For those not familiar with this acronym, LOTO refers to lockout/tag out, the process by which equipment is put into a safe condition so repairs or maintenance can take place. As research laboratories become more automated and complex with sophisticated equipment such as automated pipetting systems, autoclaves, centrifuges, and ultralow-temperature freezers commonplace, facility managers must stay alert to their intrinsic dangers.
Although considered necessary only in large manufacturing and production plants, LOTO is needed whenever equipment needs servicing, which, as we know, includes laboratories. Lockout/ tag out measures are taken to prevent the release of unwanted or stored hazardous energy. Failure to follow good LOTO procedures can result in some of the most gruesome and often fatal accidents in the workplace. Keep reading to learn how you can design and implement a successful lockout/tag out program for your facility.
When thinking about why LOTO is important, one television commercial comes to mind. Remember the one where the handyman husband has just finished installing a new garbage disposal under the kitchen sink but dropped something into it? As he is trying to fish it out with his arm inserted up to the elbow, his wife enters the kitchen and reaches to turn on the light. Now, being a capable electrician and handyman at home, would you want to bet your arm that you are certain which switch to flip?
During the period 1982 to 1997, NIOSH (National Institute for Occupational Safety and Health) found that 82 percent of fatal incidents involving maintenance or repair to equipment resulted from a failure to completely isolate or dissipate the energy source.1 In addition, a short four-year period between 1992 and 1996 saw accidents involving being caught in machinery kill almost 750 workers, while another 5,000 workers lost limbs by amputation.2 Sadly, every one of these could have been easily prevented. By implementing a good lockout/tag out program you may be able to ensure that your facility does not experience an ugly accident or worse.
The premise of LOTO is simple and straightforward: Isolate, dissipate, or otherwise prevent unexpected start-up or energizing of equipment that could cause injury. However, detailed planning and intimate knowledge of the equipment are paramount. For example, say a centrifuge needs servicing. Before the maintenance employee can begin work he must make sure the equipment cannot be turned on, which he does by tripping the circuit breaker and then placing a lock on the switch so someone else does not energize the unit while it is being serviced. It may be as simple as pulling the plug, but large equipment is usually hardwired, and it may not be this simple. In addition, there may be other dangers, such as stored energy.
Different types of hazardous energy
A good lockout/tag out program is exhaustive and meticulously detailed. Autoclaves, centrifuges, and other automated equipment are capable of injuring employees in numerous ways. This is because there are several forms of hazardous energy.
• Electrical energy is the most common yet still the cause of many injuries. Often overlooked are electrical storage devices such as batteries and capacitors.
• Thermal energy—either high temperature (e.g., steam) or low (e.g., liquid nitrogen)—is also easily recognized. Mechanical work, chemical reactions, electrical resistance, and radiation can also produce thermal energy.
• Potential energy is energy stored in pressure vessels (e.g., compressed gas cylinders), hydraulic and pneumatic systems, and mechanical devices (e.g., springs).
• Kinetic energy is associated with moving mechanical parts, usually resulting from release of potential energy.
Most automated equipment will contain more than one form of hazardous energy. Thus a thorough understanding of its operation and a detailed lockout/ tag out procedure are needed.
The OSHA standard for the control of hazardous energy, 29CFR1910.147, covers servicing and maintenance of machines and equipment where accidental start-up or release of stored energy can harm workers.3 It requires employers to establish a program and use procedures to lock out or tag out energy sources and to otherwise disable machines or equipment to prevent injury to employees. The first step is to develop a written program documenting the techniques and devices to be used, authorizing personnel, describing the training, and providing for program evaluation and compliance. Next, identify equipment in your facility that must follow LOTO and designate it with proper warning signs. Keep in mind that employers must provide needed lockout/tag out devices to trained and authorized personnel.
Lockout is placing a lock to hold an energy-isolating device in the safe position. Tag out is using a prominent warning device with a means of attachment, such as a tag, which can be securely fastened to an energy-isolating device. OSHA mandates that lockout take precedence over tag out. Tag out is allowed only where equipment is not capable of being locked out. Tags may evoke a false sense of security, and employees must understand their meaning. Tags are essentially warning devices affixed to energyisolating devices and do not provide the physical restraint that is provided by a lock.
The cardinal rule is “one lock, one key” to prevent inadvertent removal by another employee. Clearly label each lock with durable tags to identify the worker assigned to the lock. In general, the worker who installs a lock is the one who removes it after all work has been completed. The written program should have procedures on how to deal with maintenance or service that spans shift changes, special situations, and other absences.
The final check before beginning work is to verify that that all energy sources for the equipment are de-energized. For instance, the employee should try to start up the equipment and test that all forms of hazardous energy have been bled down, relieved, disconnected, restrained, and otherwise rendered safe.
After the maintenance or repair is complete, a reversal of the lockout/tag out procedures will ensure a safe start-up. Perform a final inspection to confirm that all tools and nonessential items have been removed and that the equipment components are properly installed. Make sure all affected employees are safely positioned and clear of potential danger zones. Finally, remove the lockout/tag out devices and notify affected employees of the removal and that start-up will commence.
A successful lockout/tag out program relies on good training. Regularly evaluate the program and check that proper procedures are being followed. Retrain employees whenever there are changes to job assignments or new equipment or energy control devices are installed. In addition, if you observe inadequacies in an employee’s knowledge or use of the energy control procedures, then retraining is necessary.
As always, the Safety Guys welcome your comments and questions. Until next time “Stay alert” and remember “Safety first!”
1. “Preventing Worker Deaths from Uncontrolled Release of Electrical, Mechanical, and Other Types of Hazardous Energy,” National Institute for Occupational Safety and Health, Center of Disease Control. Atlanta, GA. NIOSH publication 99-110, August 1999. http://www.cdc.gov/niosh/docs/99-110/
2. “Worker Fatalities from Being Caught in Machinery,” Windau, Janice A. Compensation and Working Conditions, Winter 1998: 35-38.
3. “The Control of Hazardous Energy,” Occupational Safety and Health Administration, US Department of Labor. Washington, D.C., 29CFR1910.147. May 2011. (http://www.osha.gov/pls/oshaweb/ owadisp.show_document?p_table=STANDARDS&p_id=9804 )
Vince McLeod is an industrial hygienist certified by the American Board of Industrial Hygiene and the senior industrial hygienist in the University of Florida’s Environmental Health and Safety Division. He has 22 years of occupational health and safety experience at the University of Florida, and he specializes in conducting exposure assessments and health-hazard evaluations for the university’s 2,200-plus research laboratories.
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