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1Ja ,GRGUNDWATER TECHNOLOGY <br /> STANDARD OOCEDURE <br /> � CERNINGpOOPERATIONTING /CAMBRATION OF <br /> pgOT0-IONIZATIO'9 ANALYZER <br /> sop 19 <br /> The HNU Model 101 Photo-ionization Analyzer shall be used to <br /> -. measure the concentration of trace gases <br /> 000over <br /> a range of <br /> less than 1 part per million (ppm) <br /> to employing the principle of photo-ionization for detection. <br /> The specific instrument used for investigations related to. <br /> hydrocarbon contamination should be calibrated for direct <br /> readings in ppm volume/volume of benzene. This pacbahich <br /> field analyzer consists of two components: 1) probe <br /> contains a fan for moving air into the sensor, an ultra- <br /> violet light (provides ionization energy) , an ionization <br /> chamber and signal amplifier; Z) readout assem'nly which <br /> contains a battery, ion chamber bias, meter-readout and <br /> ; <br /> control panel. Specifics of the detection principle/theory E+; <br /> and functions of various components can be found in the E <br /> manufacture's instruction manual (RNLI Systems, Inc.) . i <br /> To assure optimum performance, the photo-ionization analyzer ; <br /> should be calibrated with a standard gas mixture of known <br /> s = concentration from a pressurized container. A daily <br /> procedure for calibration involves bringing the probeanin <br /> readout in close proximity to the calibration gas, <br /> the valve on the tank and checking the instrument reading. <br /> This provides a useful spot check for the instrument. <br /> A procedure conducted weekly for more accurate calibration <br /> s " of the instrument from a pressurized container is to connect <br /> one side of a "T" to the pressurized container of tha- } <br /> tion gas, another side of the "T" to a rotameter anndd e <br /> the , <br /> third side of the f1T11 directly to the 8-inch extension to <br /> the photo-ionization probe. Crack the valve of the <br /> - pressurized container until a slight flow is indicated on ; <br /> the rotameter. The instrument draws in the volume of sample <br /> required for detection, and the flow in the rotameter <br /> indicates an excess of sample. Now adjust the span pot '�o <br /> ; <br /> that the instrument is reading the -exact value of the f <br /> calibration gas. (If the instrument span setting is <br /> be turned back to. the standby <br /> changed, the instrument should <br /> position and the electronic zero should be readjusted, if <br /> necessary) • <br /> i <br /> lJ�' -i <br /> ^--�� GR6Cti1)H'ATER <br /> TEoi owcy.INC. <br /> w+ <br /> i <br /> i <br /> 1 <br />