Lock Out Tag Out: Protect Yourself from Hazards

LOTO for short

It is the process of identifying, securing, and tagging an energy source(s) on a piece of equipment. It's not the most exciting topic but it is crucial for ensuring a safe working environment when working on equipment. In a nutshell, you identify what potential sources of energy from various sources are in a particular piece of equipment. You then secure it, typically by turning a valve or flipping a switch and then putting a physical lock on it. If you have tags with holes, put the lock through the hole. The tag typically has the name of the person working on it, how to contact them, or whatever information your company deems necessary for the procedure.

The reason this is important is not only so you don't accidentally do something to hurt yourself. It's also so someone else doesn't accidentally hurt you by turning on the machine you're working on. In some places cutting off another person's lock can result in serious legal action such as manslaughter or attempted manslaughter.

Types of 'energy'

Energy is the most commonly used term for describing what you are stopping by securing a lock. People typically think of electricity when they think of energy. That is true, however, unless you're working on something simple like a ballast, it'll likely have additional energy sources. 

Steam is common in many industries. Examples include laundry mats, assembly lines, and food service equipment. Failing to identify and lock this out can result in a range of bad things, from burns for minor exposure to low-pressure steam and even loss of life from high-pressure steam.

Pneumatics and hydraulics. Many pieces of equipment that have moving parts will have either of these two energy sources or both that control a wide range of parts. A piston may be held in place by air pressure and if not discharged before working on it, it can lead to pinch points. Similarly, hydraulics are often used on heavy lifting equipment and can maintain a state of going against gravity through a series of valves until the pressure is relieved. If you haven't discharged these energy states and secured them, you can end up gravely injured.

Other liquids. Sometimes it's water pipes. In a chiller, for instance, you'll have water from the compressor side and from the condenser side that will need to be secured if opening up the machine. In a draft beer system, you'll have glycol running through the lines to ensure the beverages are kept cold whilst waiting to be poured from the tap. Any type of pressurized liquid can be a potential hazard if allowed to flow while working.

Potential kinetic energy is the last one I will touch up on here. This is things like springs under tension, loads under tension, or anything fighting against gravity. These can't all be locked out but must be de-energized to be safe while performing work. Procedures vary for what kind of energy and environment you're in. Always use your head, read the manual, or ask a more seasoned employee or safety person if you're ever unsure.

Staying Safe

Now that you're aware of most types of energy, you also need to be sure to discharge any potential energy. It's not always potential kinetic. As I touched on a bit earlier, many pneumatic and hydraulic systems store high-pressure loads even when disconnected. So how do you discharge these energy sources?

Hit the start button, reset button, stop button, and or emergency stop button. Never assume everything discharges properly just because a machine is off and the energy source is secured. It's also possible someone rewired or repiped a system to 'make it work' during crunch time and never made the machine right again. I've found it's always better to er on the side of caution. You only have one life. It only takes one careless mistake to lose it.

Additionally, there may be manual relief valves. Often a lever that you push or pull to discharge the pressures in the system. As always, when in doubt read the manual or ask for help.

Each of the various sources of energy will require its own lock. Even something simple looking like a tunnel dishwasher may have 5 or more locks. They may have multiple voltages, steam in and out as well as water itself. When working with a team, you often have to secure your own locks at each lockout point. They sell special hardware that allows many locks on a single point. 

Formal Procedures

I've worked at a fair number of plants and properties and discussed with many across the industry and have learned that there is no real standard. As long as a company complies with OSHA requirements the procedures may be very simple, or a pain in the ass. Some make complete sense and some were so poorly thought out, that everyone could lose their job over it.

A great simple example from a property with just under 100 in the maintenance department. The shop had locks and tags in a box that you would sign out the number of the lock(s) and the location/equipment you were working on. If someone saw a lock, they radio the shop and ask who had lock number 7. The head engineer would radio back with whoever's name was in the book. The information was simple to find and work flowed smoothly.

A counter-example of the opposite nature. This small plant I was at required a manager to test, verify, and sign off on every single thing being locked out before it was worked on and then reconfirm before removing. It sounds great on paper. In practice, there are no managers on some shifts. We had a contactor go out the effectively shut down the plant since it shut down the main sorting machine. It was at 3am or so on a Saturday morning. While I was the head mechanic, I didn't have a manager title at the time and couldn't work on it without risking losing my job. On the other hand, if I didn't fix this and we waited for a manager to come in on Monday, the company might lose enough money for them to start layoffs. Needless to say, the plant manager and the onsite safety manager send out some emergency emails. They had my back as I did the work and I got a slap on the wrist from my boss for his mistake of not hiring more managers. A week later the LOTO procedure did end up changing for the company worldwide though. So some good did come out of it.

Ending notes

I'm sure there's plenty more to talk about this topic. It's not the most sexy or exciting but it is needed nonetheless. The last thing you want is for someone to turn on a machine you're inside and injure or kill you after all. Use your head, read the manuals, and double-check everything. I'm sure I will add more to this page especially along with other safety-related topics on this site.