Lockout/Tagout is more than just putting a yellow lock on the main electrical disconnect to a machine or part of a machine. Knowing what and where to lockout something is critical.

Prior to servicing that requires Lockout/Tagout you must evaluate the potential energy that could be released while working in that area or on a specific device. There are several types of energy:

• Electrical energy to operate the device. 
• Pnuematic energy or commonly known as air that controls various devices.
• Steam that heats various devices. 
• Natural Gas that is used in compustion devices 
• Water that may be used to cool devices 
• Hydraulics that may be used to control devices
• Gravity that may play a part in something lifted off the ground.
• Thermal energy that may cause things to remain hot after the source has been turned off.

As OSHA states in their standard, the purpose of LOTO is to prevent the “unexpected" energization or start up of the machines or equipment, or release of stored energy could cause injury to employees.

Depending on the task you are performing you need to evaluate and isolate the systems and sources of energy that could cause injury