Document DvNdQ4O6y0Rxq5oQ6R5QwnLNn

P) EsnniSKEDtcox E. I. du Pont de N emours & Company INCORPORATED p, O. Box 1217 P a r k e r s b u r g , W . V a . 26101 POLYMER PRODUCTS DEPARTMENT AR226-2138 CC: R- J. Burger D. A. Erdman L. W. Goin E . D . Johnson j . F . Hunt R. J. Zipfel C. A. Robinson j. F. Doughty ; P. Thistleton J. G. Loschiavo J. H. Hale - D-12190 H. Fernandes - L1380 File: 1.1.7.4 May 21, 1981 T0: FROM: K. I. WEVODAU, JR. WILMINGTON - L13W26 U-AA, 2.1 ft! A V A. R. BEHNKE WASHINGTON WORKS C-8 CONCENTRATIONS AND REQPIREP EXHAUST STACK HEIGHTS - FEP The height of our existing exhaust stacks from the coaaulator and wet finishing bag filters and the blender pit exhaust are low and fail to meet the normal of beina 1 3 to 2 times the buxldxng hexght (I.idustrxal Ventilation) In addition, the stacks are lower than the tops of equipment pieces in the immediate areaJ^ational^limatic and the prevailing wind direction, from the Nntxonal Clxma Center, would carry the exhausts toward our H & V xntakes (See Attachment 2). From our area axr samplxng, we are suspicious of recycling exhausted C-8 back xnto the buxldxng. Ihis is in addition to any C-8 which we would recexve from the Fine Powder Dryer exhausts (since the normal prevaxlxng wind direction is from FEP to Fine Powder). We have just completed a series of exhaust stack discharge samples. The bag filter exhausts were sampled directly while the blender pit exhaust level xs based on values measured in the pit. To be conservative, the recent C-8 exhaust samples have been multiplied by a safety factor to dispersion in the future- The hxghest experxmental value i l lfor Teflon FEP 100 in the wet finishing bag fxlter exhaust been multiplied by a factor of 2 (Table ARB--I)- The average of the coagulator bag filter exhaust samples has been multiplied by a factor of 2 (Table ARB-I). The additional data required to do the dispersion calculations is also contained in Table ARB-I. There's a world of things we're doing something about EID924499 AJP002533 R. I. WEVODAU, JR. 2- - MAY 21, 1981 Our initial goal is to recycle less than 0.05 MPB C-8 (1/10 AEL) back into the building through our H & V system. The low recycle along with other engineering controls within the building must reduce our C-8 levels to 1/2 AEL (0.27 MPB) by 1/1/82 in FEP. The selection of the 41* 0" elevation for calculation purposes is based on this level beingJ-*1 lowest elevation above all but one H & V inlets xn the FEP Area. Our largest unit is located on the 16* 0" roof with the top of its inlet at approximately 26' 0" above grade (See Attachment #2) . Please calculate the following cases assuming the worst wind and weather conditions using the C-8 concentrations given in Table ARB-I and provide C-8 isopleths for each case: CASE I C-8 concentration at 41' 0" above grade (top _ of all H & V inlets except Clean Room Make-Up Air) with present stack heights realizing that the program cannot account for turbulence from building and equipment interferences. See Table ARB-I. Fine Powder Dryer exhausts not considered. CASE IX ' Concentration at 41* 0" above grade with the existing exhaust stacks extended a nominal 6 feet above the tops of the individual bag filter houses and with discharge velocities increased to the 2500 - 3500 FPM range (See Table ARB-I). Fine Powder Dryer exhausts not considered. CASE III - If CASE II concentrations are above 0.05 MPB at " " the 41' 0" elevation, determine the stack height required to achieve a C--8 concentration below 0.05 MPB at the 41' 0" elevation. Fine Powder Dryer exhausts not considered. CASE IV - Please rerun Loschiavo's After May Shutdown Case for concentrations at 26' 0" and 41' 0" above grade using the exhaust contribution from the Fine Powder Dryersunder the worst wind/weather conditions for FEP. (Wind from east). AJP002534 EID924500 R. I. WEVODAU, JR. 3 MAY 21, 1981 The low discharge velocity on the coagulator bag filter discharge and the blender pit exhaust will be increased to the ''"3000 ft./min. advised in Industrial Ventilation by placing reducers at the discharge point or increasing volumetric air flow. We would appreciate any other advise you would have to offer. Please call me on 863-2291 if you have any problems or questions. We would appreciate getting the results within the next 2 - 3 weeks. Thanks for your cooperation. Attachment A R B /n sw AJP002535 EID924501