Michigan Compiled Laws, Chapter 339. Occupational Code § 339.5943

(a) A power boiler, process boiler, or high pressure high temperature water boiler shall receive a certificate inspection annually and shall be externally inspected annually, while under pressure, within 6 months from the date of the certificate inspection.

(b) A low pressure steam or vapor heating boiler shall receive a certificate inspection every 2 years.  A hot water heating boiler or hot water supply boiler shall receive a certificate inspection every 3 years.

(c) A grace period of 2 months beyond the periods described in subdivisions (a) and (b) may elapse between certificate inspections.

(d) On a case-by-case basis, as provided in rules promulgated by the department, the board may permit longer periods of up to 36 months between certificate inspections described in subdivisions (a) and (b).

(e) The chief inspector, a deputy inspector, or a special inspector shall perform the inspection of a boiler.

(f) If a hydrostatic test is considered necessary by the inspector, the owner or user of the boiler shall perform that test.

(g) A boiler, other than a cast iron sectional boiler, that is to be installed in this state shall be inspected during construction, as required by the applicable rules of the board, by an inspector who is licensed to inspect boilers in this state.  If the boiler was constructed outside of the state, the boiler shall have been inspected by an inspector who holds a license as an inspector of boilers for a state that has a standard of examination substantially equal to that of this state or a license issued by the National Board of Boiler and Pressure Vessel Inspectors.