or mechanical.

Employees doing service or maintenance must be trained to ensure they know, understand and follow a written procedure for controlling hazardous energy.

That procedure should include:

• Use of lockout devices to render the machinery or equipment inoperable or to isolate an energy source.
• Use of tags or other warning devices to indicate that the equipment being controlled must not be used until the tagout device is removed.
• An effective tagout program for machines or equipment that are not capable of being locked out. Tagout should be used instead of lockout devices only if it provides protection equal to that of the lockout program.

Only those lockout/tagout devices that are authorized for a particular piece of machinery should be used. The lockout/tagout should be done only by authorized personnel, who should be identified on the devices.

An energy-isolating device is considered capable of being locked out if it:

• Is designed with a hasp or other means by which a lock can be attached
• Has a locking mechanism built into it
• Can be locked without dismantling, rebuilding or replacing the energy-isolating device or permanently altering its energy control capability

An energy-isolating device is one that physically prevents the transmission or release of energy. It could be:

• A manually-operated electrical circuit breaker
• A disconnect switch
• A manually-operated switch that can disconnect the conductors of a circuit from all underground supply conductors
• A line valve
• Any similar device that can block or isolate energy. (Push buttons, selector switches and other control circuit-type devices are not energy-isolating devices.)

Conducting a lockout procedure takes training, supervision and documentation. Make sure you know what you are doing if you are assigned to do a lockout.