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When to Lockout a Machine


The Balance Between Compliance and Safety

Lockout-Tagout is an essential component to a workplace safety program. When utilized properly, it protects works from the potential re-energization of equipment during maintenance. However, there are times when Lockout-Tagout may be safely avoided. Understanding when it’s acceptable and when it’s not is key to creating an effective program.

When Lockout-Tagout May Not be Necessary

Cord and Plug Systems

  • Equipment that consists of only a cord and plug, where electrical energy is the only source of hazard, is exempt from having a Lockout-Tagout procedure. OSHA 1910.147(c)(4)(i) lists the 8 criteria for exemption.

Hot Tap Work

  • Hot tap work done on pipelines may be exempt from Lockout-Tagout provided the employer can prove that:
    • Continuity of the system or pipeline flow is essential to plant operation;
    • Shutdown of the system is shown to be impractical, and;
    • Alternate safety measures are taken to provide protection for the workers.

Minor Tool Change

  • If the tool change or machine adjustment is routine in activity, a repetitive task, and integral to operation it may be done without utilizing a lockout-tagout procedure; it must not expose the employee to hazardous energies.


lockout-tagout-surveying-equipment-with-ipadWhen Lockout-Tagout is Necessary

Servicing Activity

  • Lockout-Tagout is required every time a machine is taken out of service for maintenance. This includes, but is not limited to the following tasks: repairs, adjustments, inspections, cleaning, unjamming, and other maintenance activities.

Worker is Exposed to Hazardous Energy

  • Any time an employee’s task will put them at risk to the release of uncontrolled energy, Lockout-Tagout must be utilized. This includes the following scenarios:
    • Removing a guard from the system.
    • Bypassing an interlock or other safety devices.
    • Placing any part of their body in harm’s way.


Alternate Procedures

In the event that OSHA deems Lockout-Tagout to be necessary, but lockout is still impractical, it may be possible to create an alternate means of compliance. Creating a task-specific standard operating procedure can give employees an equal level of protection while keeping part of the system live. A proper alternate procedure should include the following components:

  • Exact scope of work and tasks to be done.
  • Step-by-step instructions for partial shutdown.
  • Removal and lockout of certain energy sources.
  • List of potential hazards that may still exist.
  • Methods of accomplishing the task with minimal risk to the employee.
  • Alternate means of protecting the employee from harm (such as PPE and other tools).

Determining when to lockout equipment can be a challenge for employees. By having written procedure both for Lockout-Tagout and standard operations, employees can more easily determine how and when to lockout equipment.

For assistance writing these procedures, contact ESC Services. In addition to Lockout-Tagout, ESC is capable of designing standard operation procedures that can be utilized for work not covered by the 1910.147 regulation.


About the Author:

Ashley Kehus is a mechanical engineer at ESC Services, Inc.  She has helped manage dozens of Lockout-Tagout implementation projects for many large companies around the world.  Ashley’s specialty is with large, complex systems that are interconnected with other critical systems.  To contact Ashley to learn more about this articles topic, simply submit a request through the contact us page.


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