Machine guarding is a precautionary safety feature on manufacturing or other engineering equipment.
Specifically, it is a shield or device covering hazardous areas of a machine to prevent contact with body parts or to control hazards like chips and noise from exiting the machine.
Machine guarding provides a means to protect humans from injury while working nearby or while operating equipment. Machine guarding is often the first line of defense to protect operators from injury while working on or around industrial machinery during normal operations.
When equipment maintenance is required, machine guarding in the form of electronic interlocks, light curtains, and/or physical barriers can provide level of protection that is adequate and compliant with OSHA in many cases. When servicing or maintenance requires the operator or maintenance employee to place their body in harms way of the moving parts where unexpected restart or reenergization could cause injury or death, then a full system shutdown is required by utilizing a method called lockout-tagout. Globally, this term is more often called, hazardous energy control.
The link between machine guarding and hazardous energy control is very strong. If the machine guarding is optimally engineered and utilized, then lockout-tagout will only be needed in less frequent instances of installation/removal or major maintenance. Conversely, if the machine guarding solution and machine control options are poorly engineered, then lockout-tagout procedures will be required to be utilized more regularly in order to ensure the safety of the worker.
Lockout-tagout is referred to in OSHA's CFR (certified federal regulation) 1910.147.
Machine Guarding is referred to in OSHA's CFR 1910.212.
In the UK machinery safety is covered mainly by 'The Provision and Use of Work Equipment Regulations 1998' (PUWER 98). These Regulations require that risks from machinery are controlled by engineering means where it is practicable to do so (regulation 11); that is to say by providing suitable guards, protection devices, warning devices and system control devices such as emergency stop buttons. In all circumstances these safeguards must be properly maintained (regulation 5) and appropriate information, training, instruction and supervision must be provided.