EPA Method 21 Determination Of Volatile Organic Compound Leaks
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ID： |
5308EDC51A7B41B1B94FFE9BADCF47C4 |
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文件大小(MB)： |
0.03 |
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页数： |
16 |
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文件格式： |
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日期： |
2011-5-20 |
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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）：
1151,METHOD 21 - DETERMINATION OF VOLATILE,ORGANIC COMPOUND LEAKS,1.0 Scope and Application.,1.1 Analytes.,Analyte CAS No.,Volatile Organic Compounds,(VOC),No CAS number assigned,1.2 Scope. This method is applicable for the,determination of VOC leaks from process equipment. These,sources include, but are not limited to, valves, flanges and,other connections, pumps and compressors, pressure relief,devices, process drains, open-ended valves, pump and,compressor seal system degassing vents, accumulator vessel,vents, agitator seals, and access door seals.,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 portable instrument is used to detect VOC leaks,from individual sources. The instrument detector type is,not specified, but it must meet the specifications and,performance criteria contained in Section 6.0. A leak,definition concentration based on a reference compound is,specified in each applicable regulation. This method is,intended to locate and classify leaks only, and is not to be,1152,used as a direct measure of mass emission rate from,individual sources.,3.0 Definitions.,3.1 Calibration gas means the VOC compound used to,adjust the instrument meter reading to a known value. The,calibration gas is usually the reference compound at a known,concentration approximately equal to the leak definition,concentration.,3.2 Calibration precision means the degree of,agreement between measurements of the same known value,expressed as the relative percentage of the average,difference between the meter readings and the known,concentration to the known concentration.,3.3 Leak definition concentration means the local VOC,concentration at the surface of a leak source that indicates,that a VOC emission (leak) is present. The leak definition,is an instrument meter reading based on a reference,compound.,3.4 No detectable emission means a local VOC,concentration at the surface of a leak source, adjusted for,local VOC ambient concentration, that is less than 2.5,percent of the specified leak definition concentration. that,indicates that a VOC emission (leak) is not present.,1153,3.5 Reference compound means the VOC species selected,as the instrument calibration basis for specification of the,leak definition concentration. (For example, if a leak,definition concentration is 10,000 ppm as methane, then any,source emission that results in a local concentration that,yields a meter reading of 10,000 on an instrument meter,calibrated with methane would be classified as a leak. In,this example, the leak definition concentration is 10,000,ppm and the reference compound is methane.),3.6 Response factor means the ratio of the known,concentration of a VOC compound to the observed meter,reading when measured using an instrument calibrated with,the reference compound specified in the applicable,regulation.,3.7 Response time means the time interval from a step,change in VOC concentration at the input of the sampling,system to the time at which 90 percent of the corresponding,final value is reached as displayed on the instrument,readout meter.,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,1154,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.,5.2 Hazardous Pollutants. Several of the compounds,leaks of which may be determined by this method, may be,irritating or corrosive to tissues (e.g., heptane) or may be,toxic (e.g., benzene, methyl alcohol). Nearly all are fire,hazards. Compounds in emissions should be determined,through familiarity with the source. Appropriate,precautions can be found in reference documents, such as,reference No. 4 in Section 16.0.,6.0 Equipment and Supplies.,A VOC monitoring instrument meeting the following,specifications is required:,6.1 The VOC instrument detector shall respond to the,compounds being processed. Detector types that may meet,this requirement include, but are not limited to, catalytic,oxidation, flame ionization, infrared absorption, and,photoionization.,6.2 The instrument shall be capable of measuring the,leak definition concentration specified in the regulation.,1155,6.3 The scale of the instrument meter shall be,readable to ±2.5 percent of the specified leak definition,concentration.,6.4 The instrument shall be equi……
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