The employer must write down, for each machine or type of equipment, how to control its energy. This is the energy control procedure. It is the heart of a LOTO program, and authorized employees must follow it every time.
What a procedure must contain
Under 29 CFR 1910.147(c)(4), a procedure must clearly and specifically set out:
- the intended use of the procedure;
- the steps for shutting down, isolating, blocking and securing the equipment;
- the steps for placing, removing and transferring lockout or tagout devices, and who is responsible for them;
- the requirements for testing the equipment to verify that the controls work.
The procedure must be documented. The standard allows an employer to skip the written document only for equipment where all of a strict list of conditions is met. They include: there is a single, readily identified energy source, no stored energy can build up, the isolating device is single and lockable, and there has been no history of injury from unexpected reenergization. Most machines do not qualify.
The six steps
When an authorized employee controls energy, the standard's sequence is as follows.
- Preparation. Learn the type and amount of energy, its hazards and how to control it. Read the procedure for that machine first.
- Shutdown. Turn the machine off using its normal stopping method. Do it in an orderly way so that stopping does not create a new hazard.
- Isolation. Find and operate all the energy isolating devices that separate the machine from every energy source.
- Apply the lockout or tagout devices. Put the devices on each isolating device. A lock holds the device in the safe or "off" position. A tag goes at the same point where a lock would be attached.
- Deal with stored energy. Relieve, disconnect, restrain or otherwise make safe any stored or residual energy. Bleed pressure, lower raised parts, block moving parts, discharge capacitors. If stored energy can build up again to a hazardous level, keep checking until the work is done.
- Verify. Before work starts, confirm that the machine is isolated and deenergized. This often means trying to start it from its normal controls, with everyone clear. Then return the controls to "off."
Why verification matters
A lock on the wrong switch gives a false sense of safety. Machines can have more than one power source, and some valves leak. Testing is the only way to know the isolation worked. Verification is a separate step. It is not optional and must never be skipped to save time.
Do not use these as shortcuts
- Do not rely on a stop button or a guard.
- Do not assume a machine is dead because it has stopped moving.
- Do not put a lock on a device the procedure does not name.
- Do not use a tag where the procedure requires a lock.
- Do not begin work before verification is done.
Appendix A
OSHA also publishes a sample "minimal" lockout procedure in an appendix to the standard. It is a model for simple equipment with a single source of energy. Employers still need a procedure that fits their own machine.
What to remember
- Each procedure states use, steps, device handling and testing.
- The sequence is prepare, shut down, isolate, apply, release stored energy, verify.
- Verification proves that the isolation worked.
- Stored energy needs its own step.
- An authorized employee follows the machine's own written procedure every time.