When Lockout Isn’t Feasible: Understanding Alternate Methods of Energy Control
What the recent 2024 OSHA interpretation says
On October 21, 2024, OSHA issued a letter of interpretation titled “Lockout/Tagout (LOTO) Feasibility and ‘Alternative Methods’”.In that letter, OSHA addressed a question concerning when power must remain required for set-ups or change-over tasks (e.g., inching/jogging operations) and whether a true “alternative method” to energy isolation was allowed. OSHA’s key points:
Section 1910.147(f)(1) allows temporary removal of lockout or tagout devices and re-energization only when necessary to perform particular tasks that require energization (e.g., test or reposition equipment).
If power must remain for a portion of the servicing or maintenance (e.g., change-over operations where jog/inch is essential), the employer must still isolate and lockout at all other times and must provide effective protective measures during the energized phases.
OSHA explicitly stated that it does not recognize the definitions of “Alternative Methods” and “Feasibility” as found in consensus standards such as ANSI Z244.1‑2016 or ANSI B11.0‑2020 as automatically satisfying the regulation.
Employers must show that employee protection is maintained during any energized phase, and that the remainder of the servicing or maintenance still complies with § 1910.147.
What this means in practice
In short: full isolation (lockout/tagout) remains the default for servicing and maintenance under 1910.147. Alternate or reduced-isolation approaches may only be considered in very limited circumstances, and only when the employer can document that protection is equivalent or better. The mere fact that a machine needs to come back into production or is critical to operations does not change the fundamental requirement that whenever employees are exposed to unexpected energization or release of stored energy, energy must be controlled by isolation unless the narrow exceptions apply.
Note also: the alternate method cannot be justified merely because production is impacted—what matters is that employee protection is maintained and the machine is safely usable when needed.
Key Conditions for Acceptable Alternate Methods
Here are the conditions you must evaluate and document before relying on an alternate method rather than full LOTO:
Task scope – The work must either qualify under the minor-servicing exception (which is narrow) or involve a phase of energized testing/positioning under § 1910.147(f)(1). For everything else, full isolation is required.
Employee exposure – As always, the key question is: Will employees be exposed to hazardous energy (including unexpected startup or release of stored energy)? If yes, then energy control applies.
Alternate protections in place – If you propose an alternate approach (e.g., machine guarding, inch-safe service, two-hand inching, safety-rated interlocks, remote devices), you must show that the level of protection is equivalent or better than what you would achieve by isolating the energy source.
Procedure and training – You must incorporate the alternate method in a documented procedure, train the employees, and have monitoring/verification of control effectiveness.
Sequence and transition controls – If any re-energization is required for testing or positioning, the employer must follow the required sequence: clear tools/materials, remove employees from hazard zone, remove the lockout/tagout devices, energize while maintaining protections, then de-energize and re-isolate if further servicing remains.
Verification & audit – As part of your energy control program you must periodically inspect that the alternate method is implemented correctly and still valid for the task conditions.
In-Depth Example Scenarios of Acceptable Alternate Methods
Below are several realistic examples of alternate methods that may be acceptable under very specific conditions — along with what makes them acceptable, and what pitfalls must be avoided.
1. Inch-Safe Service on a Printing Press
Scenario: A web-fed printing press requires frequent clearing of paper jams and minor adjustments (e.g., roll alignment). The machine cannot be fully locked out because production must continue and stopping for full disassembly is impractical.
Alternate method implemented: Use of an engineered “inch” (or jog) control mode. The procedure ensures: the machine is in STOP/SAFE; a pre-start check ensures tools/materials clear; authorized employee activates “inch” control to move the machine component, then returns to STOP/SAFE before servicing starts; repeat as needed until servicing is finished.
Why this can be acceptable: OSHA has recognized this technique in the printing industry as an effective form of alternate protection for minor servicing tasks that are routine, repetitive and integral to production operations.
Critical implementation details:
The “inch” control must be under exclusive control of the servicing employee(s) and prevent unintended startup.
The hazard zone must be safeguarded by machine guarding or other engineering means when energized.
The task must remain “minor servicing” — i.e., routine, repetitive, integral to production, short-duration, and not a full disassembly or major repair. If not, then full LOTO applies.
Pitfall to avoid: Applying this method when the task is non-routine or when employees must reach into dangerous zones while the machine is energized without appropriate safeguards — that would violate the standard (per die-setting hydraulic press example).
2. Use of a Monitored Power / Safety PLC System for Minor Tool Change
Scenario: A packaging line conveyor needs frequent tool changes (knife blade changes) during production.
Alternate method implemented: The machine is equipped with safety-rated interlocks, two-hand enabling device, presence sensing system, safety PLC that monitors condition. During the tool change, the machine drive remains energized but the hazardous zone is blocked and motion controlled to inch only, and the toolbox/door interlock prevents unintended startup; control logic ensures the only motion possible is slow incremental inching for positioning, then return to inactive state before access is permitted.
Why this could be acceptable: If the manufacturer’s safety system is proven, validated, and provides protection that equals or exceeds what you’d get from full isolation (i.e., no employee exposure to uncontrolled energy while accessing hazard zone). As some articles note, alternative methods such as interlocks, enabling devices, remote controls are possible for tasks that are routine and integral.
Conditions for acceptance:
Documented risk assessment showing the hazard and how the control system addresses it.
Verification of safety performance (e.g., safe stop, redundant monitoring, test of E-stop function).
Procedure describes exactly how this “alternate method” works, when it applies, and when full lockout is required.
The task must still probably fall under “routine, repetitive, integral to production” if foregoing full isolation.
Pitfall to avoid: Assuming that because you have a safety PLC it replaces full LOTO in all circumstances. OSHA has been clear: For servicing or maintenance tasks outside the minor servicing exception or beyond repositioning/testing, full energy isolation is required.
3. Temporary Re-Energization for Testing or Positioning
Scenario: A machine undergoing maintenance must be jogged or positioned to verify alignment of assemblies, sensors, or make an adjustment that cannot be made while fully de-energized.
Alternate method implemented: The procedure uses full lockout; work is done while de-energized; then when testing/positioning is required the authorized employee clears the work area, removes the lockout devices under controlled condition, re-energizes the machine, with safeguarding (guards, presence sensors) in place; after the test/position step the machine is shut off, energy isolated again, and lockout reapplied before further servicing.
Why this is acceptable under 1910.147(f)(1): OSHA specifically allows temporary removal of lockout/tagout devices and re-energization when necessary to test or position machines or components — but only in that limited phase, and with required sequence steps.
Sequence to observe (per OSHA):
Clear machines of tools/materials – § 1910.147(e)(1)
Remove employees from hazardous areas – § 1910.147(e)(2)
Remove the lockout or tagout devices as specified – § 1910.147(e)(3)
Energize the machine and employ effective employee protection while testing or positioning – § 1910.147(f)(1)
Then turn off all systems, isolate the machine from energy source, and reapply lockout/tagout if additional servicing remains – § 1910.147(d)
Pitfall to avoid: Treating this temporary re-energization as a justification to keep the machine energized throughout servicing, or skipping the re-isolation step and proceeding with servicing without full isolation.
4. CNC Machine Zero-Energy Verification Mode
Scenario: A CNC mill requires calibration of axis sensors and jogging of the table to confirm positional accuracy.
Alternate Method Used:
The machine includes a “Zero-Energy Verification” or “Maintenance Mode” selectable only by key switch.
Control logic disables spindle rotation, tool changer motion, and coolant pumps.
Axis movement is limited to ≤10 mm/s (slow jog) under two-hand enabling control.
Light-curtain guarding and door interlocks remain active.
Why It’s Acceptable:
The key switch, safety circuit category, and speed limitation combine to ensure operators aren’t exposed to hazardous motion. OSHA considers this an acceptable alternate method because the hazard itself is removed or sufficiently reduced during the energized phase.
Documentation Needed:
Risk assessment verifying residual motion energy is below injury threshold; annual validation of the maintenance-mode function.
5. Electrical Troubleshooting with Insulated Test Leads and Barriers
Scenario: A maintenance electrician must verify voltage on a control circuit before restoring power.
Alternate Method Used:
Work is done under a qualified-person electrical safety procedure, following NFPA 70E Article 130.
Energized parts are exposed only as necessary for diagnostic measurement.
The worker uses CAT-rated insulated meters, arc-rated PPE, and maintains restricted approach boundaries using insulated barriers.
Why It’s Acceptable:
This isn’t a LOTO bypass; it’s energized electrical work permitted under a justified energized condition for testing. OSHA and NFPA 70E allow this if no feasible de-energized alternative exists and protective boundaries are established.
It counts as an “alternate method” only if fully documented and controlled.
Key Requirements:
Energized work permit.
Shock and arc-flash risk assessment.
Insulated tools, barriers, and PPE.
Guidelines for Choosing the Right Approach
When you’re developing, reviewing or auditing a hazardous energy control (LOTO) program and considering an alternate method, use the following decision-framework:
Define the task – What exactly is the employee going to do (clearing a jam, change‐over, test, adjustment, repair)? Will power need to be available (inch, jog, reposition)?
Does it qualify for the minor servicing exception? – Is the task routine, repetitive, integral to production, and could it be performed without exposure to uncontrolled energy under proper safeguards? If yes, an alternate method might be acceptable; if no, full isolation is required. (See OSHA’s guidance on printing press “minor servicing” and inch-safe service).
Is the task outside that exception but requiring energized work? – If so, then you may implement the temporary re‐energization step under § 1910.147(f)(1), but must still isolate before and after that energized phase.
Risk assessment – Conduct a documented risk assessment: identify hazards, evaluate exposure, existing safeguards, residual risk. Assess whether the proposed alternate method provides protection equal or better than full isolation. (Even though OSHA won’t adopt the ANSI definitions wholesale, they expect equivalent protection).
Procedure development – Write a machine‐specific procedure: describe when full LOTO applies, when the alternate method applies, the sequence of operations, responsibilities, required protection, verification steps, training requirements, audit/inspection.
Training and verification – Train affected employees clearly on both the full LOTO method and the circumstances under which the alternate method applies. Conduct periodic inspections to ensure correct implementation.
Use caution and documentation – Because alternate methods represent a departure from the default full isolation approach, documentation and employer justification are critical. In an inspection, OSHA will want to see that you’ve evaluated and the protection is effective.
Don’t rely on “critical to production” as justification alone – The need for production continuity or because equipment is critical does not by itself justify skipping full isolation. The legal requirement is about controlling exposure to hazardous energy; alternate methods must be justified on that basis.
Summary and Takeaway
In summary:
Full energy isolation (lockout/tagout) remains the gold standard under 29 CFR 1910.147 whenever servicing or maintenance exposes employees to hazardous energy.
Alternate methods are possible but only under very controlled, limited circumstances: either the minor servicing exception (routine, repetitive, integral) or the temporary re-energization for testing/positioning under § 1910.147(f)(1).
For any alternate method, you must show that the protection provided is equivalent or superior, document procedures, train employees, and verify the effectiveness of controls.
The fact that the machine needs to come back into operation or is “critical to production” cannot override the requirement to protect employees from hazardous energy. The focus must remain on exposure and its control—not simply production continuity.
Real-world examples (inch-safe service on printing presses, monitored safety systems on conveyors, temporary re-energization for testing) illustrate how alternate methods can be implemented—but only when all the conditions are met.
Auditors, EHS professionals and employers should be cautious before adopting alternate methods: ensure you have solid risk assessments, documented procedures, safeguards in place, and training and inspection programs.
