For each wet scrubber subject to the operating limits for pressure drop and scrubber water flow rates in § 63.9890(b), you must at all times monitor the hourly average pressure drop and liquid flow rate using a CPMS according to the requirements in § 63.9921(a).
Cross-references to the CFR
63.989063.9921
40 C.F.R. § 63.9920: What are my continuous monitoring requirements? | Justis AI