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AR226-2147 INTEROFFICE HEMORAKDuH TO: J. Ronald Layton CC: PAT DUMCAN CC; ROBERT S. FRENCH CC: ROBERT L RITCHEY Date: From: 19-0ct-1994 09;05pro Roger J. Zipfel ZIPFEL Dept: PPD-SPD Tel No: 304-863-2567 s ( LAYTONJR AT Al AT CFOC ) g --* Ln ( DnNCANPJ AT Al AT CFOC ) ( FREMCHRS AT Al AT SPOC2 ) oo e ( RITCHERL AT ISCDCVM1 ) Subject: RE: AIR VELOCITY IN CF STACKS Ron, thanks for sending me the data on your vent systems. Our current vent stacks emitting C-8 are approximately 60 feet in the air with an air flow of 5000 CFM in a 20 in. Dia stack- Our C-8 concentration ranges from 100-150 PPM. With these conditions we can generate small areas of exposure above the community exposure guideline of 0.3 micro grams per cubic meter (actual level is 120% of the CEG.). For this reason and for C-8 recovery reasons we have chosen to install scrubbers on these stacks. The conditions you have given me for the stacks at the Kinston site we have the following conditions. riormal case is 4500 CPU in a 34 in. Dia stack. Stack height is 45 feet. Stack concentration would be approximately 100 ppb. ( I calculated on 4500 cfni of air at 0.075 Ibs/cubic foot, and 20 pounds per year drier). this based C-8 per Based of our stacks your vent velocity is 1/3 of ours, your height is lower than ours but your concentration is 1000 times less than ours. Therefore, even if your dispersion were only 10% of ours your six driers would still be below 10% (actually calculated 7% ) of the CEG. This is a very safe operating range and requires no downstream abatement.' This level is so far below any point of concern that exhaustive dispersion modeling of your stacks ( to improve on my estimate) is not warranted at this time. It is my opinion that you need monitoring at your site. One thing that we have done at to operate the driers slightly do this? When we operate above operating areas giving us high to do no additional work on C-8 analysis or our site to keep local exposures to a minimun is below atmospheric pressure. "Will you be able to atmospheric conditions C-8 does escape into the C-8 levels. However, here levels never exceeded EID951807 .J times the &EL. Here again your 1000 X less useage of problem to be very small. If you wish to proceed with more detailed calculations, you in these. C-8 would make this I will gladly assist Roger. ps., I solicit opinions from all addresses of this memo. EID951808