OSHA requires that employers establish procedures to protect workers from the release of hazardous energy, and the unexpected energization of machines and equipment. This is called a Lockout/Tagout Program (LOTO Program). The LOTO Program must protect employees from all sources of hazardous energy, including electrical, mechanical, gravity, pneumatic, hydraulic, thermal, and chemical energy.
In general a LOTO Program establishes the required practices and procedures that will be used to protect workers. This include a requirement that sources of energy be turned off and locked out, with a physical lock, to prevent energization of machines that are being serviced or maintained. In addition, in instances in which there is stored energy, moving parts may need to be physically blocked and locked to prevent the release of stored energy.
LOTO Program Overview
OSHA's standard on the Control of Hazardous Energy, 29 CFR 1910.147, gives the steps employers must take to prevent accidents associated with hazardous energy. In general, a LOTO Program should require:
- that training in LOTO be provided
- that before working on equipment, a designated person turns off the energy source
- the energy source be disconnected from the machine
- that those who will be working on the machine lock out the energy source to prevent inadvertent machine energization
- verification that the energy source has been isolated
- that stored energy is dissipated, when possible
- verification that hazardous energy cannot re-accumulate
- the employer to ensure workers have taken all necessary steps to prevent injury from the release of the stored energy
Two other OSHA standards also contain energy control provisions:
- 1910.269 - Special Industries, Electric Power Generation, Transmission, and Distribution
- 1910.333 - Electrical, Selection and Use of Work Practices
In addition, some of the OSHA standards for specific equipment include deenergization requirements. An example would be section 1910.179(l)(2)(i)(c) which requires that before performing preventive maintenance on overhead and gantry cranes, the switches controlling the crane be "open and locked in the open position."
What Does "Lock Out" Mean?
A “lock out” device physically holds an energy-isolation device in a safe or "off" position. The “lock out” device physically locks into place such that no one can remove the device except the person who applied the device. A typically example would an electrically powered machine. The source of energy is removed by opening a breaker. The breaker is locked into the off position using physical locks. Each person who will be working on the machine places their lock on the breaker, and each person has the only key that will open their lock. This ensures that one person cannot remove all the locks while another person is still working on the machine.
Other types of locking devices are applied to valves, preventing the valve from being operated while locked. There are locks for steering wheels, switches, lock boxes, and pull-chains. Whatever form the energy is in, there is a way to isolate that energy and physically lock it.
What Does "Tag Out" Mean?
At times it may not be physically possible to lock out an energy source. In those circumstances the LOTO Program will specify a tagout procedure. In tagout tags are fastened to the energy-isolating device to provide a prominent warning not to reenergize the machine while it is being serviced. However, a tag is easier to remove than a lock, and thus provides less protection.
If tagout is used on a machine that can be locked out, the employer must ensure there are additional measures in place such that workers have the same level of protection that using a lockout device would have provided.
OSHA's LOTO Program Requirements
The OSHA LOTO standard requires employers to have an energy-control program that ensures employees isolate machines from their energy sources and render them inoperative before conducting any servicing or maintenance work on the machine. In addition, the OSHA LOTO standard sets the minimum requirements that must be included in the LOTO Program. These include:
- Establish energy-control procedures for:
- disconnecting the source of energy supply from machines.
- using lockout or tagout devices on the energy-isolating devices to prevent reenergization.
- protecting workers from stored or potentially reaccumulated energy.
- Training employees on the energy-control program, including the safe application, use, and removal of energy control devices.
- Evaluating the LOTO Program on at least an annual basis to ensure the procedures are being followed and that they are still effective in preventing employees from being exposed to hazardous energy.
Within the boundaries established by the OSHA standard, employers have the flexibility to develop their own procedures that are suitable for their situation and the types of machines they work with.
When Must Lockout/Tagout Be used?
You must use LOTO whenever employees are involved in servicing or maintaining machines that expose them to hazardous energy from unexpected energization, or from the release of stored energy. There are some limited exceptions for machines that cannot be shutdown for servicing.
Some of the common methods used to prevent the release of hazardous energy include:
- manually opening a circuit breaker
- manually opening a disconnect switch
- manually closing a valve
- installing a pipe blank
- installing a safety block
Lockout requires the use of a physical lock, or another type of lockout device, to hold the energy-isolating device in a safe position, preventing the machinery from becoming energized. This cannot be an informal process. There must be specific, written procedures that are followed so that there is complete assurance the machine will not be energized until everyone who placed a lock on the energy-isolating device has removed their lock.
OSHA requires that employers develop and use written procedures describing what will be done to control hazardous energy.
In general, the written LOTO Program must
- Describe what employees need to know and do to control hazardous energy.
- Describe the circumstances when LOTO procedures apply.
- Outline the scope, purpose, authorization, rules, and techniques that are to be used to control hazardous energy.
- Specify how compliance with the LOTO Program procedures will be enforced.
OSHA requires that the written procedures provide at least the following information:
- A description of how to use the procedures.
- Specific procedural steps to shut down, isolate, block, and secure each type of machine or system.
- Specific steps designating the safe placement, removal, and transfer of lockout/tagout devices, and identifying the person responsible for the lockout/tagout devices.
- The specific requirements for testing machines and systems to verify the effectiveness of the lockout devices, tagout devices, and other energy-control measures.
What Must Be Done Before Work Starts
Before beginning to work on a machine, the following steps must be completed in sequence and according to the specific energy-control procedures established in the LOTO Program:
- Prepare for shutdown.
- Shut down the machine or system.
- Disconnect and isolate the machine or system from all energy sources.
- Apply the lockout or tagout device(s) to the energy-isolating device(s).
- Release, restrain, or otherwise render safe all stored or residual energy.
- If appropriate, install isolating devices such as pipe blocks
- If re-accumulation of hazardous energy is possible, regularly verify that energy has not re-accumulated to hazardous levels.
- Verify the isolation and de-energization of the machine.
Removing Lockout or Tagout Devices and Reenergizing
If someone removes a lock or tag, and re-energizes a machine while people are still working on the machine, someone may be seriously injured or there may fatalities. It is extremely important that only the person, who applied a lock or tag, remove that lock or tag.
Before removing a lock or tag, the following steps must be followed. The specific actions required to accomplish these steps should be in the LOTO Program procedures for the machine or system:
- Inspect the machine or system, and its components, to assure it is operationally intact and that nonessential items are removed from the area.
- Check to assure that everyone is positioned in a safe location.
After all workers have removed their lockout or tagout devices, but before re-energizing the machine, everyone who works with the machine, as well as those in the area where the work on the machine was performed, must be informed that the LOTO devices have been removed and the machine is capable of being re-energized.
LOTO Program Review
The periodic review of the LOTO Program is essentially an audit of the LOTO procedures. It involves an inspector checking to ensure employees are familiar with their responsibilities and that the specified energy-control procedures or being properly used. The person doing the review must be an authorized person who is not involved with the LOTO procedure being reviewed. The purpose of the review is to determine the following:
- Are employees following the energy-control procedures?
- Do employees know their responsibilities as define by the procedures?
- Does the procedure provide the necessary protection? If not, what changes are needed?
For a lockout procedure, the periodic inspection must include a review of each authorized employee's responsibilities under the energy-control procedure being inspected.
For a tagout procedure, the review must also include all affected employees. Affected employees are those who are not involved in the maintenance or serving work, but who use or work with the machine, system or component being tagged out. Affected employees must be able recognize tags and their meaning; know about tagout procedures; and understand that tagged out devices must not be activated.
In addition, the employer is required to certify that the designated inspectors actually performed the required inspections. This certification must specify the following:
- Identification of the machine for which the energy-control procedure was used.
- Date of the inspection.
- Names of the employees included in the inspection.
- The name of the person who performed the inspection.