OSHA International The general Standards at 29 CFR 1910 :

The general industry standard, 1910.28(b)(1)(i), states that employers must ensure that each employee on a walking-working surface with an unprotected side or edge that is four feet or more above a lower level is protected. The four factors OSHA recommends include management commitment and employee involvement, worksite safety analysis, hazard prevention and control, and safety and health training. “Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.

Where does OSHA 1910 apply?
All workplaces the general standards at 29 CFR 1910 are applicable at all workplaces unless specifically prohibited or pre-empted by a specific standard which is directly related to the ongoing employee activities.