Control of Dangerous Energy — Lockout/Tagout

Workers are killed or seriously injured when machinery starts to operate (becomes energized) when it is supposed to be turned off. AFSCME members have been killed when trying to unjam garbage compactors. Others have burned to death or drowned when a valve was opened when it should have been closed.

These types of incidents happen most often while machinery is being repaired or maintained. Electricity is the most common type of energy used to run machinery. Hydraulic, pneumatic, mechanical, heat or chemical energy are other types of energy that are used to run equipment.

Preventing the release of dangerous energy

The two most common ways to protect workers from injuries due to the operation of machinery when the equipment is supposed to be shut off are:

• Lockout: The on/off switch or valve is set in the OFF position. A lock (key or combination lock) is placed over the device that turns on the machinery so that it stays in the OFF position until the machine is serviced and ready to be started up again. 
  
  
• Tagout: In this method, a tag is attached to the switch, circuit breaker or valve when the machinery is turned off. The purpose of the tag is to keep it from being used until the tag is removed.

Figure 6 shows a valve that is locked out and tagged out.

Figure 6

Lockout is safer than tagout. 
The lockout method should be used whenever possible! 
 

Laws to protect workers

The OSHA regulation to protect workers from hazardous energy is 29 CFR 1910.147.