Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 211 - DEFINITIONS AND GENERAL PROVISIONS
Subpart B - DEFINITIONS
Section 211.1690 - Day

"Day" means for purposes of Part 218 or Part 219, the consecutive 24 hours beginning at 12:00 AM (midnight) local time or beginning at a fixed time consistent with the source's operating schedule, as provided below. A source may use a day beginning at a time other than midnight which is consistent with its operating schedule provided that the owner or operator of the source first notifies the Agency in writing of such alternative, describing why it would be more reasonable to maintain records on this basis. The owner or operator shall notify the Agency in writing prior to any change in the time at which a day begins.