OSHA Lockout / Tagout (LOTO) 1910.147

Why this matters

OSHA's Control of Hazardous Energy Standard (29 CFR 1910.147 - commonly "LOTO") is the federal safety standard for ANY service work that involves a power source that could re-energize. It applies to electrical, gas, hydraulic, pneumatic, mechanical-stored-energy (springs, falling objects) - virtually every trade. LOTO violations are among the most-cited OSHA general-industry standards every year. Serious or willful violations following an injury can shut down a business. Every trade tech needs LOTO awareness; supervisors need formal training + a written program.

Who LOTO covers

OSHA's 1910.147 applies whenever:

• Service or maintenance of equipment requires bypass of safety guards
• The unexpected energization could injure a worker
• The work could not be done safely under normal "alive" conditions

This is broader than electrical work. Examples:

• Replacing a fan blade in a gas furnace (electrical + risk of unexpected fan start)
• Servicing a hydraulic lift (stored hydraulic pressure)
• Working on a garage door spring (stored mechanical energy)
• Repairing a pool pump (electrical + stored pressure)
• Replacing a refrigerant component (refrigerant pressure)

LOTO is NOT just "turn off the breaker." It's a documented procedure with verification.

The 7 steps (the standard procedure)

OSHA's 1910.147 requires these documented steps for any LOTO event:

Step 1: Preparation

• Identify ALL energy sources (electrical, gas, hydraulic, pneumatic, thermal, gravity, mechanical, water)
• Document each source + its means of isolation
• Identify all employees who'll be affected
• Notify them

Step 2: Shutdown

• Power down equipment per normal procedure
• All sources of energy turned off in correct sequence

Step 3: Isolation

• Physically disconnect each energy source at its isolation point
• Electrical: circuit breaker OFF + locked
• Gas: valve closed + locked
• Hydraulic: valve closed + locked
• Pneumatic: valve closed + locked

Step 4: Lockout / Tagout

• Apply a LOCK to each isolation point (lockout)
• Apply a TAG identifying the worker + reason for isolation (tagout)
• One lock per worker per energy source (each worker uses their own padlock)
• Lock + tag must be approved type (NOT a personal padlock from home; specifically rated devices)

Step 5: Release stored energy

• Capacitors discharged
• Springs released or blocked
• Hydraulic pressure bled off
• Pneumatic pressure released
• Gravity-stored objects supported or lowered
• Thermal: allow to cool

Step 6: Verification

• Attempt to start the equipment (push the start button, throw the disconnect)
• Confirm it does NOT energize
• Test all controls
• Use multimeter to confirm no voltage on the work item
• Return controls to OFF after verification

Step 7: Performing service

• Now perform the service work
• Maintain locks + tags throughout
• If multiple workers, each maintains their own lock

Restoring power (the often-skipped step)

After service is complete:

1. Inspect the work area; verify tools + parts removed
2. Confirm guards + covers restored
3. All workers clear of the equipment
4. Notify affected workers
5. Remove locks + tags (each worker removes only their own)
6. Re-energize per normal startup procedure
7. Verify normal operation

NEVER let one worker remove another worker's lock. The exception is rigidly controlled - supervisor with documented certification that the worker is unavailable + has not returned.

Group lockout

Multiple workers on a job? Group lockout protocol:

• Group lockbox at the isolation point
• Key to each isolation lock placed in the box
• Each worker locks the box with their own lock
• Service performed only while all locks in place
• Each worker removes their lock when leaving the job
• Last worker out triggers restoration

This is the only legitimate way to handle multi-worker LOTO.

Documentation requirements

OSHA requires (for inspection):

• Written LOTO program for the employer
• Documented procedure for each piece of equipment OR equipment type
• Training records for each affected employee
• Periodic inspection (annual) of LOTO procedures

For a small contractor, this is a one-time program with annual review. For a larger contractor, it's a meaningful HR + ops investment that pays back in safety culture + insurance pricing.

Common LOTO violations (the citations)

• "Turn off the breaker" with no lock applied
• Lockout but no verification (didn't test that equipment is dead)
• Personal lock instead of LOTO-approved
• Cross-utility lockout (locked electrical but didn't lock gas)
• Permitting another worker to remove your lock
• No documented program in the office
• No training records

Each is an OSHA citation worth + per violation.

Industry-specific LOTO scenarios

HVAC

• Disconnect on outdoor unit OFF + locked
• Indoor air handler breaker OFF + locked
• Capacitor discharged before touching contactor
• Refrigerant pressure released through service ports OR recovery

Plumbing

• Water supply valve closed + locked OR drained
• Gas supply valve closed + locked
• Electrical to pump OFF + locked (well + tankless water heater pumps)

Electrical

• Breaker OFF + locked + tagged
• Verify with voltage tester before touching
• Capacitors discharged (motors, microwaves, lighting ballasts)

Garage door

• Spring de-tensioned + winding bars in place OR door clamped open
• Power to opener disconnected + locked
• Lift cable secured

Appliance

• Power unplugged AND breaker OFF + locked (water + power loss can re-trigger)
• HV capacitor in microwave discharged

Pool service

• Pump breaker OFF + locked
• Salt cell power off
• Heater gas + electric off

Training

OSHA requires:

• Authorized employees (those who perform LOTO + service): comprehensive training. Recognition of energy sources, isolation methods, written program review.
• Affected employees (those whose work area includes LOTO equipment): training on recognition of LOTO devices + not to attempt restart.
• Other employees: awareness of LOTO existence + reason for tags / locks they may encounter.

Refresher training when:

• Job assignment changes
• Equipment changes
• New procedures
• Periodic inspection finds deficiencies

Tools

• Approved LOTO padlocks (each tech carries 6 - 12 colored padlocks; color-coded to tech)
• LOTO tags (numbered + dated)
• Group lockout boxes
• Insulating gloves for electrical verification
• Voltage tester / multimeter
• Capacitor discharge tool (for HV work)
• LOTO procedures binder OR digital system

References

• OSHA 29 CFR 1910.147 (Control of Hazardous Energy)
• OSHA Compliance Directive CPL 02-00-147
• ANSI Z244.1 (lockout / tagout)
• Manufacturer service manuals (equipment-specific isolation)
• Manuall internal: OSHA Quick Reference for Field Work, Job-Site Safety Checklist