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. CALCULATIONS To calculate the pounds ( lb) per day the concentration is multiplied by the volume of air produced in one day. The lab reports the Concentrations (C) of the air sampling in ug/liter. The first step is to convert this value to lbs/cf (pounds per cubic foot) . y, 1 ug/l x 0 .000001g/ug x 0 .0022051g/g x 28 . 321/cf = 0 . 000000621lb/cf The volume of air produced in one day , equals the flow rate (Q)x the time of flow . V = Q x T = c£/day = cf/min x 1440min/day The volume must be corrected to standard temperature and pressure( STP) . P = Pressure = 14 . 7 lb/int @ STP V - Volume cf i T = Temperature in degrees above absolute Zero = 491 . 58-R @ STP . Using the Ideal Gas Law P1V1/T1 = P2V2/T2 Solving for V2 =P1V1T2/P2T1 Assuming Pl = P2 = 14. 7 Ib/int , P cancels from the equation leaving V2 = V1T2/T1 . V1 = Q cf/m x 1440 min/day T2 = 431 .58-R T1 = 459 .58 + T-F at sight . V2 = Q cf/min x 1440 min/day x 491 .58-R/ ( 459 .58- + T-F) X lb/day = C ug/l x 0 .0000000621 lb 1/ug cf x Q cf/min x 1440 min/day x 491 . 58-R/ ( 459 . 58- + T-F) Q for the Influent and Effluent samples = The well flow rate + the air flow . PILOT TEST Gasoline range hydrocarbons were known to exist beneath the pump island dispensers and undergound storage tank areas . The tank excavation and product dispenser areas were overexcavated and the ma]ority of contaminated soil was removed, aerated, and then used as compacted engineered fill for the excavations . Pea gravel was first used to backfill the excavations to the 12 foot depth followed by the compacted native soil to the surface. On October 8 and 9 , 1990 three vapor extraction wells were installed into these excavated areas to the 40 foot depth using 2 inch SCH 40 PVC with 0 .02 inch slot casing for the wells . R604 vapor , 7/31/92 , p . 7