04.1 – So what is it and why?

Lockout is:

Equipment, machine, or process made inoperable by placement of a lockout device on an energy-isolating device in accordance with an established procedure, thereby indicating that the energy-isolating device is not to be operated until removal of the lock or in accordance with an established procedure.

It’s Purpose:

To ensure a safe work condition: a state in which an energy source has been disconnected, locked, and tagged out, in accordance with established standards and tested to ensure the isolation of energy.