Also called control of hazardous energy, lockout, CSA Z460
What is lockout and tagout?
Physically isolating a machine’s energy and locking it, so it cannot start while somebody is inside it.
What else it is called
- Other names
- control of hazardous energy, lockout, CSA Z460
- In French
- cadenassage
Related entries
Understanding lockout and tagout
Isolating every energy source on a machine - electrical, pneumatic, hydraulic, gravitational, thermal, stored mechanical - locking each isolation point with a lock whose key is held by the person at risk, and tagging it to say who applied it and why. Where several people are working, each applies their own lock, so the machine cannot be restored until the last of them has removed theirs.
In Canada occupational health and safety is provincial, so the specific regulation and its wording depend on where the plant is, while the technical standard generally referenced is the Canadian Standards Association’s standard on the control of hazardous energy. Written procedures are required per machine rather than in general, which is the requirement most commonly found missing in an inspection.
The rule that matters most is the one that gets broken under time pressure: the person exposed holds their own lock, and no supervisor, no maintenance lead and no shift change may remove it on their behalf. Every serious incident investigation in this area turns on that sentence.
In practice
A maintenance task that takes two minutes is where this gets skipped, and where the serious injuries happen. The written procedure exists for the two-minute job.
Frequently asked
Is a tag enough without a lock?
Only where a lock is genuinely not applicable, and then with additional measures, because a tag is a warning and a lock is a barrier. Treating tagout as a routine substitute for lockout is a finding waiting to happen.
Do we need a written procedure for every machine?
Effectively yes. A general policy does not tell a millwright which six isolation points this press has and in what order. Machine-specific procedures, posted at the machine, are both the regulatory expectation and the only version that gets used.