What Is Lockout/Tagout?

Lockout/tagout (LOTO) is the practice of disabling, isolating, and securing hazardous energy, while also providing information about the worker and the work taking place.

By identifying hazardous energy sources and their isolation points, LOTO procedures provide a guarantee to workers that the locked out equipment or area will remain de-energized, deactivated, or inoperable while their they are completing their tasks.

A hasp and lock provide a physical barrier to reactivating or re-energizing the equipment, while a tag serves as a visual prompt to notify workers of the shutdown or isolation. These tags should provide the name and contact information of the person who has applied the lock, and it can also include a brief summary of the work that is taking place.

What Do Construction Companies Need to Know About LOTO?

Isolating Kenetic and Potential Energy

There are two encompassing forms of energy prevalent in the construction industry: kinetic and potential.

Kinetic energy sources include:

  • Electrical
  • Thermal
  • Radiant
  • Sound

Potential energy sources include:

  • Chemical
  • Suspended
  • Pressurized
  • Magnetic
  • Mechanical

No matter the form of energy, the risks remain the same. When not properly identified, communicated, and controlled, the release of energy can be catastrophic to the workers or the public.

Due to the potentially devastating effects of an unplanned release of energy, isolating devices that physically prevent the conveyance or release of energy are available and regularly used on construction sites. Some examples of these isolating devices are:

  • Manually operated circuit breakers and disconnect switches
  • Manually operated switches conductors can use to disconnect from all supply sources
  • Line valves, blocks, and other devices that can stop or isolate energy

Conducting the Risk Assessment

With multiple trades, schedules, priorities, and deadlines, construction is a very complex industry. This makes implementing an effective and successful lockout/tagout program more challenging.

Because there is so much complexity, the preliminary risk assessment that leads to the creation and implementation of a LOTO procedure must be conducted by the general contractor.

All energy sources should be identified and a concise isolation or shut-off procedure written for each of them. Employees and subcontractors alike must be trained in the procedure.

A written procedure creates the structure and culture required to ensure the proper sequence of de-energization and provides assurance that all equipment, machines, or system components remain inoperable until all work is complete.

Lockout/Tagout Procedure: Basic Steps

Here are some common and effective procedural steps for lockout/tagout.

Step 1: Identify All Equipment and Energy Sources

Examine your work areas to identify the equipment, machinery, and system components within them. Assess them to determine which sources of energy are used during their operation or if any residual energy results from their operation.

Consider electrical, steam and water, momentum, gravity, pneumatic, and hydraulic energy.

Step 2: Personnel Notification

Shutting down and locking out equipment can affect multiple groups of people who work on the site. Because of this, an unexpected interruption of power or energy can have adverse effects on production and safety. Your LOTO procedure should provide a list of key points of contact on the construction site and the method for communicating the specifics of any upcoming shutdowns to everyone on site.

Step 3: De-energize and Stop All Operations

Next, all equipment, machinery, or system components must be shut down and placed in a state of zero energy.

This shutdown procedure should be completed by a qualified worker who is able to verify the complete isolation of any system redundancy and potential stored energy.

Step 4: Apply Lock and Tag

After the circuit has been de-energized, inspect all parts and attachments to ensure they are secured. Once you have confirmed that everything is isolated and potential energy has been released, it's time to apply locks.

Remember, even though the disconnect, valves, breakers, or switches are in the "off" position, you are not protected until you have attached your own personal safety lock.

Once the lock has been applied, it must be tagged. Tags should be visually conspicuous while remaining secured against inadvertent removal. Tags must identify the worker’s name and contact information, the worker’s employer, and the date and reason for the lockout.

Tags must be made of non-conducting material and able to remain legible through varying weather and terrain conditions.

Step 5: Release from Lockout

Before restoring energy to the equipment, the area must be assessed to determine the following:

  1. The work is complete and all personnel have cleared the work area
  2. All parts and safeties are properly in place, with the machine operationally intact
  3. All tools, equipment, and materials used during the work are removed from the area

Once these items have been confirmed, you can begin the lock removal sequence.

If there is a group lockout in place, workers can start removing their locks one at a time. Once the final lock is removed and all work areas confirmed as clear, energy can be restored.

Additional Procedure Elements

In addition to the steps above, your procedure should also include:

  • Training requirements for workers and subcontractors
  • Types of lockout equipment and devices that are required for the project
  • Quality and standards for the lockout devices
  • Color, shape, size, and material type for the tags
  • Information required to be communicated on the tags

Group Lockout

With many tradespeople on construction sites, it's quite common for multiple people to lockout an energy source.

Group lockout provides an effective way for several workers to secure an energy source while also reducing the amount of time required to establish a lockout. Appointing a few key individuals to install locks on the energy isolation points and then placing their keys inside a lockable box can make the lockout process less cumbersome.

Keep Hazards Controlled

The construction site can be a dangerous place. Having a comprehensive lockout/tagout procedure is an important step to making sure the hazards present on site don't result in an accident or injury.