(1)(a)A cylinder exposed to fire shall not be used unless it has undergone proper examination and hydrostatic or hydrostatic stretch test.(b)If deleterious structural changes in the material due to the action of heat of the fire are apprehended to have taken place, the cylinder shall have to be subjected to proper heat treatment, followed by hydrostatic test or hydrostatic stretch test, as the case may be, before the cylinder is taken into use.
