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Lock Out Tag Out (LOTO) Procedures

Introduction

Lock Out Tag Out (LOTO) is a critical safety procedure designed to protect workers from the unexpected energization or startup of machinery and equipment during maintenance or repair activities. LOTO violations are the leading cause of electrical injuries in the workplace, making proper understanding and implementation of these procedures essential for worker safety.

LOTO procedures must be used whenever:

  • Performing maintenance or repair work on electrical equipment
  • Cleaning or servicing machinery with moving parts
  • Clearing jams or blockages in equipment
  • Installing or modifying electrical systems
  • Any work where unexpected energization could cause injury

Failure to follow LOTO procedures can result in serious injury, death, or equipment damage.

LOTO Fundamentals

Definition

Lock Out: The placement of a lock on an energy isolation device to ensure that the device cannot be operated until the lock is removed.

Tag Out: The placement of a tag on an energy isolation device to indicate that the device should not be operated until the tag is removed.

Purpose

The primary purpose of LOTO is to prevent the unexpected energization, startup, or release of stored energy during maintenance and repair activities. This protects workers from:

  • Electrical shock and electrocution
  • Burns from arc flash and thermal hazards
  • Crushing injuries from moving machinery
  • Cuts and amputations from unexpected equipment startup

OSHA Standard 1910.147 "The Control of Hazardous Energy" mandates that employers establish LOTO procedures for all equipment maintenance and repair activities. Key requirements include:

  • Written energy control procedures
  • Employee training on LOTO procedures
  • Periodic inspections of LOTO procedures
  • Use of standardized locks and tags

Injury Statistics

According to OSHA data:

  • Failure to control hazardous energy accounts for nearly 10% of serious industrial accidents
  • Approximately 120 fatalities occur annually due to failure to LOTO
  • Over 50,000 injuries per year are attributed to inadequate energy control
  • Electrical incidents account for 40% of LOTO-related fatalities

Step-by-Step LOTO Procedure

Step 1: Notify Affected Personnel

Before beginning LOTO procedures:

  1. Inform all personnel working in the area of the planned maintenance
  2. Notify operations supervisors and control room personnel
  3. Post notices if work affects multiple areas or shifts
  4. Ensure all affected personnel understand the scope and duration of work

Step 2: Identify All Energy Sources

Thoroughly identify every energy source that could affect the equipment:

  • Electrical: Main power, control circuits, UPS systems, capacitors
  • Mechanical: Springs, compressed air, hydraulics
  • Thermal: Steam, hot fluids, heated surfaces
  • Chemical: Pressurized gases, stored chemicals
  • Gravitational: Suspended loads, elevated components

Use equipment drawings, schematics, and P&IDs to ensure no energy source is missed.

Step 3: Shut Down Equipment Properly

  1. Follow the normal shutdown sequence for the equipment
  2. Allow equipment to reach a safe state (stopped, cooled, depressurized)
  3. Do not force or emergency stop equipment unless necessary
  4. Document any abnormal conditions observed during shutdown

Step 4: Isolate Energy Sources

Physically disconnect and isolate all identified energy sources:

  • Open electrical disconnects and circuit breakers
  • Close and lock valves for steam, compressed air, and hydraulics
  • Block or secure mechanical energy sources
  • Discharge or block stored energy systems
  • Remove fuses where appropriate

Each isolation point must be physically accessible and clearly identifiable.

Step 5: Apply Locks and Tags

  1. Each worker applies their own personal lock and tag
  2. Attach locks to prevent operation of isolation devices

  3. Apply tags adjacent to locks with required information:

    • Worker's name and signature
    • Date and time of application
    • Reason for LOTO
    • Expected duration of work

  4. Use hasps for multiple locks when multiple workers are involved

  5. Ensure locks cannot be easily cut or removed

Step 6: Release Stored Energy

After isolation, safely release any stored energy:

  • Discharge capacitors using appropriate grounding procedures
  • Release compressed air and hydraulic pressure
  • Lower suspended loads or provide adequate support
  • Allow hot surfaces to cool to safe temperatures
  • Vent pressurized systems safely

Always use appropriate PPE during stored energy release.

Step 7: Verify Zero Energy State

Critical Step: Test and verify that equipment is truly de-energized:

  1. Use appropriate testing equipment (multimeters, voltage detectors)
  2. Test on a known energized source first to verify tester operation
  3. Test all conductors and components that could be energized
  4. Test tester again on known energized source after testing
  5. Attempt to start equipment using normal controls (should not operate)
  6. Document verification results

Never skip verification - this is where most LOTO failures occur.

Step 8: Perform Work

With energy sources locked out, tagged, and verified:

  1. Proceed with planned maintenance or repair work
  2. Maintain situational awareness throughout the work
  3. Do not bypass or remove LOTO devices during work
  4. Report any unexpected energy sources discovered during work

Step 9: Remove LOTO (Restoration)

CRITICAL: Follow this sequence exactly:

  1. Clear the work area - Remove all tools, equipment, and personnel
  2. Reinstall guards and safety devices - Ensure all protective equipment is in place
  3. Inspect the work area - Verify work is complete and area is safe
  4. Notify affected personnel - Warn that equipment will be re-energized
  5. Remove tags first - Each person removes only their own tags
  6. Remove locks - Each person removes only their own locks
  7. Restore energy - Follow proper energization sequence
  8. Test equipment operation - Verify proper operation before returning to service

Only the person who applied a lock may remove that lock.

Lock and Tag Requirements

Individual Responsibility

  • Each worker must apply their own personal lock
  • Locks must be unique to each individual (different keys)
  • Workers must retain their keys at all times during LOTO
  • Only the worker who applied a lock may remove it

Tag Content Requirements

All tags must include:

  • Worker's full name and legible signature
  • Date and time of application
  • Reason for LOTO (brief description of work)
  • Expected completion date/time
  • Emergency contact information

Group Lockout Procedures

When multiple workers are involved:

  1. Designate a qualified person as the group LOTO coordinator
  2. Coordinator applies primary LOTO to energy sources
  3. Each worker applies individual lock to group lockbox or hasp
  4. Each worker receives key to lockbox containing energy isolation keys
  5. Work cannot begin until all workers have applied their locks
  6. Work cannot be completed until all workers remove their locks

Lock Specifications

  • Locks must be substantial enough to prevent accidental removal
  • Locks must be standardized within the organization
  • Different lock colors may be used to identify different work groups
  • Locks must be resistant to environmental conditions
  • Master keys for LOTO locks are strictly controlled

Common LOTO Violations

1. Using Someone Else's Lock

VIOLATION: Applying or removing another person's lock or tag.

CONSEQUENCES: Immediate disciplinary action, potential termination.

CORRECT PRACTICE: Each person applies and removes only their own LOTO devices.

2. Removing Another Person's Lock

VIOLATION: Cutting, unlocking, or removing another worker's lock without proper authorization.

CONSEQUENCES: Immediate termination, potential criminal charges.

CORRECT PRACTICE: Only emergency removal procedures may authorize lock removal by someone other than the applicator.

3. Working Without Verifying Zero Energy

VIOLATION: Beginning work without proper testing and verification of de-energized state.

CONSEQUENCES: Serious injury risk, disciplinary action.

CORRECT PRACTICE: Always test with appropriate instruments and document verification results.

4. Failing to Identify All Energy Sources

VIOLATION: Incomplete energy source identification leading to exposure to unexpected hazards.

CONSEQUENCES: Serious injury or death from uncontrolled energy.

CORRECT PRACTICE: Use drawings, schematics, and experienced personnel to identify all energy sources.

5. Not Releasing Stored Energy

VIOLATION: Failing to discharge capacitors, release pressure, or neutralize stored energy.

CONSEQUENCES: Injury from unexpected energy release during work.

CORRECT PRACTICE: Systematically identify and safely release all stored energy before work begins.

Special Situations

Shift Changes

When LOTO extends across shift changes:

  1. Incoming shift personnel must apply their own locks
  2. Outgoing shift personnel may only remove their locks after incoming shift has applied theirs
  3. Conduct formal shift turnover briefing including LOTO status
  4. Document all lock transfers and personnel changes
  5. Verify continued isolation effectiveness

Multiple Energy Sources

For complex equipment with numerous energy sources:

  1. Create detailed LOTO checklist specific to the equipment
  2. Assign isolation tasks to qualified personnel
  3. Use group LOTO coordinator to manage the process
  4. Verify each isolation point independently
  5. Document completion of each isolation step

Contractors and LOTO

When contractors work on facility equipment:

  1. Contractors must follow facility LOTO procedures
  2. Provide contractor training on facility-specific requirements
  3. Facility personnel must verify contractor LOTO competency
  4. Facility retains responsibility for energy source identification
  5. Coordinate contractor and facility LOTO activities

Emergency Removal Procedures

LOTO devices may only be removed by someone other than the applicator when:

  1. The person who applied the lock is not available
  2. A genuine emergency exists that requires immediate equipment operation
  3. All of the following steps are completed:
    • Verify the person who applied the lock is not at the facility
    • Attempt to contact the person who applied the lock
    • Verify that work protected by LOTO is complete
    • Ensure all personnel are clear of equipment
    • Management authorization at department head level or higher

Emergency removal must be documented with justification and approvals.

Important Warning

⚠️ CRITICAL SAFETY WARNING ⚠️

Attempting to disable, circumvent, or improperly remove Lock Out Tag Out devices is grounds for immediate termination. This includes:

  • Cutting locks without proper authorization
  • Removing tags prematurely
  • Working on equipment without proper LOTO
  • Bypassing energy isolation devices
  • Using unauthorized keys or tools to defeat LOTO

These actions endanger not only yourself but also your coworkers and may result in serious injury or death.

If you discover missing, damaged, or improperly applied LOTO devices:

  1. STOP work immediately
  2. Clear the area of all personnel
  3. Report to supervision immediately
  4. Do not proceed until proper LOTO is verified

When in doubt, STOP and ask for help. No job is so urgent that it cannot be done safely.

Summary

LOTO procedures are fundamental to electrical and industrial safety. Remember the key principles:

  • Every person applies their own lock and tag
  • Always verify zero energy before work begins
  • Only remove your own locks and tags
  • When in doubt, STOP and get help

Proper LOTO implementation protects lives, prevents injuries, and ensures compliance with safety regulations. Take these procedures seriously - your life and the lives of your coworkers depend on it.