OSHA
OSHA 1910.147 — Control of Hazardous Energy (Lockout/Tagout)
OSHA's lockout/tagout rule, for anything that can move or energize while someone is working on it.
OSHA's rule for the control of hazardous energy — lockout/tagout.
Open it when you're writing or reviewing lockout procedures for anything that can move or energize while someone is working on it: pumps, PTOs, air systems and shop equipment and machinery.
Read the current text on OSHA's site.