Combined vent stream,
Combined vent stream, as used in reference to batch process vents, continuous process vents, and aggregate batch vent streams, means the emissions from a combination of two or more of the aforementioned types of process vents. The primary occurrence of a combined vent stream is the combined emissions from a continuous process vent and a batch process vent.
Source
40 CFR § 63.1312
Scoping language
The following terms used in this subpart shall have the meaning given them in 63.2, 63.101, 63.111, 63.161, or the Act, as specified after each term: