How Lockout/Tagout works under OSHA
Lockout/Tagout (LOTO) is OSHA's name for controlling hazardous energy while a machine is being serviced or maintained. For general industry, the standard is 29 CFR 1910.147 — The Control of Hazardous Energy. It requires the employer to develop a documented, machine-specific energy-control procedure (1910.147(c)(4)) so that a machine can't unexpectedly start up or release stored energy and injure the person working on it. The generator above produces exactly that per-machine procedure.
A complete LOTO compliance program is more than one procedure. It also needs a written energy-control policy, trained authorized and affected employees, proper lockout devices, and an annual periodic inspection of each procedure (29 CFR 1910.147(c)(6)) performed by an authorized employee other than the one using the procedure.
Construction is different — 1910.147 does not apply
A critical and commonly-missed point: 1910.147 expressly excludes construction (1910.147(a)(1)(ii)). On a construction site there is no single blanket LOTO standard. Instead, energy control is cited per source:
- Electrical: 29 CFR 1926.417 (Subpart K — lockout/tagging of circuits); power transmission/distribution adds 1926 Subpart V.
- Concrete & masonry equipment: 29 CFR 1926.702(j) (Subpart Q).
- All other energy: the employer's safety program and training duties (29 CFR 1926.20(b) / 1926.21(b)(2)) plus the General Duty Clause, Section 5(a)(1).
1910.147 EXCLUDES construction (1910.147(a)(1)(ii)). Do NOT brand a construction LOTO tool as '1910.147 compliant' without that caveat. The construction branch of the generator cites the correct 1926 standard for each energy type — never label a construction procedure “1910.147 compliant.”
The six hazardous-energy types
Every LOTO procedure starts by identifying which forms of energy are present. These are the six the generator covers, with how each is verified and its construction-correct citation.
| Energy type | How to verify zero energy | Construction citation (1926) |
|---|---|---|
| Electrical | Use a calibrated voltage tester on all phases. Attempt normal start-up to confirm de-energization. | 29 CFR 1926.417 (Subpart K — Electrical: lockout/tagging of circuits); power transmission/distribution work also 29 CFR 1926 Subpart V (1926.961). |
| Hydraulic | Read pressure gauges — must show 0 PSI. Attempt to cycle hydraulic controls to confirm no movement. | 29 CFR 1926.20(b) / 1926.21(b)(2) (employer safety program & training) + General Duty Clause, Section 5(a)(1) — no construction-specific hydraulic LOTO standard; 1910.147 does not apply to construction. |
| Pneumatic | Check all pressure gauges read 0 PSI. Attempt to actuate pneumatic controls. | 29 CFR 1926.20(b) / 1926.21(b)(2) (employer safety program & training) + General Duty Clause, Section 5(a)(1) — no construction-specific pneumatic LOTO standard; 1910.147 does not apply to construction. |
| Thermal | Use calibrated infrared thermometer. Temperature must be below the safe threshold for the specific material/surface. | 29 CFR 1926.20(b) / 1926.21(b)(2) (employer safety program & training) + General Duty Clause, Section 5(a)(1); electric-heater isolation also 29 CFR 1926.417 — 1910.147 does not apply to construction. |
| Chemical (Stored Energy) | Atmospheric monitoring with calibrated gas detector. Verify no flow at drainage points. | 29 CFR 1926.20(b) / 1926.21(b)(2) + General Duty Clause, Section 5(a)(1); covered processes also 29 CFR 1926.64 (PSM) — 1910.147 does not apply to construction. |
| Mechanical / Gravity (Stored Energy) | Physically attempt to move blocked components. Visual inspection of blocking/cribbing stability. | 29 CFR 1926.702(j) (Subpart Q — Concrete & Masonry: equipment lockout for bulk handling/mixing) where applicable; otherwise 29 CFR 1926.20(b) / 1926.21(b)(2) + General Duty Clause, Section 5(a)(1) — 1910.147 does not apply to construction. |
Worked examples
1 · Conveyor in a warehouse (general industry). A jam clearance on a motor-driven conveyor exposes electrical and mechanical/gravity energy. The procedure: notify operators → stop with the normal control → open and lock the disconnect → block the incline section so it can't roll back → test for zero voltage and attempt a restart → do the work → reverse the sequence to re-energize. Governing standard: 29 CFR 1910.147 — The Control of Hazardous Energy, with the annual 29 CFR 1910.147(c)(6) inspection on file.
2 · Concrete batch-plant mixer (construction). Servicing a bulk cement-handling mixer exposes electrical and mechanical/gravity energy on a construction site, so 1910.147 does not apply. Electrical isolation is cited to 29 CFR 1926.417; the mixer/bulk-handling lockout is 29 CFR 1926.702(j); the rest falls under the employer's program duties (1926.20/1926.21) and the General Duty Clause. The generator's construction branch stamps each of those automatically.
What to do next
- Print the procedure and keep it at the machine. 1910.147(c)(4) wants it documented and available to authorized employees.
- Train your people. Authorized employees must be trained on the energy type, magnitude, and isolation methods; affected employees on the purpose and use of the procedure (1910.147(c)(7)).
- Run the annual inspection. Schedule the 29 CFR 1910.147(c)(6) periodic inspection and document it — this is one of the most-cited LOTO gaps.
- Add the program-level pieces: group lockout, shift change, and contractor coordination (1910.147(d)–(f)). The procedure is the per-machine layer; the program wraps around it.
Frequently asked questions
What OSHA standard covers Lockout/Tagout?
For general industry, 29 CFR 1910.147, The Control of Hazardous Energy (Lockout/Tagout), requires employers to establish procedures for isolating energy sources before servicing or maintenance. 1910.147 expressly EXCLUDES construction (1910.147(a)(1)(ii)). Construction work is instead governed by 29 CFR 1926.417 (electrical, Subpart K), 1926.702(j) (Subpart Q), 1926 Subpart V + General Duty Clause: electrical energy control is 29 CFR 1926.417, concrete/masonry equipment is 1926.702(j), power transmission/distribution is Subpart V, and other energy sources fall under the employer's safety program (1926.20/1926.21) and the General Duty Clause. Do not represent a construction LOTO procedure as "1910.147 compliant."
When is LOTO required?
In general industry, 29 CFR 1910.147 applies to the servicing and maintenance of machines and equipment where unexpected energization, start-up, or release of stored energy could injure employees (1910.147(a)(1)(i)). Servicing includes setting up, adjusting, lubricating, cleaning, unjamming and tool changes (1910.147(b)). During normal production operations it applies only when an employee removes or bypasses a guard, or places a body part in the point of operation or a danger zone (1910.147(a)(2)(ii)).
What is the difference between lockout and tagout?
Lockout uses a lock to hold an energy-isolating device in a safe or off position; tagout uses a prominent warning tag (29 CFR 1910.147(b)). If the device can be locked out, the program must use lockout unless the employer demonstrates that its tagout system gives full employee protection, with additional measures such as removing a circuit element or blocking a switch (1910.147(c)(2)(ii) and (c)(3)). Where the device cannot be locked, tagout is used (1910.147(c)(2)(i)).
Who is an 'authorized employee' under LOTO?
Under 29 CFR 1910.147(b), an authorized employee is someone who locks out or tags out machines or equipment to perform servicing or maintenance. They must be trained in the recognition of applicable hazardous energy sources, the type and magnitude of energy, and the methods and means of isolation and control (1910.147(c)(7)(i)(A)).
How often must LOTO procedures be reviewed?
OSHA requires a periodic inspection of each energy control procedure at least annually (29 CFR 1910.147(c)(6)), performed by an authorized employee other than the ones using the procedure. Where lockout is used, it includes a review with each authorized employee; where tagout is used, with each authorized and affected employee (1910.147(c)(6)(i)(C) and (D)). The employer certifies each inspection (1910.147(c)(6)(ii)).
What does this generator produce?
A machine-specific energy control procedure, the document 1910.147(c)(4) requires for each piece of equipment. The rest of an energy control program is your written policy, authorized and affected employee training and records, the annual periodic inspection, and procedures for group lockout, shift change, and contractor coordination. Have a qualified person review the procedure against the actual equipment before use.
Sources & verification
- 29 CFR 1910.147 — The Control of Hazardous Energy (general industry)
- 29 CFR 1926.417 — Lockout and tagging of circuits (construction)
- 29 CFR 1926.702 — Requirements for equipment and tools (concrete & masonry)
Citations verified 2026-10-05 against the primary CFR text. This generator produces a template energy-control procedure — it is an aid, not legal advice, and not a certification that any specific machine or program is compliant. Have a qualified person review every procedure against the actual equipment. State-Plan states may impose additional requirements.
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