What is a lockout/tagout procedure?
(LOTO) is a technique used to prevent energy from being released during the servicing of equipment. The procedure is executed in several steps in which an authorized employee ensures that equipment is properly shut down and any potentially dangerous stored energy is isolated and released prior to maintenance.
Lock Out and Tag Out Circuits and Equipment Create a safe work environment by locking out and tagging out circuits and machines. Before working on a circuit, you must turn off the power supply. Once the circuit has been shut off and de-energized, lock out the switchgear to the circuit so the power cannot be turned back on inadvertently. Then, tag out the circuit with an easy-to-see sign or label that lets everyone know that you are working on the circuit. If you are working on or near machinery, you must lock out and tag out the machinery to prevent startup. Before you begin work, you must test the circuit to make sure it is de-energized. Every workplace should have an energy control program in place, with LOTO safety being one part of that program. An energy control program includes established procedures for using locks and tags; the locks and tags themselves; training workers on hazards of hazardous energy and lockout/tagout procedures, policies, and equipment; and periodic reviews and inspections of the system (at least annually).
The OSHA General Industry standard that covers all this is 1910.147, The Control of Hazardous Energy (Lockout/Tagout) . OSHA has also prepared this great list of resources related to hazardous energy control.