Lockout/tagout is the procedure that keeps a machine from starting while someone is working inside it, and the OSHA standard behind it is more specific than most people expect. It prescribes the sequence for isolating equipment and the sequence for releasing it, who may apply and remove a lock, what has to be written down, and an inspection of the procedure itself at least once a year. This article sets out what the rule requires, what it leaves to the employer, and what a lockout checklist and a periodic inspection should cover.
A note on scope: this summarizes the federal OSHA standard for general industry, 29 CFR 1910.147, the control of hazardous energy. It covers servicing and maintenance of machines and equipment where unexpected energization, start-up or the release of stored energy could injure employees. It does not cover construction or agriculture, maritime employment, electric utility installations for generation, transmission and distribution, electrical hazards covered by subpart S, or oil and gas well drilling and servicing. Normal production operations are covered only when an employee removes or bypasses a guard or places part of the body into the point of operation or a danger zone, and minor tool changes and adjustments that are routine, repetitive and integral to production are excluded when alternative measures give effective protection. Cord-and-plug equipment is also outside the standard when unplugging controls the hazard and the plug stays under the exclusive control of the person doing the work. States with their own OSHA-approved plans can set different rules, and nothing here is legal advice.
The standard is built around an energy control program with three parts: energy control procedures, employee training and periodic inspections (29 CFR 1910.147(c)(1)). Each part has its own requirements.
Lockout comes first. Where an energy isolating device can be locked out, the program uses lockout, unless the employer can demonstrate that a tagout system provides full employee protection, with additional measures such as removing a valve handle, blocking a controlling switch or opening an extra disconnect (1910.147(c)(2) and (c)(3)). Where a device cannot be locked, tagout is used. Since January 2, 1990, new equipment, and equipment that is replaced, majorly repaired, renovated or modified, must have isolating devices designed to accept a lock.
Procedures are developed, documented and used for each machine or piece of equipment (1910.147(c)(4)). They state the intended use of the procedure, the specific 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, and how to test that the isolation worked. The only exception to documenting a procedure applies when all eight conditions listed in the standard are met, among them a single, readily identified energy source, no stored or residual energy, a single lockout device under the exclusive control of the authorized employee, and no accidents from unexpected energization.
Devices are provided by the employer and singularly identified (1910.147(c)(5)). Locks and tags are durable, standardized within the facility by color, shape or size, substantial enough that a lock cannot be removed without bolt cutters or unusual techniques, and marked with the identity of the employee who applied them. Tags warn against energizing with a legend such as Do Not Start, Do Not Open or Do Not Operate, and their attachment is self-locking, non-reusable and able to withstand at least 50 pounds.
Training covers three groups (1910.147(c)(7)). Authorized employees, who apply the locks, are trained to recognize hazardous energy sources, the type and magnitude of the energy, and the methods of isolating it. Affected employees, who operate or work around the equipment, are instructed in the purpose and use of the procedure. All other employees in the area are instructed about the procedure and the prohibition on restarting locked or tagged equipment. Retraining is required when jobs, machines, processes or procedures change, and whenever a periodic inspection reveals deviations. The employer certifies the training with each employee's name and dates.
Periodic inspection at least annually (1910.147(c)(6)). The employer inspects each energy control procedure at least once a year to ensure that the procedure and the standard are being followed. The inspection is performed by an authorized employee other than the ones using the procedure being inspected, it is conducted to correct any deviations or inadequacies, and it includes a review of responsibilities with each authorized employee, and with each affected employee too where tagout is used. The employer certifies the inspection, identifying the machine or equipment, the date, the employees included and the person who performed it.
The sequence is fixed. Only the authorized employees doing the work apply lockout or tagout (1910.147(c)(8)), affected employees are notified before devices are applied and after they are removed (1910.147(c)(9)), and application follows six steps in order (1910.147(d)): prepare for shutdown knowing the type and magnitude of the energy and how to control it; shut the equipment down by its established procedure; locate and operate every energy isolating device; affix the locks or tags to each one; relieve, disconnect, restrain or otherwise render safe all stored or residual energy; and verify that isolation and de-energization have been accomplished before starting work.
Release has its own steps (1910.147(e)). Before devices are removed and energy restored, the work area is inspected to ensure nonessential items are gone and the equipment is operationally intact, all employees are safely positioned or removed, affected employees are notified, and each device is removed by the employee who applied it. When that employee is not available, the device may be removed under the employer's direction only through a specific documented procedure: verify the employee is not at the facility, make all reasonable efforts to contact them, and ensure they know before they resume work there.
Four special situations are addressed in 1910.147(f): temporarily re-energizing to test or position equipment, which follows clear, remove employees, release, energize, then re-isolate; outside contractors, who exchange procedures with the on-site employer; group lockout, where an authorized employee holds primary responsibility and each worker places a personal lock on the group device or lockbox; and shift changes, which need a procedure for the orderly transfer of protection between off-going and oncoming employees.
The format of the procedure, the certifications and the training record. The standard says what each must contain, not what it looks like. A machine-specific procedure can be a page in a binder, a laminated card on the machine or a form on a phone, as long as it holds the four elements in paragraph (c)(4)(ii), and the inspection and training certifications can be paper or electronic as long as they identify what the standard asks for.
"At least annually" is a floor. A procedure used daily by a dozen authorized employees may warrant more frequent inspection than one used twice a year. The standard sets the minimum and leaves the schedule to the employer.
The documentation exception is narrow. It is tempting to treat simple machines as exempt from written procedures, but all eight conditions have to hold, including that a single lock achieves isolation and that there have been no accidents from unexpected energization. Equipment with a pneumatic line as well as a power feed, a capacitor that holds a charge, or a raised part that can fall does not qualify.
How to know who holds which lock. The standard requires devices to identify the employee and, in group lockout, requires the lead to be able to ascertain each member's exposure status. It does not say how. On paper that is a sign-in sheet at the lockbox; the practical question is whether it is current at the shift change.
Because paragraphs (d) and (e) prescribe the sequence, a lockout checklist writes itself around them. Our lockout/tagout checklist, free as a PDF, Excel or Word file, follows the same order and is meant to be used alongside the machine's written procedure, not instead of it.
Before shutdown:
Shutdown and isolation:
Verification:
Release:
The standard treats deviations as something to find and fix, not only to record. Where a periodic inspection finds a procedure out of step with the machine or with how people actually work, the inspection is conducted to correct the deviations, and retraining is required whenever an inspection reveals, or the employer has reason to believe, that employees' knowledge or use of the procedures has fallen short (1910.147(c)(6)(i)(B) and (c)(7)(iii)(B)). The common deviations are familiar: a disconnect that is no longer where the procedure says, a new air line on a machine whose procedure lists only electrical energy, a lock applied by someone other than the person doing the work, or a release done without telling the operators.
Two kinds of finding deserve their own handling. A lock found on equipment with its owner gone home is a paragraph (e)(3) situation, and the only correct path is the documented removal procedure. A piece of hardware that no longer meets paragraph (c)(5), a tag whose print has faded or a lock that opens without its key, comes out of the pool rather than back into it.
Lockout programs fail in the same places paper inspections fail: the procedure is in a binder in an office, the periodic inspection is a signature once a year, and nobody can say at 3 a.m. whose locks are on the press.
For how lockout fits with permits for hot work, confined spaces and other controlled work, see designing digital permit-to-work and lockout/tagout.
If you run lockout across a plant or several sites, see how Vardian handles safety procedures and corrective action: machine-specific procedures on the phone, steps and locks recorded as they happen, and deviations that become work orders.
Bring a round, an inspection or a maintenance process to a demo, and we'll show how it runs in Vardian.
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