Hot Topics: Lockout/Tagout and Machine Guarding

Hazard of Unexpected Energization

The Lockout/Tagout standard does not apply to servicing and maintenance operations if employees are not exposed to the risk of injury from the unexpected energization, start up, or release of hazardous energy while performing service or maintenance tasks.

Some servicing or maintenance activities do not expose workers to potential harm from the unexpected energization, startup, or release of hazardous energy because precautions taken by the employer provide effective employee protection when performing servicing and maintenance operations. These measures may include the use of a multi-step startup procedure, time delays, or audible warnings. In such relatively uncommon situations, lockout/tagout requirements do not apply. However, such alternative precautions must be carefully evaluated for their effectiveness in light of the configuration of the machinery, the reliability of the alternative measures, employee training, and other factors.

The Lockout/Tagout standard does not apply to servicing or maintaining cord- and plug-connected electrical equipment when the equipment is unplugged from its energy source and the plug is under the exclusive control of the employee performing the service and/or maintenance activity. "Under the exclusive control" refers to instances in which the plug is physically in the possession of the employee, or in arm's reach and in the line of sight of the employee, or in which the employee has affixed a lockout/tagout device to the plug. This enables the employee to prevent the equipment from becoming reenergized during servicing or maintenance.

Normal Production Operations vs. Servicing and/or Maintenance

The Lockout/Tagout standard makes a distinction between two types of workplace activities: servicing and/or maintenance and normal production operations. It is intended to provide employees with protection from the unexpected energization, start up, or release of stored energy, while performing servicing and/or maintenance operations. The machine guarding standards are intended to provide employee protection against the hazardous energy associated with normal production operations. However, certain types of servicing and/or maintenance performed during normal production operations are also subject to the Lockout/Tagout standard.

Under the Lockout/Tagout standard, normal production operations are defined as the utilization of a machine or equipment to perform its intended production function.

Normal production operation is the mode in which an energized machine or equipment operates to either manufacture a product or perform a function necessary to assist in the manufacturing process. This mode of operation may present additional hazards to employees, including points of operation; e.g. ingoing nip points, crushing hazards due to the motion of the machine or equipment and due to the movement of the power transmission apparatus. The machine guarding standards establish provisions for employee protection against hazardous energy and points of operation while the equipment is energized in order to perform its intended production function.

Employee protection from hazardous energy during normal production operations is generally accomplished by compliance with applicable machine guarding standards. However, if a servicing or maintenance operation takes place during normal production operations, and the employee is required to remove or bypass machine guarding required by Subpart O, or to place part of his/her body into an area in which he/she is exposed to the unexpected energization or activation of the equipment, the protections of the Lockout/Tagout standard would apply. In these circumstances, the employee performing servicing or maintenance would be subjected to hazards that are not encountered as part of the normal production operation.

Servicing and/or maintenance is defined as workplace activities, including installing, setting up, inspecting, adjusting, repairing, replacing, constructing, modifying, and maintaining and/or servicing machines or equipment. These activities include lubrication, cleaning or unjamming of machines or equipment, and making adjustments or tool changes, during which the employee may be exposed to the unexpected energization or startup of the equipment or release of hazardous energy. Setting up would include any work performed to prepare a machine or equipment to perform its normal production operation.

Many servicing and/or maintenance activities require the machine, equipment, or its components to be disassembled or dismantled. These tasks are typically performed with the equipment stopped. Other servicing and maintenance activities would not require the employer to disassemble or dismantle the machine or equipment but would nonetheless require shutdown of the equipment or machine. This would cause the associated production process to be discontinued during the servicing and maintenance.

Servicing and/or maintenance activities may expose an employee to the unexpected energization, start up, or release of stored energy. The Lockout/Tagout standard establishes provisions to deenergize equipment in such cases and to render all potentially hazardous energy safe, prior to engaging in servicing and maintenance activities. These provisions are intended to protect employees from the equipment being energized or started while servicing and/or maintenance is being performed.

Minor Servicing Exception

Some servicing operations performed during normal production operations are excepted from coverage under the Lockout/Tagout standard. This exception is referred to as the minor servicing exception. The Lockout/Tagout standard is not intended to cover minor servicing activities that are necessary to carry out the production process provided that associated danger zones are properly guarded. The machine guarding standards cover these types of operations.

The Lockout/Tagout standard contains specific criteria that must be met for the minor servicing exception to apply. Minor tool changes and adjustments,and other minor servicing activities that take place during normal production operations, are not covered by the standard if they are routine, repetitive, and integral to the use of the equipment for production, provided that the work is performed using alternative measures which provide effective protection.
If the servicing operation is routine, repetitive, and must be performed as part of the production process, the employer must use alternative protective methods or safeguarding devices (such as remote oilers and specially designed servicing tools), to protect employees.

Three specific criteria can be used to determine if the minor servicing exception would apply to a particular activity.
First, the activity must be conducted during normal production operations, i.e., while the machine or equipment is actually performing its intended production function.
Second, the activity must be:
  • Routine: The activity must be a regular course of procedure and be in accordance with established practices.
  • Repetitive: The activity must be regularly repeated as part of the production process.
  • Integral: The activity must be essential to the production process.
Third, if all of these apply, the employer must use alternative measures to provide effective protection from the hazardous energy. Some acceptable alternative measures include specially designed tools, remote devices, interlocked barrier guards, local disconnects, or control switches which are under the exclusive control of the employer performing the minor servicing. These alternative measures must enable the employee to safely perform the servicing task without being exposed to the unexpected energization or activation of the equipment, or the release of stored energy.

If the minor servicing exception is not met in full, the Lockout/Tagout standard is applicable and the machine or equipment must be deenergized and all potentially hazardous energy rendered safe.

Examples of Servicing and Maintenance vs. Normal Production Operations and Minor Servicing

Printing Shop
In a printing shop, when a printing press is being used to produce printed materials, there is often the need to make minor adjustments such as to correct for paper misalignment while the press is running. This is a part of the production process, and is subject to the machine guarding requirements. The use of remote control devices which keep the employees from reaching beyond the machine guards, or the use of inch (or jog) devices that permit machine speed control for test purposesobviate the need for lockout/tagout. However, printing presses may jam, requiring an employee to bypass the machine guards in order to reach the area of the jam and clear it. Although the need to unjam the machine arises during normal production operations, it is a servicing activity that involves employee exposure to unexpected activation of the machine or release of energy, and is covered under the Lockout/Tagout standard.
Machine Shop
In a machine shop, a milling machine operator must adjust the flow of coolant oil to parts being milled while the cutting tool is in operation. This operation, which is part of the normal production process for the machine, is covered by the machine guarding requirements, which prevent employee contact with nip points and other points of operation. However, if it becomes necessary to perform an adjustment which requires the employee to bypass a guard or to place any part of his/her body in an area where work is performed on the material or where a danger zone exists during the machine's operating cycle, the Lockout/Tagout standard applies. If this step is performed without having to bypass the guard, reach into a danger zone, or otherwise expose the employee to the potential release of energy or the unexpected activation of the machine, the Lockout/Tagout standard would not apply.
Plastic Sheet Application Machine
An employee is operating a machine that applies and seals a clear plastic sheet around a packaged product. There is a blade on the machine that cuts the plastic sheets, and this blade must be cleaned periodically during the production process. Since the process must be stopped to clean off the blade, that this operation is more in the nature of servicing or maintenance than normal production; on the other hand, since it must be performed frequently during production, it is arguable also part of the production process. Because the requirements of the Lockout/Tagout standard and Subpart O dovetail, protection must be provided regardless of whether the above operation is considered to be production or servicing. If it is considered by the employer to be production, the employee must be fully protected from the dangers of contacting the blade or other harmful machine parts; the cleaning must be done with special tools and procedures to provide the necessary protection. However, if it is considered to be servicing, outside of production, and the employee is exposed to a point of operation or an associated danger zone, the provisions of the Lockout/Tagout standard would apply.


john said...

Lockout tagout training programs can definitely help workers performing service or maintenance on machinery and equipment who are exposed to injuries from the unexpected energization, startup of the machinery or equipment, or release of stored energy in the equipment. With this education the workers will be able to know how to properly service and operate machinery without risking their safety.

Anonymous said...

You might wonder why you would have to install guards on your woodworking or metal working machines. Aren't manufacturers required to install guards on the machines they sell? The short answer to that is no. Many manufacturers continue to build and sell their tools without the necessary safeguards and electrical controls required by OSHA and various safety regulations. Machine Guarding is used for ensuring employee safety and stopping projectiles.

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