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Course 710 - Energy Control Program (Lockout/Tagout)

Safety guides and audits to make your job as a safety professional easier

Application of Energy Control Devices

Basic Steps in Controlling Energy

LOTO follows an equipment-specific procedure.

To safely apply energy controls to machines or equipment (using either lockout or tagout devices), authorized workers must perform lockout/tagout procedures in the following specific order:

  1. notify all affected employees of the requirement for lockout/tagout;
  2. identify all energy sources;
  3. de-energize equipment by isolating or blocking the energy sources;
  4. dissipate the potential (stored) energy that could affect the equipment (such as capacitors);
  5. lock out the equipment's energy-isolating devices (switches, valves, etc); and/or
  6. tag out the equipment's energy-isolating devices if you can't lock them out.

To safely apply energy controls to machines or equipment (using either lockout or tagout devices), authorized workers must perform lockout/tagout procedures in a specific order.

1. After isolating or blocking equipment energy sources during lockout/tagout, what is the next step in controlling hazardous energy?

a. Tag out energy-isolation devices that can't be locked out
b. Lock out the energy-isolation devices (switches, valves, etc.)
c. Dissipate potential (stored) energy such as capacitors
d. Isolate or block energy sources to de-energize the equipment

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Preparing for Shutdown

The first step - identify equipment.

The first step in controlling energy is to identify equipment in your workplace that needs service or maintenance. Once the equipment or machinery has been identified:

  • determine the form of energy that powers the equipment, including potential energy that may remain when the energy source is disconnected; and
  • label the energy sources so that workers will know what equipment is powered by each energy source.

Before an authorized or affected employee turns off a machine or equipment, the authorized employee must have knowledge of:

  • 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. What is the next step after equipment has been identified for shutdown?

a. Determine the form of energy powering the equipment
b. Energize equipment after warning employees
c. Label all energy sources and affix tags
d. Dissipate kinetic and potential energy

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Shutting Down Machinery or Equipment

Isolate and De-energize equipment.

The machine or equipment must be turned off or shut down using the procedures established for it to avoid any additional or increased hazards to workers as a result of the unexpected machine or equipment startup or stoppage.

Isolating Machinery or Equipment

Energy-isolating devices that are needed to control the machine's energy source must be identified. These devices must then be used to isolate the machine or equipment from its energy source(s).

De-energizing equipment means isolating it from its energy source and controlling potential energy so that no energy can flow to the equipment. The method you use to de-energize equipment depends on the form of energy and the means available to control it.

This is a method to isolate piping systems.

Below is a list of safe practices for de-energizing equipment.

  • Disconnecting motors from the equipment
  • Isolating electrical circuits
  • Disconnecting equipment from energy sources
  • Blocking the fluid flow in hydraulic, pneumatic, or steam systems with control valves or by capping or blanking the lines
  • Blocking equipment parts that could be moved by gravity

3. During shutdown, what must be identified and used to isolate the equipment or machine from its energy source(s)?

a. LOTO devices
b. Energy-isolating devices
c. Electrical energy-isolating devices
d. Primary LOTO devices

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Dissipating Stored Energy

Isolating and de-energizing a transformer by grounding.

Stored energy must be released after equipment has been de-energized. Below is a list of possible sources of stored energy.

  • Capacitors
  • Coiled springs
  • Elevated machine members
  • Rotating fly wheels
  • Air, gas, steam, chemical, and water systems

If the energy could return to a hazardous level, make sure that it remains isolated from the equipment until all service work is finished. Below is a list of safe practices for dissipating potential energy.

  • Vent pressurized fluids until internal pressure levels reach atmospheric levels
  • Discharge capacitors by grounding them
  • Release or block tensioned springs
  • Ensure that all moving parts have stopped completely

4. Releasing the potential energy in capacitors can be accomplished by _____.

a. releasing pressure
b. grounding them
c. releasing tension
d. stopping the moving parts

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Energy-Isolation Devices

Isolating a valve by chaining.

Energy-isolating devices prevent energy from being transmitted from an energy source to equipment. Energy-isolating devices are the primary means for protecting those who service equipment. Examples of energy-isolation devices include:

  • manually operated electrical circuit breakers;
  • main disconnect switches;
  • line valves; and
  • blocks.

Control circuit devices

Control circuit devices such as start/stop push buttons, e-stops, selector switches, presence sensing devices, or limiting switches do not physically isolate equipment from the equipment's energy source. For this reason, OSHA 1910.147 explicitly rejects control circuitry in the definition of an energy-isolating device.

However, under the "minor servicing" exception provided in 1910.147(a) (2)(ii), circuitry meeting the control reliability requirements of ANSI B11, Machinery Safety Standards, provides the alternative safeguarding measures required under the exception.

Applying Lockout/Tagout Devices

Locking out. Locking out is a procedure for securing an energy-isolating device in an off, closed, or neutral position. When an energy-isolating device is locked out, a worker can safely service hazardous equipment. A lockout device - typically a lock with a unique key or combination - secures the energy-isolating device in a safe position. When an energy-isolating device is locked out, the equipment it controls will not work until the lockout device is removed.

Tagging out. Tagging out is a procedure for placing a warning tag or sign - a tagout device - on an energy-isolating device. Remember, tagout devices must control hazardous energy at least as effectively as lockout devices.

Bottom line: If you can lock it out, do not use tags.

5. Lockout devices must secure energy-isolating devices _____.

a. in the off, closed, or neutral position
b. using tags with a plastic tie
c. with insulating disconnect switches
d. by opening circuit breakers

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Key Criteria When Applying Lockout/Tagout Devices

Lockout devices must meet specific criteria.
  • Lockout or tagout devices must be attached to each energy-isolating device by authorized workers.
  • Lockout devices, where used, must be attached in a manner that will hold the energy isolating devices in a "safe" or "off" position.
  • Where tagout devices are used, it must be attached in a manner that will clearly indicate that the operation or movement of energy isolating devices from the "safe" or "off" position is prohibited.
  • If the tag can not be attached directly to the energy isolating device, the tag must be located as close as safely possible to the device, in a position that will be immediately obvious to anyone attempting to operate the device.
  • A tagout device must be securely fastened to the energy-isolating device and must state that the equipment being serviced can't be operated until it is removed.
  • The tags must be attached where the lockout devices would be located.
  • You must demonstrate (prove) that the tagout system will provide protection at least as effective as locks and will assure full employee protection.

6. What should be done if a worker cannot lockout an energy-isolating device?

a. Place a guard around it
b. Tag it out
c. Post a warning sign
d. Place tape over it

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Lockout, Tagout, or Lockout/Tagout? How to Decide

You have three choices when isolating energy sources:

  1. Lockout (LO). If you can lock out an energy-isolating device, then you must lock it out before you service the equipment that it controls.
  2. Tagout (TO). If you can't lock out an energy-isolating device, then you must tag it out.
  3. Lockout/Tagout (LOTO). A best practice is to use both locks and tags. Require authorized employees to attach a tag when securing the lockout device. Provide custom tags that include pictures of authorized employees.

Full Employee Protection

Can a tag provide the same level of protection as a lock?

You must demonstrate the protection achieved using the tagout program is equivalent to the level of safety obtained by using a lockout program.

So, how do you do it? You must comply with all tagout-related provisions and use additional safety measures that provide a level of safety equivalent to that obtained by using lockout.

Examples include:

  • removing and isolating a circuit element;
  • blocking a controlling switch;
  • opening an extra disconnecting device; and
  • removing a valve handle to reduce the potential for any inadvertent energization while the tags are attached.

7. If you use tagout devices, you must prove they _____.

a. prevent inadvertent exposure to equipment isolation
b. successfully protect employees
c. provide safety equivalent to lockout devices
d. will provide a minimum level of employee protection

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Verifying Machinery or Equipment Isolation

Verifying equipment is shut down.

Each authorized employee must place his or her personal lock on each energy-isolating device before beginning service work. Service work involving many workers and many energy-isolating devices can make traditional lockout complicated.

Before any work begins on machines or equipment that have been locked out or tagged out, an authorized employee must verify that the machine or equipment has been properly isolated and de-energized. To do that, the authorized employee will attempt to turn the equipment or machinery on by cycling the energy isolation devices.

Attempting to restart the equipment is one way to confirm isolation; however, the authorized person should also test, as necessary, all components ensure they have been properly discharged, hazardous heat has dissipated, and excessive pressures have been relieved (zero-energy states).

Best Practice: Some companies refer to their energy control program as "Lock, Tag, Try" or "Lock, Tag, Test" to emphasize this important verification step.

8. To properly confirm isolation of equipment, what should the authorized employee do in addition to attempting to restart the equipment?

a. Identify the equipment to be isolated
b. Ensure proper documentation of LOTO steps
c. Get permission to begin servicing or maintenance
d. Test all components for zero-energy states

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Energy Control Devices

Watch this informative video produced by Brady on the application of various lockout/tagout devices.

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