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Section No 6 <br /> Revision No 0 <br /> Date- September 5 , 1991 <br /> Page 8 of 55 <br /> 6 3 2 Sample Collection Equipment <br /> The apparatus used variously for passive or active collection of gas <br /> samples from subsurface, confined, or ambient environments will be <br /> specified in the sampling and analysis plan, based on such factors as the <br /> sampling environment, concentration and reactivity of the constituents, and <br /> required accuracy, precision and detection limits Equipment specifications <br /> are described below <br /> ■ Diaphragm Pump <br /> - 12 volt direct current with battery capable of 24-hour <br /> continuous pumping, <br /> - Diaphragm and valves constructed of non-lubricated Viton, <br /> - Maximum unloaded flow rate of 2 liters per minute, <br /> - Minimum adjustable flow rate of 1 milliliter per minute, <br /> - Discharge pressure greater than 15 pounds per square inch gage <br /> (psig) , <br /> - Ball check valve constructed of Teflon and responsive to <br /> pressure differentials down to a maximum of 1 psig <br /> ■ Flow Measurement <br /> Extend bypass variable-area flow meter constructed of <br /> borosilicate glass, <br /> - Scale is in milliliter (ml) of air per minute with major <br /> graduations every 5 m1 and minor graduations every 1 ml <br /> 6-8 <br />