Lockout/Tagout on Construction Sites: When 1910.147 Applies and Who Counts as Authorized

When lockout/tagout is required

The OSHA standard for the control of hazardous energy, 29 CFR 1910.147, applies to the servicing and maintenance of machines and equipment where the unexpected energization, start-up, or release of stored energy could injure a worker. That covers electrical energy, but also hydraulic, pneumatic, mechanical, thermal, chemical, and gravitational energy — anything that can move, start, or release and hurt the person working on it.

A note on which rule applies on a construction site: 1910.147 is written as a general industry standard, but its energy-control method is the recognized approach and is routinely applied to servicing and maintenance of machines and equipment on construction projects. Construction electrical work also falls under 29 CFR 1926 Subpart K, including 1926.417 on lockout and tagging of circuits. The practical takeaway for a foreman is not the citation number — it is that whenever a worker services or maintains equipment that could unexpectedly energize or release stored energy, a documented energy-control procedure is required.

The exceptions worth knowing

• →Minor servicing during normal production operations — tasks that are routine, repetitive, and integral to production may fall outside full LOTO if they are performed using alternative measures that provide effective protection (for example, a properly guarded, interlocked setup). This exception is narrow and frequently misapplied.
• →Cord-and-plug connected equipment — if the only energy source is a cord and plug, and the plug is under the exclusive control of the person doing the work (in their hand, in their pocket, in sight), unplugging it can substitute for lockout.
• →Work on energized systems where de-energizing is infeasible — this does not exempt you; it triggers different, stricter requirements (for electrical work, the energized-work rules), not a free pass.

Authorized vs. affected employees — the distinction that trips crews up

This is the question the search data shows people getting wrong constantly, and it matters because the training requirements and the legal responsibility differ by role. There are three roles under 1910.147:

• →Authorized employee — the person who actually locks out and tags out the equipment to perform the servicing or maintenance. They apply the energy-control procedure. They receive the most extensive training and are the only ones permitted to apply and remove their own locks.
• →Affected employee — a worker whose job requires them to operate or use the equipment being serviced, or who works in the area where servicing is being performed. They do not apply locks; they must know when LOTO is in effect and understand not to start or use locked-out equipment.
• →Other (all other) employees — anyone else who may be in an area where energy-control procedures are used. They receive awareness-level instruction, primarily about the prohibition against restarting or bypassing a locked-out machine.

The single most important rule of the authorized role: only the authorized employee who applied a lock may remove it, and each authorized employee applies their own lock. You never remove another worker’s lock because a shift ended or the person went home. There is a specific, rare exception procedure for removing an absent employee’s lock — it requires verifying the person is not on site, making reasonable efforts to notify them, and following the employer’s documented procedure — but it is the exception, not a shortcut a foreman uses to keep the job moving.

The energy-control sequence: shutting down safely

The heart of any LOTO program is the energy-control procedure — the ordered sequence for taking a machine to a genuine zero-energy state and bringing it back. It runs like this:

1. Prepare for shutdown — the authorized employee identifies every energy source on the equipment and the specific means to control each one.
2. Notify affected employees — everyone who operates or works around the equipment is told the machine is going down for servicing and why.
3. Shut down the equipment — using the normal stopping procedure, bring the machine to an orderly, complete stop.
4. Isolate the energy sources — operate the disconnects, valves, and switches that separate the equipment from every energy source identified in step one.
5. Apply lockout/tagout devices — each authorized employee places their own lock (and tag) on each isolation point so it cannot be re-energized.
6. Release or restrain stored energy — bleed hydraulic and pneumatic pressure, discharge capacitors, block suspended parts, relieve springs and gravity; anything that can still move or release must be made safe.

Then the step people skip under time pressure and get killed for: verify isolation. Before touching the work, the authorized employee confirms the machine is truly de-energized — try the start button (then return it to off), test for voltage, check gauges. Zero-energy verification is not optional and it is not a formality. Bringing the equipment back reverses the sequence: clear tools and people, confirm controls are neutral, remove the locks (each person removes their own), and notify affected employees before restarting.

Equipment-specific procedures: why one generic LOTO sheet isn’t enough

A common citation is having a single, generic lockout procedure taped to a wall and nothing else. The standard requires documented, equipment-specific energy-control procedures for machines with more than one energy source or a non-obvious shutdown sequence. The procedure has to spell out, for that specific machine, the scope, the steps to shut it down and isolate it, the means to control each energy source, and how to verify zero energy.

There is a limited exception where a single generic procedure can suffice — essentially a machine with a single, readily identifiable energy source that is easy to isolate, with no stored energy and no potential for re-accumulation, among other conditions. Most real equipment on a jobsite does not meet all of those conditions. If a machine has hydraulics and electrical, or capacitors that hold a charge, or a source that can re-pressurize, it needs its own written procedure. Do not let a wall poster stand in for the specific sheet the machine requires.

Group lockout: many hands, many locks

When more than one authorized employee services the same equipment, the standard requires group lockout that gives each worker the same protection they would have with their own personal lock. The mechanism is usually a group lockout device or box: the energy-isolation points are locked, the keys go into a group box, and every authorized employee places their personal lock on that box. No one’s protection is removed until they personally remove their own lock.

The principle that must never be violated: every worker exposed to the hazard controls their own lock and no one else can release their protection. A single supervisor lock covering a whole crew is not group lockout — it is a way for someone to get hurt when the supervisor pulls the lock and a worker is still inside the machine.

The annual inspection everyone forgets

1910.147 requires a periodic inspection of the energy-control procedure at least annually. This is not the daily use of LOTO — it is a separate review to make sure the written procedures are still accurate and that authorized employees are following them correctly. An authorized employee who is not involved in the specific procedure being inspected must perform the review, and it has to include a check that the procedure’s steps are being applied and that employees understand their responsibilities. The inspection is documented, identifying the machine, the date, the employees involved, and the person who performed it.

This is exactly the kind of requirement that vanishes on a busy site — until an inspector asks for the last periodic inspection record and there isn’t one. Like the daily briefing, the periodic inspection is a record you either have or you don’t, and “we do it, we just don’t write it down” gets you no credit. Building the habit of documenting energy-control training and procedure reviews is the same discipline that makes the whole safety program defensible.