Rule 1032. Reference test method 9C, opacity measurement for basic oxygen furnace operations and hot metal transfer and desulfurization operations at steel manufacturing facilities, reads as follows:
Fugitive and nonfugitive visible emission evaluation for basic oxygen furnace operations, hot metal desulfurization, and hot metal transfer operations shall be conducted as specified in reference test method 9, with the exception that the data reduction provisions of section 2.5 of method 9 shall be based on an average of 12 consecutive readings recorded at 15-second intervals.
Mich. Admin. Code R. 336.2032