Lockout Tagout (LOTO)
Lockout Tagout (LOTO) is a set of procedures that should be followed to properly shut off machines and assure they are not able to be started up again until authorized persons allow it. It is a procedure for controlling hazardous energy sources from electrical, mechanical, hydraulic, pneumatic, chemical, thermal, or other sources in machines and equipment can be harmful to people.
In simple terms doing these things will save your life. The majority of accidents happen when standard operating procedures are not being followed such as maintenance, troubleshooting, and testing.
It is important that everyone person that is working on a machine follow their own lockout tagout procedure. Just because one person has followed the lockout tagout procedure doesn't mean that everyone is safe. The video to the right is a humorous but good example of the dangers of relying on someone elses lockout tagout to keep you safe.
Also for our instructors and students following this series of lessons with our PLC Trainers, do NOT think that you can skip this lesson until you are in the workforce. These are important skills that should be followed from the beginning. Plus for students using our more advanced trainers that include wiring exercises, these procedures just may keep your fellow student from accidentally plugging your trainer in instead of theirs and shocking you while your are wiring yours.
Lockout Tagout procedures are constantly improving so we recommend you check the latest safety standards such as Occupational Safety and Health Administration (OSHA) standard and the NFPA 70E which is specifically for electrical. OSHA CFR 1910.147 spells out the step by step requirement for lockout tagout. However, reading it can be intimidating. So below are the basic procedures for a basic machine. It is based off of NFPA 70E and only covers electrical so make sure you check and follow all applicable standards.
1. Communicate - Make sure everyone affected knows that you are preparing to lock the machine out, why, and for approximately how long. This one isn't in most procedures but may be the most important thing you can do in means of keeping yourself safe. It is especially important for contractors working in plants where they may not be familiar with all procedures.
2. Disconnect - Deenergize all sources of electricity from the equipment. Machines with multiple energy sources are supposed to be labeled as such but always be on the lookout for additional conduits that seem to leave the machine that could contain voltages from other sources.
3. Release or Contain Stored Energy - Many machines may have capacitors with special instructions or additional wait time needed before servicing equipment. Also machines can store up mechanical energy in the for of flywheels, pneumatics, and hydraulics that either must be bled off (release) or contained such as is the case when mechanical jacks have to be put in place to prevent mechanical movement.
4. Lockout and/or Tagout - In most cases you will apply a lock and a tag to the main disconnect of the machine. There are instances when you can't disconnect the power and can only tagout a machine. Those instances usually require additional procedures to be followed. Also another note for contractors, while most tags to not have a field for it, I have found it very helpful to include my cell number on the tag so personnel in the plant can contact me immediately. This has prevented dangerous situations more than once where plants had wrongly assumed I had left for the day and I had only ran out to grab some parts.
5. Checkout - This is the most missed step of a basic lockout tagout procedure. Check to make sure the energy is disconnected. Make sure the disconnect won't operate with the lockout in place. Also check that all lights and screens on the machines went out. It isn't uncommon for them to be powered from different sources. Also in addition to taking a volt meter such a this one and checking that the main power is disconnected, I like to keep one of these non-contact voltage testers with me to occasionally check items that may have stored energy or separate power sources.
6. Perform Work - The lockout tagout should remain in place until work is completed including if you leave for lunch, the night, or the weekend.
7. Remove Lockout and/or Tagout - Remove and do any testing required to place the machine back into service. Also make sure no additional tags should be put on the machine such as "Waiting on Engineering Approval" or "Waiting on Safety Review".
8. Communicate Again - Another commonly missed step, let people know when you are finished. If they know you tell them when you finish work, then they are less likely to try to start a machine before you come to them.