All chains (other than bridle chains attached to derricks or masts), rings, hooks, shackles, and
swivels made of wrought iron, which are used in hoisting or lowering, shall be annealed in accordance with 1919.36 at the following
Half-inch and smaller chains, rings, hooks, shackles and swivels in general use, at least once every
six months; and
All other chains, rings, hooks, shackles, and swivels in general use, at least once every twelve
In the case of gear used solely on lifting machinery worked by hand, twelve months shall be
substituted for six months in paragraph (a)(1) of this section and two years for twelve months in paragraph (a)(2) of this section.
When used in this paragraph, the term "in general use"means used on fifty-two or more days in a
year. In any case, however, the period between annealings shall not exceed two years.
Chains, rings, hooks, shackles, and swivels made of material other than wrought iron or steel shall be
heat treated when necessary in accordance with 1919.36(b).