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AY 12 '97 12 : 15 FROM VEEDER-ROOT SERVICE TO 915104205890 PAGE . 002i008 Results of U.S. EPA Evaluation Automatic Tank Gaugingt (ATGS) Continuous Statistical Leak Detect Method (CSLD) This form tells whether the automatic tank gauging system (ATGS) described below used in a continuous statistical leak detect(CSLD)mode complies with the performance requirements of the federal underground storage tank regulation. The evaluation was conducted by the equipment manufacturer or a consultant to the manufacturer according to the 'Alternative Test Procedure Deemed Equivalent to EPA's." The full evaluation report also includes a form describing the method and a form summarizing the test data. Tank owners using this leak detection system should keep this form on file to prove compliance with the federal regulations. Tank owners should check with State and local agencies to make sure this form satisfies their requirements. ATGS Description Name TLS Series 300/400 onitorina SVStems with "LO .- Version Number 8472 Cagacii ncp, Prabe/8473 Maonetostrictive Probe Vendor Veeder Root 125 Powder F r Driv P.O. ox 2003 (street address) Simsbury Q T 0 70- 203 1- (city) (state) (zip) (phone) Evaluation Results This ATGS, which operates in two modes depending on the specified probability of detection of a leak rate of 0.20 gallon per hour, declares a tank to be leaking when the measured leak rate exceeds a threshold designed for the chosen mode. The threshold, probability of false alarm, P(FA), and probability of detection, P(D), of detecting a,leak rate of 0.20 gallon per hour, are given in the table below for the two modes of operation. Threshold Probability of False Alarm WA) Probability of Detection (P(D)l 0.17 <0.1% 95% 0.16 <0.1% 99% The minimum water level (threshold) in the tank that the ATGS can detect is 1.32 inches for the magnetostrictive version #8473 probe and 1.52 inches for the capacitance version#8472 probe. The minimum change in water level that can be detected by the ATGS iso 024 inch for the magnetostrictive version #8473 probe and Q Q27 inch for the capacitance version #8472 probe. Based on these results, the method 0 does 13 does not meet the federal performance standards established by the U.S. Environmental Protection Agency of 0.20 gallon per hour at P(D) of 95% and P(FA) of 5%. Test Conditions During Evaluation The data evaluation set included data from tanks of the following sizes Tank Size (gallons) < 51000 51000-91500 9,600- >20,000 Total # of 19,900 Records Number of Records 1 0 5 25 16 46 aw•1r+A P+Ct f1 RA,.s6a...d Dnw..1s.+ C.+�.—. ....Oman � AF Z