Step 1: is it normal production or servicing?
Normal production operations are not covered by 1910.147; they fall under the machine guarding rules in subpart O ((a)(2)(ii)). The standard applies to servicing and/or maintenance ((a)(2)(i)), which the definitions in (b) describe broadly: constructing, installing, setting up, adjusting, inspecting, modifying, maintaining and servicing, including lubrication, cleaning or unjamming, adjustments and tool changes, where the employee may be exposed to unexpected energization or start-up or the release of hazardous energy.
Step 2: servicing during normal production is covered if...
Servicing or maintenance that takes place during normal production operations is covered by the standard only if ((a)(2)(ii)):
| Trigger | Source |
|---|---|
| An employee is required to remove or bypass a guard or other safety device; or | (a)(2)(ii)(A) |
| An employee is required to place any part of their body into the point of operation (where work is actually performed on the material) or into an associated danger zone during a machine operating cycle. | (a)(2)(ii)(B) |
Step 3: the minor servicing exception
A note to (a)(2)(ii) then excludes some of that work. Minor tool changes and adjustments, and other minor servicing activities, which take place during normal production operations, are not covered by the standard if all of these are true:
- They are routine,
- they are repetitive,
- they are integral to the use of the equipment for production, and
- the work is performed using alternative measures which provide effective protection (see subpart O).
The fourth condition is easy to overlook. The exception does not mean "no protection"; it means protection by something other than lockout, chosen so that it actually protects the employee doing that task. If no such measure is in place, the exception does not apply.
A three-question test for each task
| Question | If yes | If no |
|---|---|---|
| 1. Is the task servicing or maintenance (setting up, adjusting, cleaning, unjamming, tool change, lubrication, repair)? | Go to 2 | Normal production: machine guarding rules, not 1910.147 |
| 2. Does it happen during normal production and require removing or bypassing a guard, or putting a body part in the point of operation or a danger zone? | Go to 3 | If it happens outside production (machine stopped for maintenance), 1910.147 applies: use energy control procedures (lockout, or tagout where the standard permits). If it happens during production with no guard removal or body exposure, it is not covered |
| 3. Is it minor, routine, repetitive and integral to production, and is there an alternative measure that gives effective protection? | Exception applies. Good practice (not required by the text): document the task and the alternative measure | 1910.147 applies: use energy control procedures |
Writing this decision down for each recurring task, with the alternative measure named, is what turns "we don't lock out for that" from an opinion into a defensible part of your program.
Another exclusion: cord and plug equipment
The standard does not apply to work on cord and plug connected electric equipment where exposure is controlled by unplugging it and the plug is under the exclusive control of the employee doing the servicing or maintenance ((a)(2)(iii)(A)). Both parts matter: a plug left lying by a bench grinder while someone else can reach it does not meet the second one. Hot tap operations on pressurized pipelines have their own narrow exclusion in (a)(2)(iii)(B).
Common examples, sorted
- Clearing a jam inside the guard of a packaging machine by reaching into the danger zone: covered ((a)(2)(ii)(B)) unless it is minor, routine, repetitive, integral and done with an effective alternative measure. Jams that are irregular or unpredictable may not meet the "routine" condition.
- Changing a press brake punch and die: if done during normal production, a tool change with hands in the point of operation, so covered unless the exception's conditions (minor, routine, repetitive, integral, effective alternative measure) are met. Done with the machine stopped for setup, it is covered outright. See the press brake procedure example.
- Belt tracking a running conveyor from outside the guards: if no guard is removed and no body part enters a danger zone, it is not covered; if the guard comes off, it is. See the conveyor procedure example.
- Replacing a bearing or a motor: maintenance outside normal production, so covered.
These are general illustrations; the answer for a real task depends on how it is actually done on your machine.
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Questions
What is the minor servicing exception in OSHA lockout/tagout?
A note to 29 CFR 1910.147(a)(2)(ii) says minor tool changes and adjustments, and other minor servicing activities during normal production, are not covered by the lockout/tagout standard if they are routine, repetitive and integral to the use of the equipment for production, provided the work is performed using alternative measures which provide effective protection.
Does clearing a jam require lockout?
Unjamming is listed as servicing in the definitions in 1910.147(b). If it happens during normal production and requires removing or bypassing a guard or putting a body part into the point of operation or a danger zone, it is covered unless all conditions of the minor servicing exception are met, including an alternative measure that provides effective protection.
Do I need to lock out a machine that plugs into the wall?
Not under 1910.147 if the hazard is controlled by unplugging it and the plug is under the exclusive control of the employee doing the work ((a)(2)(iii)(A)).
Is an e-stop or interlocked guard an alternative measure?
The standard does not list approved measures; it requires alternative measures that provide effective protection, with reference to the machine guarding rules in subpart O. Whether a specific interlock or control gives effective protection for a specific task depends on its design and reliability, so evaluate and document it task by task.
Related: Lockout vs tagout · Authorized vs affected employee · Lockout/tagout program template
General information based on the text of 29 CFR 1910.147 on OSHA.gov; not legal advice. Check whether an OSHA-approved state plan applies to your workplace.