Deep Insight of LOTO (Lockout&Tagout) Part 3

So specifically, how do you implement LOTO? Some companies have eight steps, others nine or even ten. For industries with more machinery and equipment, I prefer nine steps.

The first step is to prepare the equipment before shutting it down.

Don't underestimate this step, it involves a lot of things. An important step is to communicate with those who may be affected. Why this step is important, you can watch the video below.

Procedure of lockout and tagout, step one, preparation of shutdown equipment. For some companies, production is an assembly line and equipment is not separated from other equipment. If only equipment to be cleaned or repaired is energy isolated without notifying upstream equipment operators, material from upstream equipment may be transferred to equipment that needs to be repaired or cleaned. Then the personnel working on the equipment may be in danger.

For some companies, production is an assembly line and equipment is not separated from other equipment. If only equipment to be cleaned or repaired is energy isolated without notifying upstream equipment operators, material from upstream equipment may be transferred to equipment that needs to be repaired or cleaned. Then the personnel working on the equipment may be in danger (as shown below). In this case, energy isolation of upstream devices is also required. Therefore, the judgment and communication of this affected person is very important. This includes downstream equipment. If the equipment you are working on has material going to the downstream equipment, communicate with the affected personnel downstream as well. For example, when a tank containing chemicals is cleaned, the downstream pipeline does not receive chemicals. Some operators forget to close the discharge valve of the downstream pipeline when the operation is completed. When the tank is finished feeding, the downstream pipeline is also filled with chemicals, and the discharge valve is left open, which can cause a chemical leak.

Of course, in addition to notifying the affected personnel, there are some other preparatory work, such as preparing the necessary tools, locks and so on, cleaning up the work site and so on.

Step two: Turn off the device.

Shutting down equipment here does not mean isolating energy. It simply refers to the shutdown of a device, that is, to stop a running device. Now many advanced devices do not have buttons, is the operation panel on the start and stop. After the electrical disconnector is turned off, the device start button in the operation screen will also show that the device is off. After the disconnector is turned on again, the device will not start directly. You need to press the start button again to start the device. Some old equipment has a button. If it is not closed, the energy is isolated without turning the switch to the off state. Then when it is re-closed or connected to the energy, the equipment may be directly started, which may be dangerous. For example, some simple stirring equipment or hand tools in the laboratory. In addition, some equipment has a heating device, such as heat conduction oil heating device, can not be directly shut down, need to cool to a certain degree to shut down, otherwise it will cause equipment loss. Therefore, the second step to close the device should be shut down in accordance with the correct device shutdown process, not directly pull the power supply or press the emergency stop.

Step three: Isolate the energy. 

Find the power isolator and shut it down. Many companies will develop LOTO SOP or operating instructions for each device to identify potential hazardous energy sources and energy isolation points, and even display the specific location of the isolation points in a visual way for operators to find. The quarantine points should also be labeled to make it easier for employees to find them and reduce the risk of mistakes. For example, the label number on the disconnector of each motor matches the motor number. It should be noted that, in principle, emergency stop device, button switch and so on cannot be used as energy isolation device. Generally, the isolation switch is a switch with visible breakpoint, which can physically isolate energy.

Step 4: Lockout&Tagout.

 Lock and sign the energy isolation unit. Now many power supply disconnectors have a lock hole, you can directly lock with a lock. But there are a lot of energy isolation devices, such as compressed air ball valve switch, gate valve switch is not a lock hole can be locked, which requires the help of some locks, the switch is fixed, and locked. There are a lot of specific locks on the web, Beidi, Master and many other introductions, you can find on the web, here is not much to repeat. When locking, remember to attach the tag and fill in the contact information, so that if the locking time is long and other departments urgently need to resume use, they can contact to unlock, to avoid the risk caused by forced unlocking in unknown circumstances. It should be mentioned here that the key must be taken with the operator after locking, and cannot be handed to others or placed in the isolation point. The so-called own life to control yourself. Check out this video:

The fifth step is to release or control residual energy. 

For some operations, the isolation of hazardous energy alone will not eliminate the risk completely, and the equipment may have residual hazardous energy, such as high temperature, pipe pressure, or hazardous chemicals in the pipe. If cleaning or maintenance operations may come into contact with these residual hazardous energy sources without prior release or control, hazards may arise during the operation. For example, when a pipe is being removed, chemicals or pressurized materials can spew out and injure people. Another example is that when a hydraulic device is in a high place, the hydraulic pipe breaks, and the device falls down, crushing the personnel working below. The following video might make that a little bit easier to understand.

Step six: Verify the effectiveness of energy isolation. 

This is the most important step, and one that many people miss. Sometimes the work site is more complex, there are many isolation points, and the mind also has dizzy, at this time if the wrong isolation switch is locked, it is also possible. If the wrong switch is locked and someone else accidentally activates the device, the operator could be in danger. Therefore, before the formal assignment, be sure to verify that the lock is correct. The most common way is to press the device start button again to see if you can start the device. In the case of pipelines, some can be determined by opening the drain bottom valve to see if there is still material outflow, to determine whether the isolation of the pipeline is complete. Of course, pipeline isolation in the chemical industry is often more complex, requiring blind cutting, and even double isolation emptying, etc., which is not introduced in detail here. The following video shows the importance of verifying isolation. Here, it should be reminded that for some simple switch control equipment, remember to switch to the off state after verification, to prevent the equipment from resuming to start and turning on the power, the sudden start of the equipment is dangerous, such as some stirring equipment.

The seventh step is starting to do task.

Step eight: Restore equipment protection. 

Some operations require the removal of equipment shields or protective devices. After the completion of the operation, the appropriate protective devices must be restored before the equipment can be restarted. In addition, you need to clean up the tools in the workplace. Do not leave the tools in the equipment. Otherwise, the equipment may be dangerous or damaged. For example, maintenance personnel leave a wrench in the equipment. When the rotating part of the equipment is opened, the wrench may be thrown out and hurt people around. Here, also need to count the number of people, many large equipment may have a lot of people involved in the operation, missing one or two people may not be easy to detect. For example, a large reactor operation, if someone does not come out before starting the equipment, it will be a big accident. So why do you require every worker to have a lock? If someone's not out, then the device can't be opened.

Step nine, release the lock. 

When unlocking, be careful not to let someone else pick the lock for you if you haven't finished the job. Why? You can watch the video below.