OSHA requires fall protection to be provided at: 4 feet in general industry; 5 feet in shipyards; 6 feet in the construction industry; 8 feet in longshoring operations; or any height when working over dangerous equipment and machinery. If you have workers working at or above these heights in the circumstances described, then you’re legally required to implement a suitable fall protection system.
OSHA regs are mandatory, but are only baseline standards and do not necessarily represent the most current thinking. ANSI voluntary standards represent the best of today’s thinking and each of us should keep “up to speed.”