Document zoKZVBR6rQRp47xzqOvMpJRxR

TEXAS AIR CONTROL BOARD JOHN 1. BLAIR Chiirman CHARLES R. JAYNES Vice Chairman BILL STEWART, P. E. Executive Director 6330 HWY. 290 EAST AUSTIN. TEXAS 78723 512/451-5711 WILLIAM N. ALLAN VITTORIO K. ARGENTO, P. E. FRED HARTMAN D. JACK KILIAN.M. 0. OTTO R. KUNZE, Ph. 0.. P. E. FRANK H. LEWIS WILLIAM D. PARISH May 20, 1980 Mr. J. F. Erdmann, P.E. Union Carbide Corporation Chemicals & Plastics P. 0. Box 471 Texas City, Texas 77590 J. F. E. Re: TACB Account No. GB-0076-J Dear Mr. Erdmann: This letter is in response to your request of January 21, 1980, for a variance from the sampling schedule specified in Part 61, National Emission Standards for Hazardous Air Pollutants (NESHAPS), Subparts A and F and Appendix B, Methods 106 and 107. It Is your opinion that the requirements of this regulation are much more stringent than necessary because your process differs from that commonly found In Industry at the time this regulation was enacted. The data included in your report supports this opinion. There are some questions about the accuracy of the statistical evaluation of this data. Of primary concern is the assumption that the data follow a normal distribution. The mean and standard deviation reported do not indicate that this assumption is valid. The source of your statistical treatment, Engineering Statistics and Quality Control by Irving J. Burr, emphasizes this assumption hy placing it in italics which indicates it must be necessary before this treatment can be used. Secondly, we are not sure that sampling the same day every week could be considered random samplIng. Although your proposed sampling plan is not acceptable for the above reasons, the TACB realises that some variance is in order. Since your data does not follow normal distribution, however, a more pragmatic approach to determining new sampling requirements may be necessary. ucc 051466 Mr. J. F, Erdmann, P.E. May 20', 1980 Page 2 We will be glad to discuss this matter further at your convience. If you have any questions please give Mr. Charles Shevlln of my staff a call at 512/451-5711, Ext. 251. Sinrprplv_ James B. Draper, P.E., Chief Source Evaluation Section cc: Howard Houston, Compliance Division Sabino Gomez, Regional Supervisor, Bellaire ucc 051467