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Soil Gas Sampling — PRT ISSystem Operation <br /> Probing <br /> Drive the PRT tip configuration into the ground. Connect <br /> probe rods as necessary to reach the desired depth. After <br /> t depth has been reached,disengage the expendable point by <br /> t pulling up on the probe rods. Remove the pull cap from the <br /> jtop probe rod,and position the Geoprobe unit to allow room to <br /> Probe Rod work. <br /> I I Connection <br /> I j , 1. Insert the adapter end of the tubing down the inside <br /> I : diameter of the probe rods(Figure 2). <br /> Tubing <br /> 2. Feed the tubing down the rod bore until it hits bottom on <br /> the expendable point holder. Allow about 2 ft. <br /> (610 mm)of tubing to extend out of the hole before cutting <br /> ft: it. <br /> 3. Grasp the excess tubing and apply some downward <br /> pressure while turning it in a counterclockwise motion to <br /> PRT Adapter engage the adapter threads with the expendable point <br /> t holder(Figure 3). <br /> 0-Ring <br /> 4. Pull up lightly on the tubing to test engagement of the <br /> threads. (Failure of adapter to thread could mean that <br /> intrusion of soil may have occurred during driving of probe <br /> rods or disengagement of drive point.) <br /> i. <br /> #b „ <br /> t# PRT Expendable <br /> • Point Holder <br /> 0-Ring <br /> 1 x <br /> s. <br /> Expendable <br /> Drive Point <br /> A cross section of probe rods driven to <br /> depth and then retracted to allow for <br /> soil gas sampling.The PRT adapter <br /> and tubing are now fed through the <br /> rods and rotated to form a vacuum- <br /> tight connection at the point holder. <br /> The result is a continuous run of <br /> tubing from the sample level to the <br /> surface. <br /> The Tools for Site Investigation ®' <br /> '¢ •a:t ' yf5'.':i... �Y :.L7:: ..tt✓✓11 O': r' A::;+' 0 <br /> WU <br /> D.3 <br />