Lockout/tagout is a lifesaving safety practice for electricians. There are also lockouts that recognize mechanical power, which is important for electricians to know as it broadens the concept of LOTO safety on the job site.

Hazardous energy is the thing to avoid electrically and mechanically. Electrically, sometimes complete de-energization may not be the best option or possible in various circumstances. So, there are alternative actions, which are covered in the American National Standards Institute’s and the American Society of Safety Professionals ANSI/ASSE Z244.1-2016 (R2020)—The Control of Hazardous Energy Lockout, Tagout, and Alternative Methods. The standard speaks to hazardous energy and its unexpected startup or release of stored energy. (The American Society of Safety Engineers became the American Society of Safety Professionals in June 2018.)

Z244.1 establishes guidelines to control what it describes as “hazardous energy associated with machinery, equipment, or processes that could do harm to personnel.” OSHA addresses hazardous energy release related to machinery and equipment in “The Control of Hazardous Energy (Lockout/Tagout)” (29 CFR 1910.147). Both standards complement each other as they identify measures for controlling hazardous energy from electrical, mechanical, hydraulic, pneumatic, chemical, thermal and other energy sources.

Within a manufacturing space, machinery can pose a particular risk if LOTO is not correctly followed. OSHA finds that the failure to control hazardous energy represents as much as 10% of serious accidents across industries. 

There are many activities where hazardous energy can become a problem, including the installation and needed repair of machines and other equipment. In particular, clothing getting caught in machinery has led to a number of injuries. And so, a different approach to LOTO reserved in large part for machinery exists, as OSHA states, “to protect workers from the unexpected startup of equipment or release of hazardous energy.”

Understanding Z244.1

ANSI/ASSE Z244.1 was initially developed in 1989. The most recent updates to the standard were made in 2016 and reaffirmed in 2020. A 2024 edition is expected this year. Bruce Main is president of Ann Arbor, Mich.- based Design Safety Engineering Inc., a consulting firm specializing in better safety through risk assessment, hazard identification, better design and software. He also serves as the chair of the ANSI/ASSE Z244.1 committee.

“De-energizing a whole building when working is not always feasible, especially for an extended time,” Main said. “You may be affecting other contractors who need to do their work. You might be taking down an entire community’s power. I think the Z244.1 standard offers solutions.”

ANSI’s description of Z244.1 defines the need for a workable hazardous energy control program that includes “identifying (assigning responsibilities, identifying tasks), operational procedures (documented procedures, for hazardous energy control, provisions for hazardous energy control interruption), implementation (selecting protective materials, communication and training), and program maintenance (monitoring/measuring, auditing of program elements).”

The standard establishes LOTO and alternative methods to control hazardous energy for several activities related to machines, equipment or processes. Such activities could include installing, constructing, repairing, adjusting, inspecting, unjamming, setting up, testing, troubleshooting, cleaning, dismantling, servicing and maintenance. 

It also describes examples of unexpected startups or releases of energy. For example, stored energy from a steam valve could burn workers repairing a downstream connection. A jammed conveyor system, if suddenly released, could crush a worker. Other potential injuries including electrocution, burns, cuts and lacerations, amputation or bodily fractures.

Alan Metelsky, who also serves on the ANSI Z244.1 committee and is chief controls engineer for Design Safety Engineering, recognizes that while the National Electrical Code safeguards working on live electrical systems, LOTO of electrical alone to avoid energization misses mechanical equipment concerns.

“Helping to prevent the unexpected startup of equipment is different than energization,” Metelsky said. “Procedures for equipment lockout and electrical lockout are different. Equipment lockout may immobilize (e.g., a spinning blade), but making sure that all the electricity is isolated and removed may be missed. That is something I think electricians must factor in and recognize.”

He emphasized the importance of testing by electricians to make sure de-energization is achieved for equipment. That includes “test out” procedures, known popularly as the “tryout step.” 

He described it this way: “Many times, pieces of equipment will have a lockout procedure wherein testing will say ‘attempt to restart the equipment.’ It may not restart. There could be several reasons, but it may not be electrically dead. That is the big point for electricians to remember. Written procedures when doing electrical work may not consider mechanical lockout.”

Main added an example of a tryout step. “The test method for electrical work tends to be an electrical test, whereas the test method for motion tends to be try the equipment out, see if you can start it. And so, if I am going to try to change a motor and I am going to unwire the connections when I do my lockouts, my tryout step should include electrical testing to make sure the motor is dead. The lockout/tagout process then becomes different, depending on the work you are doing,” he said.

ANSI/ASSE Z244.1 is telling the electrician and other workers never to assume anything.

“That’s a fair bet as an electrician,” Metelsky said. “If you care about motorized equipment being electrically dead, you want to make sure that you have done your testing to ensure it is adequately locked out. It could have residual energy. A disconnect for a certain motor could also be mislabeled or it was miswired, resulting in accidents. That is why the tryout step is so important.”

Mechanical cousin to LOTO

Alternative methods for machine operator LOTO can be helpful for electricians.

“Remember, alternative methods are a way of controlling energy, not isolating it,” Main said. “This approach may be helpful for electricians when traditional electrical lockout/tagout [is] not feasible or practical.”

“There’s a lot of very new technologies out there that allow us to place equipment in a safe state, often related to motion” he said. “For example, an electrical motor is a common, modern feature of variable frequency drive. Something called ‘safe torque-off’ is now readily available on electrical drives. A control circuit can render that drive so the motor doesn’t move. This feature might use an interlock gate or another type of control system to prevent the machine from moving. The power to the drive is still on, but the operator is using an alternative method to control the hazardous energy by stopping the equipment from moving.”

For electricians, hazardous energy primarily takes the form of electrical energy. Shock hazards and arc flash hazards are top of mind, depending on the project.

“That is how hazardous and electrical energy tends to manifest,” Main said. “Other hazardous energy resulting from mechanical motion powered by an electrical motor or the use of pneumatics (compressed air), are another concern. If you are isolating the energy in the electrical sense, the equipment is dead, and you cannot get hurt. If you are controlling the energy on a mechanical system to avoid injury, you are using a control system in most cases. That is the difference.”

Gravity and more

As an aside, gravity is listed as a hazardous energy. 

“If you are working on a palletizer and it is in the raised position, you must go underneath the palletizer,” Main said. “As you know, the palletizer might fall because of gravity. Danger in this case is not from a mechanized piece of equipment unexpectedly starting. The standard is written to address both circumstances.”

The standard also identifies other hazardous energy, such as water pressure and chemical energy. And while electricians might not be exposed directly to these dangers, they may relate to their jobs on-site. Awareness provides for a safer workplace.

“Say you are going into a robot cell,” Metelsky said. “This presents a larger impact to electricians, electrical technicians and control technicians. Alternative methods place demands on electricians to wire these systems correctly, to troubleshoot them correctly and to repair them correctly so that they continue to be safe. By doing their job, they are helping make the jobs of other technicians safer.”

Finally, in comparing the two standards (ANSI/ASSP and OSHA), Main explained how Z244.1 continues to evolve. People can use guidance in methodologies to take advantage of current technology and systems. For its part, Main added that OSHA is working on a revision to their rules.

“[Metelsky] and I have flown to Washington several times to work with OSHA, so they understand the ins and outs of current technology and how it assists in lockout. Z244.1 and OSHA’s 1910.147 represent two different systems,” he said.

Metelsky added that the requirements for LOTO between the two standards are actually very close, but Z244.1 provides a lot of additional guidance and information beyond 1910.147. The 2024 edition will help further simplify and clarify alternative methods.

Main added organizations such as the National Institute for Occupational Safety and Health and the National Fire Protection Association are looking for accident prevention through new and better equipment design where safety is built in, helping electricians and operators.

“We can design systems that enable safer operation and processes if we can get engaged earlier, helping designers better understand the work that needs to be done,” he said.

LOTO might mean something different to an electrician and an operator, but safety means the same thing. The better each understands the other’s approach to LOTO, the better both could help the other in maintaining a safe work site.  

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