Rule 1030. Reference test method 9A, opacity measurement for scarfer operations at steel manufacturing facilities, reads as follows: Visible emission evaluations for scarfer operations at steel manufacturing facilities 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 6 consecutive readings, recorded at 15-second intervals.
Mich. Admin. Code R. 336.2030