Lockout-Tagout Device

A lockout-tagout device is the physical lock, tag, or block used to carry out lockout-tagout procedure, the industrial safety practice of shutting off a machine's energy sources before maintenance or repair work begins and physically preventing anyone from switching that energy back on until the work is finished. A worker isolates each energy source feeding the machine, electrical, pneumatic, hydraulic, or stored mechanical energy such as a raised part or a compressed spring, then places a personal padlock through a lockout device fitted over the switch, valve, or breaker, and attaches a tag naming the worker and the reason for the lockout; only that worker's own key removes the lock. The practice exists because machinery that appears off can still be reenergized by someone else, or restart on its own from a control fault or stored energy, while a person's hands or body are inside it, and mandatory lockout-tagout rules, such as those enforced in the United States under occupational safety regulation, followed a documented history of exactly that kind of accident during maintenance work.