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calculations performed in the computer program or performed by hand and any assumptions used will be presented for review with the data and pilot test results In addition to estimating the minimum required number of extraction wells using the radius of influence, the required number of wells will also be determined based on the required volume of air needed to achieve remediation through volatilization in a given length of tune (TR) This calculation presented by Johnson & Ettinger (1993) determines the number of wells required(Nw)based on estimated saturated hydrocarbon vapor concentrations Wa), an estimated mass of contaminant to be removed(Mcont), and feasible single well flow rate (Qwell - determined from the step tests) NW=(a Mcont)/(Qwell TR) The two estimates, determined using the radius of influence and using the above-referenced equation,have inherent limitations and sources of error However, the results will be compared to estimate a reasonable number of vapor extraction wells and well spacing Placement of the additional vapor extraction wells, if required, will depend on the location of existing utilities,buildings, and other site constraints Flows and vacuums may need to be modified to ensure complete coverage of the area to be remednated It must be recognized that the pilot tests and calculations are performed to provide a basis for the system design The actual system configuration may be modified from the design based on continual evaluation of operating data once the system is installed On-gomg system evaluation will be an important part of the remedial action References Buscheck, T E & Peargin, T R (199 1) Summary of a nation-wide vapor extraction system performance study In Proceedings of the Petroleum hydrocarbons and Organic Chemicals in Ground Water Prevention, Detection, and Restoration November 20-22, 1991 National Water Well Association, p 205-219 Dupont, R R (1993) Fundamentals of bnoventing applied to fuel contaminated sites Environ Progress, Vol 12, No 1, p 45-53 Johnson, P C (1992) hyperventilate Users Manual, A Software Guidance System Created for Vapor Extraction Applications United States Environmental Protection Agency, EPA 500-C-B-92-001 US Gov't Printing Office 34 pp Johnson, P C & Ettinger, R A (1994) Considerations for the design of in situ vapor extraction systems radius of influence vs zone of remediation Ground Water Monitoring & Remediation, Vol XIV, No 3 p 123- 128 Johnson, P C , Kemblowski, M W , et al (1990) Quantitative analysis for the cleanup of hydrocarbon- contaminated soils by m-situ venting Ground Water,Vol 28,No 3 Johnson, P C (1992) HyperVentnlate Users Manual, A Software Guidance System Created for Vapor Extraction Applications United States Environmental Protection Agency, EPA 500-C-B-92-001 US Gov't Printing Office 34 pp CLEARWATER GROUP(SVE TEST) 3 revised June 29, 2001