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Vapor Extraction System Sample Calculations <br /> Moore Petroleum,Inc.,5491 'T"Street,Banta,CA <br /> VAPOR EXTRACTION SAMPLE CALCULATIONS <br /> ! r <br /> L Calculating Daily Extraction Rates <br /> Once given the vapor analytical results in ug/l 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 <br /> the sampling event which occurred on September 19, <br /> 1995. This sampling event yielded concentrations of total petroleum hydrocarbons(TPH),,as <br /> r gasoline, at 1,500 ug/l, and benzene concentrations at 39 ug/l. The system flow rate on this day <br /> 1. was 10 CFM. <br /> rThe method for calculating daily extraction rates.is to take the analytical concentrations which are <br /> reported in ug/l g/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 /> L.� <br /> concentration (ug)x 28.3171x 1 lb x t3 ow rate x 1440 min <br /> 1 ft 3 4.54x10 gµg (rrnn) arm, =extraction rate( b ) <br /> day <br /> If this method is applied to the TPH, as gasoline,'concentrations; the following daily extraction <br /> rate results: <br /> 1,500 jig x 2 8.3 17 l x 1 lb X10 ft 3 x 1440 min.l lb= 1.3 TPH as gasoline <br /> ft 3 4.54x10 8µg min day day <br /> This method may also be applied to the benzene concentrations present in the vapor sample: <br /> 39 tgx 28.317 1x 1 lb x 10 ft3 x 1440 nun lb <br /> l = 0.035 Benzene <br /> ft 3 4.54x10 8µg min day day <br /> Once the daily extraction rates are known,the cumulative quantities of TPH, as gasoline, and <br /> benzene can 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 sufficient approximation of <br /> the average daily extraction rate for a particular period of time will be the most recent daily <br /> extraction rate averaged with the previously calculated daily extraction rate. <br /> L <br /> i <br />