(225 ILCS 710/34) (from Ch. 96 1/2, par. 4242)
    Sec. 34. All boilers used for generating steam in and about mines shall be kept in good order, and the operator or superintendent shall have them examined and inspected by a qualified person, not a regular employee of said operator, as often as once in six months, and oftener if the inspector shall deem it necessary. Provided, that inspection by any boiler insurance company in good standing shall be considered equivalent to an examination by such qualified outside person. The result of such examination, of the person making such examination, shall be certified in writing by the operator to the inspector within 30 days thereafter. It shall be the duty of the operator to provide each boiler with a safety valve of sufficient area for the steam to escape, and with weights or springs properly adjusted and with a steam gage and water gages; and another steam gage shall be attached to the steam pipe in the engine house. All steam gages shall be placed in such position that the engineer or fireman can readily examine them and see what pressure is carried. All steam gages shall be kept in good order, and shall be tested and adjusted as often as once in every six months and their condition reported to the inspector in the same manner as the report of the boiler inspection.
    Every receiver, tank, or other receptacle, except transmission pipe, used for storing compressed air at a greater gage pressure than 40 pounds per square inch, which has a capacity exceeding 6 cubic feet, shall be capable of withstanding a gage pressure of 50 per cent greater than that normally allowed by the safety valve to exist in such receptacle. Every such receptacle shall be inspected with the same frequency and in the same manner as herein provided for the inspection of boilers. Every such receptacle shall be blown out at least once in every 24 hours, so as to remove all accumulations of grease, oil, or other material likely to cause an explosion. In no such receptacle shall the temperature be allowed to rise above 250 F.
    It shall be the duty of the operator to carry out the provisions of this section, and failure to comply with the provisions of this section shall constitute a violation of this Act.
(Source: Laws 1921, p. 525.)