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07/13/2016 • <br /> C&S Cleaners Site Work Plan <br /> EX-2 through EX-4 will be abandoned during installation of the sub-slab venting system. EX-1 will be <br /> used as part of the sub-slab venting system. <br /> Sub-slab monitoring points will also be abandoned by sealing.The surface completion for each well and <br /> sub-slab monitoring point will be grouted flush to the grade. <br /> Task#2 Installation of Sub-Slab Venting System <br /> A passive sub-slab venting system will be installed in accordance with the attached Figures 1 through 4. <br /> This venting system was designed such that all piping will be run below or within the building slab, or <br /> along exterior walls of the building to preclude inadvertent tampering by current or future building <br /> tenants.The venting system will consist of approximately 6 feet of horizontal perforated piping to be <br /> installed in the shallow sub slab in the immediate vicinity of the dry cleaning machine and existing well <br /> EX-1,which will be connected to a rooftop vent.A connection will also be made to existing soil vapor <br /> extraction well EX-1 to provide additional venting. <br /> Both EX-1 and the horizontal perforated vent pipe will be connected to the rooftop vent via separate <br /> solid PVC pipes which will run beneath the slab and up the exterior of the building.Sub-slab vent pipe <br /> installation will be performed by saw-cutting the concrete along the alignment of the proposed trench <br /> and digging to approximately 7-inches below the bottom of the slab to allow space for pipe installation <br /> and bedding material, with the exception of the vent pipe to be installed between the dry cleaning <br /> machine and the east wall (shown in purple on Figure 3).A heavy duty plastic liner or geotextile fabric <br /> will be placed above the bedding material and new concrete will be poured and finished to match the <br /> existing grade.A protective and aesthetic covering for the piping (e.g., a rain gutter downspout or <br /> similar covering)will installed by the building owner where is the piping is visible on the exterior of the <br /> building. <br /> In addition, approximately 3 to 5 feet of perforated vent pipe also will be installed between the dry <br /> cleaning machine and the eastern wall of the facility (the approximate location of the proposed piping <br /> shown in purple on Figure 3). Access to this area is too limited to allow for concrete cutting and trench <br /> installation. Given the limited site access to this area,this vent piping will be installed by driving steel <br /> slotted pipe (1-to 2-inch outer diameter)directly into the sub-slab gravel material directly beneath the <br /> concrete slab. This section of pipe will be connected to the other venting pipe described above using <br /> air-tight fittings. <br /> Excavated soil will be stored on-site in a secure location in 55-gallon drums.Soil will be characterized for <br /> disposal at the nearest landfill and off-hauled as soon as possible following receipt of sampling results. <br /> The connection to EX-1 will be performed by cutting the well casing and inserting a tee approximately <br /> 10-inches below grade. Once the connection has been made the existing well box with bolting cover will <br /> be replaced to provide access to the wellhead for future abandonment. <br /> At the rooftop, the conveyance pipes will manifold into a single pipe which will connect to a wind <br /> turbine vent fan.Supports and protection will be installed as needed to secure the piping and vent fan. <br /> Page 4 of 5 Terraphase Engineering Inc. <br />