SAFETY MODEL STAGE 3—CONTrOLLING HAZArDS: SAFE WOrK ENVIrONMENT
Lock-out/tag-out is an essential safety procedure that protects workers from injury while working on or near electrical circuits and equipment. Lock-out involves applying a physical lock to the power source(s) of circuits and equipment after they have been shut off and de-energized. The source is then tagged out with an easy-to-read tag that alerts other workers in the area that a lock has been applied.
n addition to protecting workers from electri- cal hazards, lock-out/tag-out prevents contact with operating equipment parts: blades, gears, shafts, presses, etc. I
A worker was replacing a V-belt on a dust collector blowe . Before beginning work, he shut down the unit at the local switch. Howeve , an operator in the control room restarted the unit using a remote switch. The worker s hand was caught between the pulley and belts of the blowe , resulting in cuts and a fractured finge .
When performing lock-out/tag-out on machiner , you must always lock out and tag out ALL energy sources leading to the machinery.
Also, lock-out/tag-out prevents the unexpected release of hazardous gases, fluids, or solid matter in areas where workers are present.
An employee was cutting into a metal pipe using a blowtorch. Diesel fuel was mistakenly discharged into the line and was ignited by his torch. The work- er burned to death at the scene.
All valves along the line should have been locked out, blanked out, and tagged out to prevent the release of fuel. Blanking is the process of inserting a metal disk into the space between two pipe flang- es. The disk, or blank, is then bolted in place to pre- vent passage of liquids or gases through the pipe.
When performing lock-out/tag-out on circuits and equipment, you can use the checklist below. ✔ Identify all sources of electrical energy for the equipment or circuits in question. ✔ Disable backup energy sources such as gener- ators and batteries. ✔ Identify all shut-offs for each energy source. ✔ Notify all personnel that equipment and circuitry must be shut off, locked out, and tagged out. (Simply turning a switch off is NOT enough.) ✔ Shut off energy sources and lock switchgear in the OFF position. Each worker should apply his or her individual lock. Do not give your key to anyone. ✔ Test equipment and circuitry to make sure they are de-energized. This must be done by a qualified person.* ✔ Deplete stored energy (for example, in capaci- tors) by bleeding, blocking, grounding, etc. ✔ Apply a tag to alert other workers that an energy source or piece of equipment has been locked out. ✔ Make sure everyone is safe and accounted for before equipment and circuits are unlocked and turned back on. Note that only a qualified person may determine when it is safe to re-energize circuits.
*OSHA defines a “qualified person” as someone who has received mandated training on the hazards and on the construction and operation of equipment involved in a task.