Exceptions to LOTO

12/16/2019

Workers that perform maintenance as well as repairs on machinery and/or heavy equipment should be quite familiar with OSHA’s lockout/tagout regulation; technically titled, The Control of Hazardous Energy.  This regulation is published under OSHA’s general industry standard, 29 CFR 1910.147 and addresses the safety of employees engaged in servicing and maintenance activities in general industry where an exposure to the unexpected release of hazardous energy exists. The standard incorporates performance requirements which allow employers flexibility in developing lockout-tagout programs suitable for their operations.

While lockout/tagout, or LOTO, is designed for worker safety by ensuring machinery will not unexpectedly start while an employee is working on, or inside a piece of equipment, there are particular circumstances where LOTO is not required.

First off, it is important to briefly explain the basic requirements of the LOTO process. Whether a piece of equipment is electrical or pneumatic or energized by gasoline/diesel, the power needs to be disconnected and then physically controlled from operating by placing a lock on the energy source.  Then – to ensure any residual or stored energy has been released – the equipment is turned on at the point of operation. This ensures workers will not get hurt from accidental mechanical movement. Next a tag is placed on the point of power input; thus, ensuring that an unsuspecting worker understands that the equipment has been turned off purposely and therefore, the lock should not be removed. LOTO also requires that those that operate the equipment (aka: affected employee) and those that will be performing work (aka: authorized employees) maintain keys to remove the locks once the work is completed.  They are the only persons to remove locks.

Unplugging the equipment must address all energy sources. Several pieces of equipment still pose a hazard even after the electrical power source has been cut off or unplugged due to residual energy. For example, unplugging a compressor does not eliminate the residual pneumatic energy in storage tanks, cylinders and transmission lines. And electrical equipment with capacitors may still hold an electrical charge even though the plug has been disconnected from the outlet.

While LOTO is necessary to protect workers, there are times when LOTO may not be appropriate. And OSHA has defined eight criteria that must be met for a piece of equipment to be exempt from requiring a documented energy controlled LOTO procedure (29 CFR 1910.147(c)(4)(i). All eight criteria (below) must be met. Failure to meet even one will result in the equipment needing a documented machine-specific energy control procedure. The criteria are: 

1. There can be no potential for stored or residual energy or re-accumulation of stored energy after shutdown;
2. The machine or equipment must have one single energy source which can be readily identified and isolated;
3. The machine/equipment must be completely deactivated by the isolation and locking out of the identified single energy source;
4. The machine or equipment is isolated from that energy source and locked out during servicing or maintenance;
5. The machine or equipment must be controlled and locked out by use of a single lockout device; 
6. The lockout device is under the exclusive control of the authorized employee performing the servicing or maintenance;
7. The servicing or maintenance does not create hazards for other employees; and
8. There have been no accidents involving the unexpected activation or re-energization of the machine or equipment during servicing or maintenance.

One of the most commonly misunderstood exemptions is the cord and plug exception. LOTO procedures do not have to be implemented when servicing or maintaining cord-and-plug connected electrical equipment IF complete de-energization of the equipment is achieved by unplugging the power cord from its energy source; and the plug is kept under the exclusive control of the worker performing the service and/or maintenance activity. “Exclusive” means if two or more employees are working on one piece of equipment, this exception is not applicable. “Control” means the plug must constantly remain in the possession of the worker performing the work – holding the plug, sticking the plug in their pocket – or in arm’s reach while being in the line-of-sight of that worker. If that is not possible, then the plug must be secured with a lockout-tagout device.

Hot tap is a procedure used in the repair, maintenance and services activities which involves welding on a piece of equipment (pipelines, vessels or tanks) under pressure, in order to install connections or appurtenances. It is commonly used to replace or add sections of pipeline without the interruption of service for air, gas, water, steam, and petrochemical distribution systems. Hot tap operations are exempted from the LOTO standard if the employer can demonstrate that:

• Continuity of service is essential;
• Shutdown of the system is impractical;
• Documented procedures are followed; and
• Special equipment is used which provides effective employee protection.

Below are some examples of equipment/machines that are commonly thought to fall under this exemption – but, however, do not:

• Exhaust fans have electrical and residual moving parts energy sources.
• Trash compactors have electrical energy and stored hydraulic and pneumatic energy sources.
• Overhead doors have electrical, pneumatic and hydraulic energy sources.
• Mills, lathes and drills all have electrical and kinetic energy sources and possibly hydraulic or pneumatic sources.

Exceptions to the LOTO standard can help employers optimize the operation and maintenance of equipment by reducing the time it takes for the tasks to be completed. However, employers must ensure that when such exemptions are used, worker safety must always be the priority, thus requiring the employer to implement specific control approaches. 

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