(1) This chapter does not apply to boilers under federal control.
(2) The provisions of this chapter requiring inspections, inspection fees, and certificates do not apply to:
(a) steam heating boilers operated at not over 15 pounds per square inch gauge pressure in private residences or apartments of six or less families or to hot water heating or supply boilers operated at not over 50 pounds per square inch gauge pressure and temperatures not over 250 degrees F when in private residences or apartments of six or less families; and
(b) boilers constructed or maintained only as a hobby for exhibition, educational, or historical purposes and not for commercial use if the boilers have an inside diameter of 12 inches or less or a grate area of 2 square feet or less and are equipped with a safety valve, a water level indicator, and a pressure gauge.
(3) Persons operating any of the engines or boilers exempted from the operation of this chapter may not be required to procure a license from the department.