7.3 OSHA Safety: Lockout/Tagout

7.3 OSHA Safety: Lockout/Tagout (LOTO)

The Lockout/Tagout (LOTO) standard, defined by OSHA 1910.147, covers the servicing and maintenance of machines and equipment in which the unexpected energization or start-up of the machines or equipment, or release of stored energy, could harm employees. In a water distribution system, this involves pumps, valves, electrical panels, and chemical feed systems. Proper LOTO procedures are vital to prevent amputations, electrocutions, and crushing injuries.

The Purpose of Lockout/Tagout

The primary goal of LOTO is to establish a "zero energy state." This means that all potential sources of hazardous energy have been isolated, neutralized, and physically prevented from being restored while work is being performed.

Hazardous energy is not just electrical. It includes:

• Electrical: Motor control centers, breaker panels.
• Mechanical: Moving parts like pump impellers.
• Hydraulic/Pneumatic: Pressurized fluids or air.
• Thermal: Hot or cold fluids.
• Chemical: Hazardous chemicals like chlorine or fluoride under pressure.
• Gravity/Stored: An elevated gate valve or a compressed spring.

Authorized vs. Affected Employees

OSHA distinguishes between two main types of employees regarding LOTO:

1. Authorized Employee: A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on that machine or equipment. This is the person doing the work and applying the locks. They must receive detailed training on the energy control procedures for specific equipment.
2. Affected Employee: An employee whose job requires them to operate or use a machine or equipment on which servicing or maintenance is being performed under lockout or tagout, or whose job requires them to work in an area in which such servicing or maintenance is being performed. Affected employees must be notified before LOTO begins and after it is removed, but they do not perform the LOTO themselves.

Energy Isolation Devices

An energy isolation device is a mechanical device that physically prevents the transmission or release of energy.

• Examples: A manually operated electrical circuit breaker, a disconnect switch, a manually operated valve (like a gate or ball valve), a slip blind, or a line valve.
• Non-Examples: Push buttons, selector switches, and other control circuit type devices are not energy isolating devices. You cannot simply press "stop" on a pump control panel; the main breaker must be locked out.

The Lockout/Tagout Procedure

A comprehensive LOTO procedure involves several distinct steps that must be followed sequentially.

1. Preparation for Shutdown: The authorized employee must investigate and understand the type and magnitude of the energy, the hazards of the energy to be controlled, and the method or means to control the energy.
2. Equipment Shutdown: The machine or equipment must be turned off or shut down using established procedures. An orderly shutdown avoids any additional or increased hazard to employees.
3. Equipment Isolation: All energy isolating devices that are needed to control the energy to the machine or equipment must be physically located and operated in such a manner as to isolate the machine or equipment from the energy source(s).
4. Application of LOTO Devices: Authorized employees must affix lockout or tagout devices to each energy isolating device.
   • Lockout devices must hold the energy isolating devices in a "safe" or "off" position.
   • Tagout devices must indicate that the operation or movement of energy isolating devices from the "safe" or "off" position is prohibited.
5. Control of Stored Energy: Following the application of lockout or tagout devices, all potentially hazardous stored or residual energy must be relieved, disconnected, restrained, and otherwise rendered safe. This might involve bleeding down pressure in a line, draining a pipe, or blocking an elevated gate.
6. Verification of Isolation: This is the most critical step. Before starting work on machines or equipment that have been locked out or tagged out, the authorized employee must verify that isolation and de-energization of the machine or equipment have been accomplished. Test, don't guess. Attempt to start the equipment using normal controls, or use a voltmeter to confirm zero electrical voltage. After testing, return operating controls to neutral or "off."

Removal of Lockout/Tagout

The process of removing LOTO devices and restoring energy is just as dangerous as applying them and must follow specific steps.

1. Inspect the Work Area: Ensure that nonessential items (tools, spare parts) have been removed and that machine or equipment components are operationally intact.
2. Notify Affected Employees: Inform all affected employees that the LOTO devices are being removed.
3. Check for Employees: Ensure all employees are safely positioned or removed from the equipment area.
4. Remove Devices: Each lockout or tagout device must be removed from each energy isolating device by the employee who applied the device.
5. Restore Energy: Safely restore energy to the equipment.

The "One Lock, One Key, One Person" Rule: The fundamental rule of LOTO is that a lock must only be removed by the person who put it there. This ensures that a worker's lock cannot be removed while they are still working on the equipment. If the person who applied the lock is unavailable (e.g., they went home sick), strict, documented management procedures must be followed to verify their safety before removing the lock.