There are many details to the lockout/tagout standard, all of which are important to the life and safety of personnel working in the area of energized equipment/machinery. To help you understand how to control all potential energy sources, OSHA offers an excellent free booklet titled Control of Hazardous Energy (Lockout/Tagout), OSHA publication 3120. Visit to obtain a copy.

OSHA’s lockout/tagout regulation, found at 29 CFR 1910.147, is a standard we all can live with. The regulation covers the servicing or maintenance of machines or equipment in which the unexpected release of stored energy or equipment start-up could injure workers. The name of the standard — Control of Hazardous Energy (lockout/tagout) — describes what the regulation actually requires.

A fatal accident illustrates the importance of this regulation: A contractor crew was scheduled to work on a high-pressure steam system one Saturday morning. Friday night, representatives of the contractor went to the worksite to size up the job. It was agreed the owner’s personnel would bleed down the steam line so that the system would be ready to be worked on Saturday morning. After the contractor crew left, the owner’s personnel rotated off shift. On Saturday, the contractor’s work crew arrived to complete the scheduled work on the steam system assuming the line was bled down to eliminate any temperature or pressure hazards. Without checking temperature or pressure, they began to separate a flange. One worker was scalded over 90 percent of his body. That was about 9:00 a.m. Saturday morning. Less than 48 hours later the worker died of the burns, leaving a widow and teenage son.

Let’s go back

Let’s go back to Saturday morning at 8:30 a.m. The contractor work crew arrives on site. Not seeing any locks or tags on the appropriate piping and valves, they ask the owner’s weekend crew if the high-pressure steam system is safe to work on. Everyone agrees it is not. The contractor’s crew, working with plant personnel, isolates the piping and valves to be worked on. Critical valves are closed and locked in the closed position. There is only one key to each lock; contractor personnel who will be working on the steam line keep the keys in their possession. Tags are attached to each lock, identifying who attached the locks. The owner’s personnel and other workers in the area know the steam system is out of service and who has taken it out of service. The affected sections of the steam line are bled down, in accordance with the owner’s procedures.

The contractor employees have used less than $100 of equipment and taken about one hour at overtime pay. At the completion of the job, the contractor, working with the owner’s personnel, re-energizes the system. Work continues.

In our re-creation of the job, the second time cost more and took longer. On the other hand, when you consider the cost of flowers at the funeral, the cost was actually less. People, owner and contractor took more than one hour off work to go to the funeral. So the total time of the job in our re-creation was less. And in the local youth softball league, one teenage boy was without a father who could’ve spent time with him practicing hitting and fielding. It’s hard to put a financial value on that time.

Back to basics

Knowing and following the OSHA standard may save a worker’s life someday, and can certainly prevent serious injury. There are three basic requirements to the lockout/tagout standard:

  • Establish energy-control procedures for removing the energy supply from machines and for putting appropriate lockout or tagout devices on the energy-isolating devices to prevent unexpected (and unauthorized) re-energizing of the equipment. If necessary, this procedure must address stored or potential re-accumulated energy.
  • Train employees on the energy-control programs, including the safe application, use and removal of energy controls.
  • Inspect these procedures periodically (at least once each year) to ensure that they are being followed and are effective in preventing employee exposure to hazardous energy.

    Get de-energized

    The standard addresses energy, in any of its forms. If there is electrical, mechanical, pneumatic, steam or hydraulic operated equipment or machinery to be serviced, the workers who will be maintaining or servicing it must know how to turn the equipment off and release the stored energy. There are six steps to de-energizing and securing equipment:

    1) Prepare the equipment and surrounding area for the shutdown.
    2) Shut down the equipment. Make sure any fail-safe or feedback loops that may provide an alternate energy source are also shut down.
    3) Disconnect or isolate the equipment from the energy source(s) — not some, but ALL sources of energy.
    4) Apply the lockout or tagout device(s) to the energy-isolating devices.
    5) Release, restrain or otherwise render safe ALL potential hazardous stored or residual energy. If it is possible for hazardous energy to re-accumulate, regularly verify during servicing or maintenance that this energy has not re-accumulated to hazardous levels.
    6) Verify the isolation and de-energizing of the equipment.

    Exceptions to the rule

    Are there exceptions to the lockout/tagout standard? Yes. An employer does not need a lockout or tagout program if:

    1) The machine or equipment:
  • has no potential for stored or residual energy or re-accumulation of stored energy after shut down;
  • has a single energy source that can be readily identified and isolated;
  • is isolated from that energy source and locked out during servicing or maintenance.
    2) The isolation and locking out of that energy source will completely de-energize and deactivate the machine or equipment.
    3) A single lockout device will achieve a locked-out condition.
    4) The lockout device is under the exclusive control of the authorized employee performing the servicing or maintenance.
    5) The servicing or maintenance does not create hazards for other employees.
    6) The employer, in utilizing this exception, has had no accidents involving the unexpected activation or re-energizing of the machine or equipment during servicing or maintenance.
    One last note: If I had my druthers, the name of the standard would be lockout/tagout/tryout.