Lockout/tagout (LOTO) is a safety protocol that establishes minimum requirements for identifying and blocking hazardous energy during the maintenance or servicing of industrial equipment or systems.

A lockout device is applied to physically prevent the transmission of energy. A tag or label is then attached to the lockout device to identify the authorized worker responsible for the lockout, the date and time of the lockout, and any pertinent visuals and safety information.

The best form of lockout is a physical barrier or gap, such as removing cables or installing a blind flange to eliminate any chance of danger. The least effective form of LOTO is a simple warning tag. Tagging out by itself is not recommended and is used only when it is impossible to lock out the energy source. Tags used without a lockout can require additional measures, such as physically blocking the control switch.

Types of Hazardous Energy

Hazardous energy refers to any energy that has the potential to cause injury or damage, including electrocution, burns, asphyxiation, and death.

The most common forms of hazardous energy are electrical, chemical, thermal, pneumatic, and mechanical.

Why Lockout/Tagout for Chemical Plants Is Different

Implementing LOTO in chemical plants is focused on isolating energy in the processing and piping system, using bank flanges and slip blinds. A chemical plant LOTO deactivates process systems and emphasizes the de-pressurization of the piping network and removal of all contents.

All lockout devices used in this procedure must be standardized, documented, and clearly identifiable. Many petrochemical plants augment their LOTO procedure with a work permit system that identifies the equipment to be serviced and any procedures specific to the equipment, system, or chemicals involved.

(Learn about Lockout/Tagout in Manufacturing.)

A simple LOTO procedure for pressurized liquids and compressed gasses requires:

  • Shutting off and locking out either with built-in devices or peripheral attachments
  • Tagging valves
  • Bleeding off excess gas and liquids
  • Clearing lines

Hazardous energy control procedures for chemical plants require specific LOTO protocols in comparison to lockout actions related to other equipment and machinery.

10 Steps to Ensuring a Successful Chemical Plant LOTO Procedure

1. Ensure Workers Have Proper LOTO Training

Provide LOTO training to employees, including mock drills to simulate particular situations. Ensure that the procedures and lockout devices are documented.

2. Understand the Scope and Risks of LOTO Procedures

Determine the task at hand, staff requirements, and risks involved.

3. Establish Effective Communication

Notify all affected employees that the piping network and process system is being serviced or maintained and that LOTO procedures are in place.

4. Deactivate and Remove Content from the Process System

Provide a specific lockout procedure for each type of maintenance or potential emergency, including a checklist of lockout points.

5. Outline the Responsibilities of Authorized Workers

Use a system of worker-assigned locks, including bland flanges and slip blinds. Tags must be securely attached to all lockout points, clearly indicating deactivation, danger, and do-not-operate instructions. It is crucial that all lockout/tagout resources identify the responsible worker and supervisor.

6. Isolate the System to Be Serviced

Once the processing system or piping network has been isolated and locked out, an attempt to restart the equipment should take place to confirm that there are no secondary sources of energy. Qualified personnel must verify that all energy is locked out of the system.

7. Release All Stored Energy

Ensure that all stored energy is released or neutralized, including electrical, pressure, fluids, gas, and mechanical. After all tags and locks are installed, the equipment and systems should be tested to make sure they are no longer in operation. All gases and fluids in isolated piping networks and process systems should be depressurized, emptied, and decontaminated.

8. Establish LOTO Protocols for Shift Changes

Notify all affected workers and provide specific instructions in the event of a shift change while equipment is still locked out. Substitute locks belonging to a leaving shift with the locks of the arriving shift.

9. Adapt LOTO Protocols with Changes in Operation

As system operation procedures change over time, it will be necessary to evolve your LOTO procedures alongside them.

10. Specify LOTO Restart Procedures

Make sure there are specific steps in place to recommission the piping network and process system. Include protocols that outline a process for the removal of tags and locks, and that startup is supervised by qualified personnel.

(Find out who's allowed to unlock equipment that's been locked and tagged out.)

Lockout/Tagout Makes a Difference

The OSHA standard for The Control of Hazardous Energy (Lockout/Tagout) 29 CFR 1910.147 provides the flexibility to suit the particular energy control needs of the specific equipment and industry.

According to OSHA, the successful implementation of lockout/tagout procedures in accordance to this standard prevents more than 100 deaths and 50,000 injuries annually. OSHA also points out that workers injured from hazardous energy sources are away from the job for an average of 24 days recuperation. This alone makes LOTO an essential component of any industrial safety program.