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OSHA prefers employers use lockout procedures. When equipment can be locked out, employers are expected to use lockout procedures. As such, tagout should only be used if the energy isolating device is not capable of being locked out.
OSHA does allow tagout to be used even if the equipment will accept lockout. To do this, employers must be able to demonstrate that their tagout system provides “full employee protection.”
The tagout device must be attached at the same location that the lockout device would have been attached and additional steps must be taken, as necessary, to provide a level of safety equivalent to that provided by lockout. OSHA says to use “additional safety measures such as the removal of an isolating circuit element, blocking of a controlling switch, opening of an extra disconnecting device, or the removal of a valve handle.” These steps reduce the likelihood of an unexpected start-up.
These additional steps must be detailed in the documented tagout procedure for the affected machine.
Often, tagout is required on older equipment. However, when this equipment is replaced or major repair, renovation, or modification is made, the energy isolating devices must be upgraded to accept lockout.
Also, whenever new machines or equipment are installed, they must accept lockout.