When equipment or tools are being repaired, maintained or cleaned, the power source associated with the equipment is cut off. The device or tool will not start. At the same time, all energy sources (power, hydraulic, air, etc.) are shut off. The aim: to ensure that no worker or associated person working on the machine is injured.

It specifically refers to the establishment of safety procedures based on the above locks and hangings of different equipment and systems (such as domestic safety maintenance regulations and electrical maintenance operating regulations), so as to effectively control the dangerous energy, and implement the locking of the hangings to ensure the safety of personnel and equipment. In some European and American enterprises, in order to ensure the safety of maintenance, commissioning and engineering operations, LOTO system is widely used.
The card mentioned is the common "manned repair/operation, do not start/close" card.
The locks mentioned (special locks) include:
HASPS -- for locking;
BREAKER CLIPs -- For electrical lock:
BLANKFLANGES -- lock the water supply pipe (liquid pipe);
Valve overs (VALVECOVERS)- Valve locks;
PLUG BUCK -- ETS -- electrical appliances are used for locking, etc.