What Is Lockout and Tagout? A Simple Guide to LOTO Safety
Imagine a maintenance worker repairing a machine. The machine looks switched off.
But is it really safe?
There could still be electrical energy, hydraulic pressure, compressed air, mechanical energy, heat, or stored energy inside the equipment.
If that energy is released unexpectedly, someone could be seriously injured.
This is where Lockout and Tagout (LOTO) comes in.
What Is Lockout and Tagout?
Lockout Tagout is a safety procedure used to isolate hazardous energy and prevent equipment from being unexpectedly started or energized while servicing or maintenance is being performed.
In the United States, OSHA's 29 CFR 1910.147 provides requirements for controlling hazardous energy in covered general-industry servicing and maintenance activities.
The basic concept is:
Stop - Isolate - Lock/Tag - Release Energy - Verify - Work
It sounds simple, but every step matters.
What Is Lockout?
Lockout means physically securing an energy-isolating device so it cannot be operated.
For example, an electrical circuit breaker may be switched off and secured with a circuit breaker lockout device and safety padlock.
Other common lockout equipment includes:
Valve lockouts
Lockout hasps
Cable lockout devices
Plug lockouts
Safety padlocks
Group lockout devices
The correct device depends on the machine and energy source.
What Is Tagout?
Tagout uses a warning tag to communicate that equipment must not be operated.
A tag tells employees that the equipment is under an energy-control procedure and should not be operated.
One important difference is that a tag provides a warning, while a lockout device provides physical restraint.
Under OSHA requirements, when an energy-isolating device is capable of being locked out, lockout is generally used unless the applicable requirements for tagout and equivalent protection are met.
Why Does LOTO Matter?
A machine does not become safe simply because someone presses the stop button.
For example, a hydraulic system may still contain pressure after the equipment has been shut down. A suspended component may still have gravitational energy. Electrical equipment may contain stored electrical energy.
A proper LOTO procedure identifies these hazards and controls them before maintenance begins.
8 Basic Steps of Lockout Tagout
A general LOTO process includes:
1. Prepare Identify the machine and all energy sources.
2. Notify Tell affected employees about the shutdown.
3. Shut down Stop the equipment using the normal procedure.
4. Isolate Disconnect the equipment from its energy sources.
5. Lock or tag Apply the appropriate energy-control devices.
6. Release stored energy Control pressure, electricity, mechanical movement, heat, or other residual energy.
7. Verify Confirm that the equipment is isolated and deenergized.
8. Perform maintenance Begin servicing only after the required energy-control steps are complete.
The actual procedure should always be specific to the equipment and workplace.
Where Is Lockout Tagout Used?
LOTO is commonly used in environments such as:
Manufacturing plants
Industrial facilities
Maintenance departments
Processing plants
Warehouses
Utilities
Construction and equipment servicing environments
Any operation involving hazardous energy may require careful energy-control procedures.
Common LOTO Equipment
Different energy sources require different devices.
Electrical: Circuit breaker lockouts, plug lockouts and electrical isolation devices.
Valves: Ball valve, butterfly valve, gate valve and other valve lockout devices.
Multiple workers: Lockout hasps and group lockout systems.
General isolation: Safety padlocks, tags and cable lockout devices.
E-Square Alliance supplies industrial Lockout Tagout solutions designed for different energy-isolation applications.
Final Thought
The purpose of Lockout and Tagout is simple:
Make sure hazardous energy is controlled before someone works on the equipment.
A strong LOTO program combines proper procedures, suitable lockout/tagout devices, employee training, energy isolation, and verification.
If you want a more detailed explanation of LOTO, OSHA 1910.147, hazardous energy, and the complete procedure, see the Lockout Tagout guide from E-Square Alliance.
