A common cause of fatal or serious accidents at work is when a machine is accidentally started up while maintenance or repair work is still being carried out on it. To prevent unintentional start-up, there is a standard known as “lockout-tagout” (LOTO), which originated in the USA. This involves fitting electrical switches, ball valves, valves, etc. with special LOTO devices that prevent the control element from being moved. To prevent unauthorized removal of the device, each person involved in the work attaches a personal padlock to which no second person has a key. Once the work is complete and the machine can be restarted, the padlocks are removed.
LOTO not only protects workers during work, but also before work begins. This is because a document assigned to each machine lists all the hazards posed by the machine. These can be electrical, pneumatic, hydraulic, thermal, and chemical in nature, among others. In addition, all the steps necessary to safely shut down the machine are outlined. We also recommend labeling the individual lockout points so that the right one can be found quickly in complex systems with many ball valves and valves.
It is also important to attempt to start the machine after it has been taken out of service, known as a tryout or second “TO.” If the LOTO measures were successful, the machine must not show any signs of activity.