LOTO - Methods of Locking Out Energy

5. Methods of Locking Out Energy


There are many different ways to lock out a piece of equipment. Commonly, the main electrical disconnect switch has one opening where a lock can be placed.  If more than one employee works on the equipment, a lockout adaptor or multiple-lock hasp, suitable for the installation of several locks must be used, enabling all workers to lock out the machine with their individual locks.  If the switches are in a metal box, the box itself must be locked out in the closed position.  If a fuse was removed in order to de-energize the equipment, the fuse box must be locked.  If the controls are in a metal covered box, a common hasp can be welded or riveted to the door, along with a lock staple. Then the switch can be "opened" and the door closed and padlocked.  Fuse boxes can also be locked in this way.  Capacitors must be safely discharged to ground with ground straps installed prior to working around, storing or transporting them

Locks and Tags on Single and Multiple Electrical Breakers
Electrical Plug Lock Box

Compressed Air/Gasses/Hydraulic Fluids/Steam/Pressurized Water
Machines activated by compressed air or steam will have valves that control movement.  These valves will need not only to be locked out, but also bled to release any residual pressure.  Physically disconnect the equipment from the supply plumbing if possible. If not possible, use double valves or blind off supply lines with appropriate flange plates or pipe caps.

Locked Comp. Air Line
Locked Globe Valve
Locked Gas Cylinder
Locked Gas Cylinder

Mechanical Energy
Blocking equipment components so they cannot move, using support rods for counterweights or elevated components, a bar through spokes of a wheel, flywheel or fan blades, a wedge-shape wheel-chalk for rolling components, etc. are all examples of blocking mechanical energy.



Steering Wheel Locking Cover
Installing a Machine Block
Wheel Chock Prevents Rolling

6. Program Requirements and Procedures

This Energy Isolation — LOTO Program includes the following Cal/OSHA required elements:

  • A survey of equipment conducted by responsible persons in each department who are thoroughly familiar with equipment operation and associated hazards, in order to identify which components and energy sources are to be locked and blocked out.
  • Identification and labeling of lockout devices for the equipment.
  • Selection and purchase of locks, tags and blocks for all employees who will be working on the equipment.
  • A standard energy isolation procedure that is followed by all personnel working on equipment.
  • Adaption of the standard Energy Isolation Procedure to a written location-specific energy isolation procedure for individual pieces of equipment.

Surveying Equipment's Energy Disconnecting Means
An initial survey of equipment specific to a department and/or work-project site is completed to identify all energy sources requiring isolation.  This is done by physical inspection, possibly in combination with a study of drawings and equipment manuals.  This survey is conducted when facilities are built / brought on line by the Project Manager with the requirements of this program integrated into project UC Berkeley Energy Isolation Program – Lock out / Tag out documentation. Completion of energy isolation surveys are provided to the host department, and signage and labels installed on energy disconnects in compliance with this program by the General
Contractor under direction from the Project Manager.  

For previously constructed facilities / equipment, this initial survey is conducted as location-need and equipment work arises.  The survey is completed by the responsible department / owner of the equipment, by PP-CS, or by the Contractor, whoever will be maintaining, repairing or adjusting the equipment needing energy isolation.  

Once each survey is complete, a list of all equipment requiring an Energy Isolation – LOTO procedure is kept by the host department and made available to anyone requiring this information to conduct safe equipment-specific energy isolation work as needed for future reference / use.  Attachment #1 is a template for developing this Equipment List.

Identifying & Labeling the Energy Disconnecting Means
For each piece of equipment identified, all energy sources are known with the corresponding disconnecting means appropriately marked indicating their function. Categorize the identification and labeling details as to equipment supplied and energy type and magnitude. 

HVAC Compressor #1, Roof, HMF Building, Electrical 480 volts, ½” line Compressed Air 100 psi.

A sign or sticker—"LOCKOUT HERE"— with accompanying information of the equipment being controlled and placed at the disconnecting location is installed to help direct workers to correct lockout devices. After surveying the equipment, additional or more practical means for energy isolation may be installed. In complicated operations, schematics of just the disconnecting means may need to be drawn up by the PP-CS engineering department.

Disconnect Panels with "Lockout Here" Label
and Energy Isolation Information

Locks, Blocks, & Accident Prevention Tags

Each worker has their own lock set and the only key to that lock set.  To maintain harmony with LBNL facility requirements, it’s suggested all locks be ‘RED’ in color to quickly identify locked / tagged energy sources.  The locks are substantial and durable, and have the name of the employee or some other uniquely identifiable marking on them.  In addition, locks may be color-coded to indicate different shifts or types of crafts. When more than one worker is servicing a piece of equipment that must be
locked out, a lockout adaptor hasp is used which allows all the workers to place their locks on the disconnecting means. After the work is completed, each worker removes their lock and the machine is then returned to service.

lock1 lock2 lock3 lock4
Typical Locks and Hasps for Use in Locking Out Equipment

lockedout locked2 lockedout3 locked4
Electrical Panels shown "Locked Out"

pipelocked1 pipelocked2 pipelocked3 pipelocked4
Piping shown "Locked Out"

Blocks, Blinds and Bleeds
Blocks are placed under raised dies, lifts, or any equipment that might inadvertently move by sliding, falling or rolling.  Blocks, special brackets, or special stands such as those commonly used under raised vehicles, are made available and always used.  Before installing blinds or blocks, steam, air, or hydraulic lines are bled down to return the system to atmospheric pressure, then blinds / blocks are installed. Coiled springs, spring-loaded devices, or suspended loads are released so that their stored
energy will not result in inadvertent movement.

flange stands
Blocking an Equipment Press
Pipe Blinding Flange
Support Stands used for Blocks


TAGS ARE NOT USED ALONE unless there is no method to safely isolate energy sources. Tags or signs are used in addition to locks. Tags or "tagout devices" are capable of enduring at least 50 pounds of pull.  Tags state the:

  • Reason for the lockout.
  • Name of the employee(s) who is/are working on the equipment.
  • How the employee who placed the tag may be contacted.
  • Date and time the tag was put in place.


Rules for Using Energy Isolation - LOTO Procedure
Several basic safety rules are applied during every energy isolation situation.  These are:
1. All equipment shall be blocked and locked out to protect against accidental or inadvertent
operation when such operation could cause injury to personnel.

2. Never attempt to operate any switch, valve, or other energy isolating device bearing a lock.

3. Never remove a blocking device until all personnel, tools and obstructions have been cleared
from the area, and all equipment guards have been properly reinstalled.

4. If the equipment or system must remain energized during work, contact the Office of
Environment, Health & Safety (EH&S) Safety Engineering to assist in developing adequate
alternative hazard control measures, such as the use of suitable temporary barriers, special
tools and personal protective equipment.

Standard Energy Isolation  LOTO Procedure

1. All maintenance personnel are issued a suitable lock (or locks for multiple energy sources). Each lock has the individual worker's name or other identification on it. Each worker has the only key to the lock / lock set.

2. The worker checks to be sure that no one is operating the machinery BEFORE turning off the power.  The machine operator and project supervisor is informed before the power is turned off because unexpected sudden loss of power could cause an accident.

3. Steam, air, and hydraulic lines should be bled, drained, and cleaned out.  There should be no pressure in these lines or in reservoir tanks.

4. Any mechanism under load or pressure, such as springs, should be released and / or blocked.

5. Each person who will be working on the machinery should put a lock on the machine's lockout device(s). Each lock must remain on the machine until the work is completed.  Only the worker who placed the lock should remove their lock.

6. All energy sources which could activate the machine must be locked or blocked out.

7. The main valve or main electrical disconnect must be tested to be sure that the power to the machine is off.

8. Electrical circuits must be checked by qualified persons with proper and calibrated electrical testing equipment.  Stored energy in electrical capacitors should be safely discharged.

9. CAUTION: Return disconnects and operating controls to the "off" position after each test.

10. Attach accident prevention tags which give the reason for placing the lock/tag, the name of the person placing the lock/tag, how they may be contacted, and the date and time the lock/tag was placed.

Testing/Adjusting Equipment during Lockout
In many maintenance and repair operations, machinery must be tested and therefore energized before additional maintenance work can be performed. For such situations, this procedure must be followed:

1. Clear all personnel to safety.

2. Clear away tools and materials from equipment.

3. Remove lockout devices and re-energize systems, following the established safe procedure.

4. Proceed with tryout or test.

5. Shut off all energy sources once again, purge all systems, and lockout energy sources prior to continuing work.

Equipment design and performance limitations may dictate that effective alternative worker protection be provided when the established lockout procedure is not feasible. If machinery must be capable of movement in order to perform a maintenance task, workers must use extension tools, personal protective equipment and other means to protect themselves from moving parts and potential injury.

Restoring Equipment to Service
After the work is completed and the equipment is ready to be returned to normal operation, this procedure must be followed:

1. Remove all non-essential items.

2. See that all equipment components are operationally intact, including guards and safety devices.

3. Repair or replace defective guards before removing locks.

4. Remove each lockout device using the correct removal sequence.

5. Make a visual check before restoring energy to ensure that everyone is physically clear of the equipment.

Each lock is removed by the authorized employee that applied it, or under his/her direct supervision. If the authorized employee is absent from the work place, then the lock or tag can be removed by a qualified person designated to perform this task provided that the immediate supervisor:

1. Verifies that the authorized person is not present and therefore unable to remove the lock;

2. Makes all reasonable efforts to inform the authorized employee that the lockout/tagout device has been removed; and

3. Ensures that the authorized person knows the lockout/tagout device has been removed before work resumes.


Location Specific Energy Isolation Procedures
Use the attached check list (Attachment #2) to prepare a written sequence for access, de-energizing, lockout, testing, and start-up of equipment requiring energy isolation under this program. 

When tail-gating / training for an equipment-specific lockout procedure, consider:
• All workers must understand what equipment energy isolation – LOTO means.
• The Project Supervisor must be trained in this written procedure and fully knowledgeable of
hazardous energies specifically related to the equipment.
• Employees reassigned to different equipment must be trained on that specific equipment.
• Contractors working on site must have knowledge of the Energy Isolation – LOTO program
and follow UC Berkeley’s equipment-specific Energy Isolation – LOTO procedures when they
have been previously developed.

control panel

Location-Specific Energy Isolation Procedure shown in file on front of Equipment Control Panel

Joint Projects

If University personnel and contractor personnel are working on the same piece of equipment, then the University provides the hasps that the University personnel installs their locks on, and the Contractor provides their hasps that their personnel installs their locks on. Each work team installs their own hasp and locks on each energy source.

7. Training Requirements

All persons identified in the “Roles / Responsibilities” section of this program must receive documented training on their required work practices in application of this program.  Initial training is given by EH&S within 3 months of program adoption for all current personnel, and within one month upon new hire.  Update training on this program is to be given whenever this program changes, if it’s application to specific equipment changes, or if host department operations or equipment / energy hazards change such that personnel must have retraining to conduct safe work.

8. Record Keeping Requirements

DSC keeps training records of all department personnel trained on this program.  Training records include the name of the person trained, date of training, an outline of training content, and a signature of the trained individual.  Records are kept for the duration of the person’s employment at UCB plus 3 years.

DSC keeps an up-to-date Equipment Survey List (Attachment 1) of all department-controlled equipment that falls under requirements of this program.  Survey lists are available for review by EH&S, and use by PP-CS and other departments or contractors who may need access to the list for planning and tail-gating safe work practices.

DSC provides blank templates of Energy Isolation – LOTO Procedure Checklist Forms (Attachment 2) to responsible persons within the department for creation of “Equipment Specific” Energy Isolation Procedures.  Completed Energy Isolation – LOTO Procedure Checklists are kept on file by the DSC, with copies provided to EH&S for inclusion in a campus Energy Isolation – LOTO Procedure Checklist database.  DSC provides an Energy Isolation – LOTO Procedure Checklist for a specific piece of
equipment to any UCB staff, personnel or outside contractor conducting work on or around such equipment upon request.

9. References

 The following Title 8 Cal/OSHA codes are referenced in this program:

  • 3314. The Control of Hazardous Energy for the Cleaning, Repairing, Servicing, Setting-Up, and Adjusting Operations of Prime Movers, Machinery and Equipment, Including Lockout/Tagout  http://www.dir.ca.gov/title8/3314.html

10. Issued by

UC Berkeley EH&S — April 1, 2009

Next Review Date: January 1, 2012 or sooner upon changes to code requirements.


  1. Template – Equipment Inventory and Energy Isolation Procedures Tracking/Audit Log
  2. Template – Equipment-Specific Energy Isolation Procedure

Lock Out / Tag Out