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Comment by gxs | Hacker News Reader

Another one is machinery where you have to "enter" the machine to do maintenance. Think industrial ovens.

You're supposed to turn off the circuit breaker and lock it with your own personal lock that only you have the key to. That way no one can turn it on even if they wanted to.

I've heard no one, under any circumstances is allowed to take the lock off. If the person leaves after their shift and forgets to take it off for example, they have to come back in the middle of the night so to speak and take it off.

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As someone else mentioned, that's a lockout-tagout procedure. Very common when doing any kind of maintenance on a machine. You isolate the power sources and place a personal lock on it to which only you have the key. It usually has your name and an ID number written on it. The lock cannot be removed by anyone else. If you, for instance, forget to take your lock off and go home, it's a very long process where they have to get someone high enough up the chain to get in contact with you and either get you to come back or confirm that you're safely a long way away from the machine before they can cut the lock off. This makes your management very unhappy and most places that I've worked will write you up for leaving while the equipment is still locked out if maintenance is finished and it's safe to operate.

It's not only electricity that needs to be isolated and locked out. A lot of machines use air pressure to operate moving parts, so in that case you'd have to isolate all electrical sources as well as the air. The machines I usually mess with require 2 locks. Some of the machines I've seen can require 6 or more locks to be fully locked out and safe to work on.

When I served on a submarine, tagout procedures were followed to the letter.

A typical maintenance period might require 100 or so separate tagouts, each of which could require anywhere from one to dozens of tags. Each duty watch was required to show up early enough to go through the entire tagout book and at least know the gist of what was in progress.

Finding a loose tag was an automatic all hands all work stoppage, until it was tracked down and resolved. No questions, even if your work was in a different compartment, or had no logical connection to what he tag was for.

Each new tagout request had to be signed off on by at least three people, sometimes all the way up to the captain and not just a foreman or supervisor but one or more shop heads.

Seawater system tagouts on a floating sub were serious business.

Not just equipment you have to enter. This is used in situations with "stored energy" or other systems that need to be turned off or otherwise disabled for safe maintenance. There are multi-lock hasps that can be used if multiple people have overlapping needs to lock out the system, and other devices such as valve handles covers, etc., that help with locking out components don't have a built-in place for a lock.

I think this is called lock out tag out

https://en.m.wikipedia.org/wiki/Lockout–tagout

An example, not a nice way to go - https://www.bbc.co.uk/news/uk-england-merseyside-32050998

A recent one in US https://www.nbcnews.com/news/us-news/bumble-bee-pay-6-millio...

These make the worst horror stories I've read from various safety organizations. Tanks with gases (nitrogen is particularly sneaky), ovens, radioactive sources... If you want to learn about industrial risks based on real stories watch the CBS videos https://m.youtube.com/watch?v=f2ItJe2Incs

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