2.4 Locks, tags, hasps and lockboxes

1 The employer provides it

1910.147(c)(5)(i): "Locks, tags, chains, wedges, key blocks, adapter pins, self-locking fasteners, or other hardware shall be provided by the employer for isolating, securing or blocking of machines or equipment from energy sources."

Two things follow from this. First, no employee should be buying their own lock, which also means no employee should be told to "bring a padlock." Second, the list is broader than padlocks — chains, wedges, key blocks and adapter pins are named because isolation and blocking need hardware beyond a lock, and the employer owes that too. If a press needs safety props, the props are program hardware.

2 Five things every device must be

1910.147(c)(5)(ii) opens with three requirements that apply before you even get to the list: devices shall be singularly identified, shall be the only devices used for controlling energy, and shall not be used for other purposes. Then come the four named criteria.

"The only devices used for controlling energy" and "shall not be used for other purposes" together mean the lockout padlock is not the padlock that also secures the tool crib. Colour-coding does most of the work here: a plant where every energy-control lock is the same colour, and nothing else is that colour, has satisfied both the standardization and the single-purpose requirements in one decision.

"Identifiable" means a name, a photo tag or a stamped number that ties the lock to a person — not to a department. When a lock is found on a machine on Monday morning, the question is always "whose is it?", and 1910.147(e)(3) makes the answer matter.

3 The 50-pound tag rule

1910.147(c)(5)(ii)(C)(2) is unusually specific, and it is the paragraph to quote when someone hangs a tag on a piece of wire: tagout device attachment means "shall be of a non-reusable type, attachable by hand, self-locking, and non-releasable with a minimum unlocking strength of no less than 50 pounds and having the general design and basic characteristics of being at least equivalent to a one-piece, all-environment-tolerant nylon cable tie."

Four properties, then a benchmark. Non-reusable, so it cannot be taken off and put back. Attachable by hand, so nobody needs a tool. Self-locking. Non-releasable below 50 pounds. And the whole thing at least equivalent to a heavy nylon cable tie designed for any environment.

1910.147(c)(5)(iii) then tells you what the tag has to say: it "shall warn against hazardous conditions if the machine or equipment is energized and shall include a legend such as the following: Do Not Start, Do Not Open, Do Not Close, Do Not Energize, Do Not Operate." A tag that only carries a name and a date does not meet this — the warning legend is part of the requirement.

4 Hasps, lockboxes and the hardware that makes multi-person work possible

Nothing in 1910.147 names a hasp or a lockbox, but the requirements make both inevitable. 1910.147(d)(4)(i) requires a device on each energy isolating device, applied by the authorized employees. 1910.147(f)(3)(ii)(D) requires each authorized employee in a group to affix a personal device to the group lockout device, group lockbox, or comparable mechanism. Between those two, you need hardware that lets several personal locks secure one point.

1. 1
   Scissor hasp — fits through a disconnect handle and accepts several padlocks; the handle cannot move until the last lock comes off.
2. 2
   Group lockbox — the operations locks securing each isolation point are opened by keys placed inside; each worker's personal lock on the box means nobody can retrieve a key.
3. 3
   Valve lockouts — gate valve covers, ball valve clamps, chain-and-clamp arrangements, plug and pneumatic line lockouts. These are what turn "the valve has no hole" into a valve that is capable of being locked out.
4. 4
   Blocks, props and pins — the "otherwise disable" hardware of 1910.147(a)(3)(i), rated for the load they hold.

5 Keys, master keys and the one question that settles it

The standard does not mention master keys, but 1910.147(e)(3) does the work indirectly: each device shall be removed by the employee who applied it, with the exception available only under a documented procedure that includes verifying the employee is not at the facility and making all reasonable efforts to contact them. A supervisor with a master key that opens everyone's locks turns that requirement into a formality.

The question that settles most hardware arguments is this: can this lock be removed by anyone other than the person who put it on, without the documented removal procedure being followed? If yes, the lock is a symbol. Keyed-different locks with a single key per lock, held by the person who applied it, are the arrangement that makes the standard's promise true.

6 A hardware audit you can run in an hour

Everything above turns into a short walk with a clipboard. Answering these seven questions honestly finds most hardware gaps in a plant:

Hardware is the cheapest part of a lockout program to fix and the easiest to demonstrate. It is also, when it is wrong, the fastest thing for an inspector to see from twenty feet away.