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1 <br /> Vapor Extraction System Sample Calculations <br /> t Moore Petroleum,Inc, 14800 W Frontage Road,Manteca,CA <br /> ' Calculating Daily Extraction Rate for Vapors <br /> Given the vapor analytical results in ug/l and the corresponding system flow rate for that sampling <br /> ' event in either cubic feet per nunute (CFM) or standard cubic feet per minute (SUM), a daily <br /> extraction rate may be calculated in pounds per day (lb/day) <br /> ' The sample calculations will be focused on the sampling event which occurred on August 16, <br /> 1995 This sampling event yielded concentrations of total petroleum hydrocarbons (TPH), as <br /> gasoline, at 1,900 ug/l, and a benzene concentration below laboratory detection limits The <br /> ' system flow rate on this day was 48 CFM <br /> The method for calculating daily extraction rates is to take the analytical concentrations which are <br /> ' reported in ug/l and, using standard conversions, convert this value to units of pounds per cubic <br /> foot This value may then be multiplied by the system flow rate on the day the sample was <br /> collected, in CFM or SUM, and then converted to units of days The result will be the daily <br /> textraction rate in lb/day An example of this method is as follows <br /> concentration (pg),28 3171X 1 lb xflow rateft3 )x 1440 min`extraction rate(' <br /> ate( lb) <br /> ft 3 4 54x10"pg nun day day <br /> ' If this method is applied to the TPH as gasoline, concentrations,the following daily extraction <br /> ' rate results <br /> µg 28 3171 1 lb f13 1440 min Ib <br /> 1,900 x x x4g x = 8 2 TPH,as gasoline <br /> I ft 3 4 54x10 8µg min day day <br /> ' This method can also be applied to the analytical results for benzene on this date Due to the <br /> benzene concentration being below laboratory detection limits, no benzene will be extracted on a <br /> daily rate <br /> ' Once the daily extraction rates are known, the cumulative quantities of TPH, as gasoline, and <br /> benzene need to be calculated It will be assumed that the average daily extraction rate for a <br /> ' particular period will lie somewhere between the most recent daily extraction rate and the <br /> previously calculated daily extraction rate It will be assumed that a good approximation of the <br /> average daily extraction rate for a particular period of time will be the most recent daily extraction <br /> ' rate averaged with the previously calculated daily extraction rate <br />