7 Del. Admin. Code § app D § 1124-A-D-3.0
The overall emission reduction efficiency of the emission control system shall be determined each day as the product of the capture efficiency, as determined using the capture efficiency test method in this appendix, and the control device destruction or removal efficiency; or for each solvent recovery system, by the test protocol described in 1.2.3.1 of this appendix for comparing liquid input to liquid VOC recovery. The results of the capture efficiency test and control device destruction or removal efficiency test remain valid for each day until a subsequent test is performed. The results of any valid test may be used for each day until superseded by the results of a valid test subsequently performed.
7 Del. Admin. Code § app D § 1124-A-D-3.0