Section R. 408.10955 - InspectionRule 955.
(1) A dry chemical extinguishing system shall be inspected by a trained and authorized employee or outside service:(a) Not less than annually to insure operability.(b) Not less than semiannually to insure the installed expellant gas containers are at the designed pressure or weight.(c) Not less than semiannually to insure the stored pressure dry chemical container is at the designed pressure.(2) A tag shall be affixed indicating the date of inspection.Mich. Admin. Code R. 408.10955