EPA Method 25A Determination Of Total Gaseous Organic Concentration Using A Flame Ionization Analyzer
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ID： |
7EB792CC67A1422FBAE0520C7CD60AEB |
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文件大小(MB)： |
0.08 |
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页数： |
14 |
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文件格式： |
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日期： |
2000-2-12 |
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购买： |
文本摘录（文本识别可能有误，但文件阅览显示及打印正常，pdf文件可进行文字搜索定位）：
1250,METHOD 25A - DETERMINATION OF TOTAL GASEOUS ORGANIC,CONCENTRATION USING A FLAME IONIZATION ANALYZER,1.0 Scope and Application.,1.1 Analytes.,Analyte CAS No. Sensitivity,Total Organic,Compounds,N/A < 2% of span,1.2 Applicability. This method is applicable for the,determination of total gaseous organic concentration of,vapors consisting primarily of alkanes, alkenes, and/or,arenes (aromatic hydrocarbons). The concentration is,expressed in terms of propane (or other appropriate organic,calibration gas) or in terms of carbon.,1.3 Data Quality Objectives. Adherence to the,requirements of this method will enhance the quality of the,data obtained from air pollutant sampling methods.,2.0 Summary of Method.,2.1 A gas sample is extracted from the source through,a heated sample line and glass fiber filter to a flame,ionization analyzer (FIA). Results are reported as volume,concentration equivalents of the calibration gas or as,carbon equivalents.,3.0 Definitions.,3.1 Calibration drift means the difference in the,measurement system response to a mid-level calibration gas,1251,before and after a stated period of operation during which,no unscheduled maintenance, repair, or adjustment took,place.,3.2 Calibration error means the difference between,the gas concentration indicated by the measurement system,and the know concentration of the calibration gas.,3.3 Calibration gas means a known concentration of a,gas in an appropriate diluent gas.,3.4 Measurement system means the total equipment,required for the determination of the gas concentration.,The system consists of the following major subsystems:,3.4.1 Sample interface means that portion of a system,used for one or more of the following: sample acquisition,sample transportation, sample conditioning, or protection of,the analyzer(s) from the effects of the stack effluent.,3.4.2 Organic analyzer means that portion of the,measurement system that senses the gas to be measured and,generates an output proportional to its concentration.,3.5 Response time means the time interval from a step,change in pollutant concentration at the inlet to the,emission measurement system to the time at which 95 percent,of the corresponding final value is reached as displayed on,the recorder.,1252,3.6 Span Value means the upper limit of a gas,concentration measurement range that is specified for,affected source categories in the applicable part of the,regulations. The span value is established in the,applicable regulation and is usually 1.5 to 2.5 times the,applicable emission limit. If no span value is provided,use a span value equivalent to 1.5 to 2.5 times the expected,concentration. For convenience, the span value should,correspond to 100 percent of the recorder scale.,3.7 Zero drift means the difference in the,measurement system response to a zero level calibration gas,before or after a stated period of operation during which no,unscheduled maintenance, repair, or adjustment took place.,4.0 Interferences. [Reserved],5.0 Safety.,5.1 Disclaimer. This method may involve hazardous,materials, operations, and equipment. This test method may,not address all of the safety problems associated with its,use. It is the responsibility of the user of this test,method to establish appropriate safety and health practices,and determine the applicability of regulatory limitations,prior to performing this test method. The analyzer users,manual should be consulted for specific precautions to be,taken with regard to the analytical procedure.,1253,5.2 Explosive Atmosphere. This method is often,applied in highly explosive areas. Caution and care should,be exercised in choice of equipment and installation.,6.0 Equipment and Supplies,6.1 Measurement System. Any measurement system for,total organic concentration that meets the specifications of,this method. A schematic of an acceptable measurement,system is shown in Figure 25A-1. All sampling components,leading to the analyzer shall be heated > 110EC (220EF),throughout the sampling period, unless safety reasons are,cited (Section 5.2) The essential components of the,measurement system are described below:,6.1.1 Organic Concentration Analyzer. A flame,ionization analyzer (FIA) capable of meeting or exceeding,the specifications of this method. The flame ionization,detector block shall be heated >120EC (250EF).,6.1.2 Sample Probe. Stainless steel, or equivalent,three-hole rake type. Sample holes shall be 4 mm (0.16-in.),in diameter or smaller and located at 16.7, 50, and 83.3,percent of the equivalent stack diameter. Alternatively, a,single opening probe may be used so that a gas sample is,collected from the centrally located 10 p……
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