The 6 (and More) Steps of Lockout/Tagout (LOTO)

Introduction

Lockout/Tagout (LOTO) procedures are critical safety protocols designed to prevent the unexpected release of hazardous energy during the service and maintenance of machinery and equipment. A seemingly minor oversight during maintenance can lead to severe injuries or even fatalities, including crushed limbs, electrocution, burns, or exposure to hazardous chemicals.

LOTO procedures are not optional; they are mandated by regulatory bodies like OSHA (Occupational Safety and Health Administration) in the United States and equivalent organizations worldwide.

This blog post isn't just about listing the steps; it's about understanding the why behind each step. We’ll walk through the 6-step LOTO process outlined by OSHA, providing clear explanations and real-world examples to solidify your comprehension. A thorough understanding of LOTO is the first line of defense against workplace accidents. This blog post is part of our Fundamentals and Understanding series on lockout tagout. 

Why is LOTO So Important?

Before diving into the steps, let's reiterate the why. LOTO procedures address the following hazards:

• Unexpected Energization: A machine could be accidentally started while someone is working on it.
• Stored Energy Release: Even after a machine is "off," energy can remain stored (e.g., in capacitors, springs, hydraulic or pneumatic systems).
• Residual Energy: Heat, pressurized fluids, or gravity acting on suspended components.

LOTO ensures that all energy sources are isolated and rendered inoperative before maintenance begins. It also provides a clear visual warning (the tag) that the equipment should not be operated.

The Foundation: Understanding Energy Sources

Before performing LOTO, you must identify all potential energy sources associated with the equipment. This goes beyond just the electrical supply. Consider:

• Electrical: Direct power lines, generators, and batteries.
• Mechanical: Moving parts like flywheels, gears, and belts.
• Hydraulic: Pressurized fluids.
• Pneumatic: Compressed air or gases.
• Chemical: Hazardous substances.
• Thermal: Extreme heat or cold.
• Gravity: Suspended components.
• Stored Energy: Springs.

The 6 Steps of LOTO (OSHA 29 CFR 1910.147)

Step 1: Preparation for Shutdown (Planning)

This is the crucial planning phase. It's not just about grabbing a lock and tag. You need to understand the equipment inside and out.

• Identify the Equipment: Be specific. What machine, system, or process are you working on? What is its unique identification number or tag?
• Understand the Hazards: What types of energy are present (refer back to the energy sources list)? What are the specific hazards associated with this piece of equipment?
• Locate Isolation Points: Where are the switches, valves, breakers, or other devices that can disconnect the energy sources? Consult equipment manuals, schematics, and operating procedures.
• Notify Affected Employees: Inform all employees who might be affected by the shutdown, not just those directly involved in the maintenance. This includes operators, supervisors, and anyone in the vicinity.
• Gather Necessary Equipment: Collect the appropriate locks, tags, hasps, and any other specialized devices needed for this specific equipment. Ensure you have enough for all energy isolation points.
• Review LOTO procedure: Review the written LOTO program.

(Infographic Suggestion 2: "Preparation Checklist" - A checklist with icons for each sub-step: Identifying Equipment (a machine icon), Understanding Hazards (a warning triangle), Locating Isolation Points (a map pin), Notifying Employees (a megaphone), Gathering Equipment (a lock and tag).)

Example: Imagine you're servicing a large industrial mixer. The preparation phase would involve identifying the mixer's model number, understanding that it has electrical and mechanical (rotating blades) energy sources, locating the main power disconnect and any auxiliary power sources, notifying the mixing room operators and supervisors, and gathering the correct size and type of lock and tag for the electrical disconnect.

Step 2: Shutdown the Equipment

This step involves stopping the equipment using the normal stopping procedures. Don't just yank the power cord!

• • Follow the Manufacturer's Instructions: Use the established shutdown sequence outlined in the equipment's operating manual. This often involves a specific order of steps to safely bring the machine to a complete stop.
  • Activate Emergency Stops (If Necessary): Only use emergency stops if there's an immediate safety concern. Otherwise, follow the normal shutdown procedure.
  • Verify Complete Stop: Ensure that all moving parts have come to a complete rest, and any indicators show that the machine is in the "off" position.

Example: For the industrial mixer, this might involve pressing the "Stop" button on the control panel, waiting for the mixer blades to come to a complete stop, and confirming that the power indicator light is off.

Step 3: Isolation of Equipment

This is where you physically disconnect all energy sources identified in Step 1.

• Operate Isolation Devices: Turn switches to the "off" position, close valves, open breakers, and physically disconnect any other energy sources.
• Multiple Energy Sources: Remember, many machines have multiple energy sources. Don't forget about pneumatic lines, hydraulic lines, or even gravity-related hazards.
• Block or Restrain Moving Parts: If there's a risk of parts moving due to gravity or stored energy (like a spring), use blocks, wedges, or other restraints to prevent movement.

Example: For the mixer, this would involve switching the main electrical disconnect to the "off" position. If there were a pneumatic system for raising and lowering the mixer head, you would also need to shut off the air supply valve and bleed off any residual pressure.

Step 4: Application of Lockout/Tagout Devices

This is the heart of LOTO: physically securing the energy isolation devices in the "off" position.

• • Attach Locks: Each authorized employee performing service or maintenance should attach their own personal lock to each energy isolation device. The lock should be uniquely identifiable to that employee (e.g., with their name or employee number).
  • Attach Tags: Each lock should have a tag attached. The tag should clearly state:
    • "DO NOT OPERATE" (or similar warning)
    • The name of the person who applied the lock and tag.
    • The date and time the lock and tag were applied.
    • The reason for the LOTO (e.g., "Maintenance - Electrical Repair").
  • Use Hasps (When Necessary): If multiple employees are working on the same equipment, use a hasp. A hasp allows multiple locks to be attached to a single energy isolation point, ensuring that the energy cannot be restored until all employees have removed their locks.
  • Standardized Devices: Use standardized LOTO devices that are durable, clearly identifiable, and not easily bypassed.

Example: For the mixer, each electrician working on the electrical system would attach their own lock and tag to the main electrical disconnect. If a mechanic were also working on the mixer's drive mechanism, they would attach their lock and tag to a separate isolation point (or use a hasp on the main disconnect if appropriate).

Step 5: Control of Stored Energy

• • Release or Block Stored Energy: This might involve:
    • Bleeding off pressure in hydraulic or pneumatic lines.
    • Discharging capacitors.
    • Blocking or supporting raised components to prevent them from falling.
    • Allowing hot components to cool down.
  • Verify Zero Energy State: Attempt to operate the equipment's normal start controls (buttons, switches, etc.). The machine should not start. This is a critical test to confirm that the energy isolation is effective.
  • Check for Residual Hazards: Look for any other potential hazards, such as hot surfaces, sharp edges, or hazardous materials.

    This crucial step verifies that all energy has been successfully isolated and that no residual or stored energy remains.

  Example: For the mixer, after locking and tagging the electrical disconnect, you would attempt to start the mixer using the normal start button. The mixer should not start. You would also check any pressure gauges on pneumatic lines (if present) to ensure they read zero.

Step 6: Verification of Isolation

• • Periodic Checks: Regularly re-check the energy isolation devices and tags to ensure they remain in place and that no one has tampered with them.
  • Communication: Maintain clear communication between all authorized employees working on the equipment.
  • Re-Verification After Interruptions: If the work is interrupted for any reason (e.g., a shift change or a break), re-verify the isolation before resuming work.

    This step involves ongoing monitoring to ensure that the equipment remains in a safe, de-energized state throughout the service or maintenance work.

Restoring Equipment to Service

After the maintenance or service work is complete, there's a specific procedure to follow before restoring the equipment to operation:

1. 1. Inspect the Work Area: Ensure that all tools, spare parts, and other materials have been removed from the equipment.
   2. Ensure Employees are Clear: Verify that all employees are safely positioned away from the equipment.
   3. Remove LOTO Devices: Each authorized employee should remove their own lock and tag. Never remove someone else's lock or tag unless you are specifically authorized and trained to do so under an established procedure (e.g., when the employee who applied the lock is unavailable).
   4. Notify Affected Employees: Inform all affected employees that the equipment is about to be re-energized.
   5. Restore Energy: Follow the manufacturer's instructions to restore energy to the equipment, typically in the reverse order of the shutdown procedure.
   6. Test Operation: Carefully test the equipment's operation to ensure it is functioning correctly.

Conclusion

LOTO procedures are not just a formality; they are a vital safeguard against serious workplace injuries and fatalities. Understanding the why behind each step, and diligently following the correct procedure, is essential for ensuring the safety of yourself and your colleagues. This detailed walkthrough, combined with hands-on training and adherence to your company's specific LOTO program, will provide a strong foundation for safe and effective maintenance operations. Remember, safety is always the top priority.