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1 <br /> Vapor Extraction System Sample Calculations <br /> Moore Petroleum,Inc,1399 E Yosemite Ave,Manteca,CA <br /> ' VAPOR EXTRACTION SAMPLE CALCULATIONS <br /> ' Calculating Daily Extraction Rate <br /> Once given the vapor analytical results in ug/i and the corresponding system flow rate for that <br /> ' sampling event in cubic feet per minute(CFM), a daily extraction rate may be calculated in <br /> pounds per day(lb/day) <br /> ' The sample calculations will be focused on the sampling event which occurred on February 24, <br /> 1995 This sampling event yielded concentrations of total petroleum hydrocarbons(TPH), as <br /> gasoline, at 160 ugll, and a benzene concentration below laboratory detection limits The system <br /> tflow rate on this day was 16 1 CFM <br /> The method for calculating daily extraction rates is to take the analytical concentrations which are <br /> ' reported in ug/1 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, and then converted to units of days The result will be the daily extraction rate <br /> ' in lb/day An example of this method is as follows <br /> concentration (�`g}x 283171 x 1 Ib x'06w rate (±3 )x 1440 min=extraction rate( Ib} <br /> I ft 3 4 54x10 8µg rtun day day <br /> ' is applied to the TP as gasoline, concentrations the following daily extraction <br /> If flims method pp H, g g Y <br /> ' rate results <br /> 160 pg x 28 317/x 1 lb x16 1 ft3 x 1440 mm_ 0 23 lb TPH,as gasoline <br /> l ft3 4 54x10gµg mm day day <br /> ' Thus 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 TPK 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 he 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 />