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Method Description The process is described in the following steps: 1. Probe Installation 2. Inoculation 3. Sample Collection 4. Sample Analysis 5. Report Probe Installation Two probe design options are offered for new construction facilities. Option#1 is available if the request is initiated prior to the installation. Schematics can be provided to the contractor that will allow the installation of a conduit system during the installation phase of the tanks and piping. The advantage to this method of installation is to avoid drilling into the brand-new concrete. This conduit will later be utilized by the technician for the collection of soil vapor samples(see sample collection below). This slotted-conduit pipe is laid into the pea-gravel horizontally,looping around each tank and along each piping trench. Conduit is terminated at a surface junction-box or within a sump containment. Option #2 is used if the project is initiated after the tank/piping installation has occurred or if the issue of drilling concrete is of non-importance to the contractor/tank owner. Option #2 involves the placement of vertical sampling probes, consisting of%" schedule 40 PVC are installed within ten horizontal feet of all possible leak locations. In situations where tank pits and piping trenches do not contain engineered backfill (pea-gravel),the sampling probes are installed within five horizontal feet of all possible leak locations. Tank probes are installed along the outer long-side of each tank, generally at a depth within two feet of the tank bottom(or just above the water table if applicable). Additional probes are installed near appurtenances along the tank ridge. Piping probes are placed along the product distribution, vapor recovery and vent piping trenches,generally at a depth of two feet below grade. Probes are installed by coring a hole in the pavement and inserting a sampling probe into the excavation zone of the tank or pipe using soft excavation techniques. The top of each probe is fitted with a PVC sampling cap that will be used later for soil vapor extraction. Inoculation Upon completion of the concrete pad, a technician will arrive on site and perform an inoculation event. Inoculation is the process of adding chemical tracer to the system to be tested. In active tank systems,tracer chemical is introduced into the fuel directly and dispersed throughout the piping through normal tank usage. Since the new tank systems lacks product at the time of the test, each tank and piping component will be isolated and inoculated independently with a predetermined amount of tracer and nitrogen mixture. Prior to inoculation it will be confirmed that if the site is under remediation. Soil vapor extraction systems, air- sparging systems and bio-venting systems must be turned off during the test phase(between inoculation and sampling). Copyright 2003 Praxair Services,Inc.