A lockout/tagout program involves establishing written procedures for isolating machines and equipment from energy sources, and affixing locks or and/tags to the energy isolating devices. The purpose of lockout/tagout is to prevent worker injuries and fatalities caused by unexpected start-up or release of stored energy during repairs, maintenance, cleaning, and operation of machinery.

The primary elements of an effective lockout/tagout program include:

• Equipment Shutdown
• Locking or tagging the energy-isolating device(s)
• Release of stored energy
• Verification of isolation

Lockout/tagout is not complete until the locks and/or tags are removed in accordance with established procedure.

WRITTEN PROGRAM

A formal written lockout/tagout program should be developed and implemented. The following elements should be well defined in the written program:

• Statement on when/how lockout/tagout procedures will be implemented
• Steps to shut down, isolate, block and secure specific pieces of equipment
• Procedure for placing, removing, and transferring lockout devices (and who has responsibility for them)
• Specific requirement for testing machines or equipment to verify the effectiveness of locks and other energy control measures

LOCKOUT

Machines and equipment requiring lockout should be identified and checked to see if there is an effective energy-isolating device for all (electric, hydraulic, pneumatic, steam, etc.) power sources leading to each machine. An energy-isolating device is a durable and standardized physical device that prevents transmission or release of energy. Examples include:

• Manually operated circuit breakers or switches
• Disconnect switches
• Pneumatic, hydraulic, or steam valves
• Safety blocks

Examples of when lockout procedures are required include machinery repair, overhaul, or maintenance it that machine has:

• Electrical, hydraulic, or pneumatic power sources
• Gas, steam, or other pipeline systems or pressurized storage tanks
• Stored energy sources, such as raised machinery, springs, etc.

Lockout should also be used during preventive maintenance tasks such as lubrication, cleaning, adjustment, and unjamming of equipment if the worker is required to:

• Remove or bypass machine guards or other safety devices
• Place any part of the body in contact with hazardous machine parts
• Place any part of the body into a danger zone during a machine cycle

Procedures for lockout should include:

• Verify that workers can easily reach and operate switches and valves. Relocate any switches or valves that require awkward reach or ladders to engage/disengage.
• Label switches and valves to clearly identify which machines or equipment they control. Symbols and/or bilingual wording my be appropriate to communicate the necessary information to workers.
• Issue key-actuated padlocks to each person with lockout responsibility. No two locks should be operated by the same key. Identify each lock with the assignee’s name, ID number, and department or trade for identification.
• Every employee who is working on a machine should place his or her lock on the switch or valve. Lockout adapters that hold several locks should be available to each person.
• Cables or chains may also be needed to secure large valves in the closed position.

TESTING

After confirming that no workers are in dangerous locations, the machine should be engaged using push buttons or other normal starting controls to verify that the equipment will not operate.

OTHER SOURCES OF ENERGY

Pressurized air, oil, or other fluids can present significant hazard until pressure is released. Accumulators and air surge tanks should be reduced to atmospheric pressure and pressure should not be allowed to re-accumulate.

Loose or freely moveable machine parts should be secured. Rams or slides that can move should be mechanically secured using blocks.

Springs in tension or compression should also be considered as stored energy sources and protected appropriately.

LOCK REMOVAL

The only employee who should remove the lock is the one who installed it. Authorized personnel should visually inspect the area before power is restored to ensure that all workers are clear of the equipment and work has been completed properly.

The following guidelines are suggested for lock removal:

• Do not rely on pulling fuses as a substitute for placing a lock in the energy-isolating device. A pulled fuse does not guarantee that the circuit is dead nor does it prevent someone for replacing it and re-energizing the machine.
• Do not relay on locking out operating controls (START button instead of the power sources (main breaker).
• Do not assume that the job is too small to require lockout.
• If a locked-out job is not completed by the end of the shift, workers going off duty should not remove their locks until those on the next shift have attached theirs.
• Establish and enforce written procedures for safely working on machines and equipment. Guidelines should apply to major and minor repairs.

TAGOUT

Using tags alone is not an effective measure against unexpected start-up of machines and equipment. Problems associated with tag use include:

• Tags may fall off
• Someone could remove the wrong tag
• Workers might forget to use a tag
• People might ignore the tag

Tags may be used with locks as a supplemental information aid. Information explaining what equipment is locked out, by whom, and for what purpose can be helpful.

TRAINING

All employees should be provided initial and ongoing training in lockout/tagout procedures so that they fully understand the program’s objectives and procedures and their own responsibilities. New hires and transfers should be included in the training program. Workers should be trained at any time there is a change in machines, equipment, processes, or energy control procedures. All training should be documented in writing to indicate who received the training, who conducted the training, the content of the training, and the date.

Employers and contractors must inform each other of lockout/tagout programs to ensure coordination of efforts.