A recent major cooling tower installation included a requirement for a very low drift rate guarantee and testing by the EPA stack gas sampling method 13A, modified on cooling tower application, and significant scatter in results have been reported. A study was commissioned with both Environmental Systems Corporation and Midwest Research Institute to conduct modified Method 13A, tests over a variety of eliminators. The tests were conducted under carefully controlled laboratory conditions in a large counterflow test cell. The results will be presented and compared to results from the same test cell using a 4th generation hot bead/filter pack isokinetic sampling systems.

90-12: Comparison of Two Isokinetic Drift Measurement Methods