1、Designation:D498420Standard Test Method forCarbon Dioxide in Natural Gas Using Length-of-StainDetector Tubes1This standard is issued under the fixed designation D4984;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last r
2、evision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers a rapid and simple field deter-mination of carbon dioxide in natural gas pipelines.Availabledetector tube
3、s provide a total measuring range of 100 ppm(parts per million)up to 60%by volume,although the majorityof applications will be on the lower end of this range(that is,under 5%).At least one manufacturer provides a special kit formeasurements from 10 to 100%CO2,but the normal 100 cchand pump is not us
4、ed.See Note 1.NOTE1High-range carbon dioxide detector tubes will have measuringranges in percent(%)CO2,and low-range tubes will be in parts permillion(ppm).To convert percent to ppm,multiply by 10 000(1%=10 000 ppm).1.2 UnitsThe values stated in SI units are regarded asstandard.The inch-pound units
5、in parentheses are for informa-tion only.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of
6、 regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Tra
7、de Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D4150 Terminology Relating to Gaseous Fuels2.2 GPA Standard:32337 Test for Hydrogen Sulfide and Carbon Dioxide inNatural Gas Using Length-of-Stain Tubes3.Terminology3.1 DefinitionsFor definitions of ge
8、neral terms used inD03 Gaseous Fuels standards,refer to Terminology D4150.3.2 Definitions of Terms Specific to This Standard:3.2.1 detector tube pump,na hand-operated pump of apiston or bellows type.3.2.1.1 DiscussionIt must be capable of drawing 100 mLper stroke of sample through the detector tube
9、with a volumetolerance of 65 mL.4It must be specifically designed for usewith detector tubes.3.2.1.2 DiscussionA detector tube and pump togetherform a unit and must be used as such.Each manufacturercalibrates detector tubes to match the flow characteristics oftheir specific pump.Crossing brands of p
10、umps and tubes is notpermitted,as considerable loss of system accuracy is likely tooccur.43.2.2 gas sampling chamber,nany container that providesfor access of the detector tube into a uniform flow of samplegas at atmospheric pressure and isolates the sample from thesurrounding atmosphere.3.2.2.1 Dis
11、cussionA stainless steel needle valve(or pres-sure regulator)is placed between the source valve and thesampling chamber for the purpose of throttling the sampleflow.Flow rate should approximate 1 to 2 volume changes perminute or,at minimum,provide exit gas flow throughout thedetector tube-sampling p
12、eriod.3.2.2.2 DiscussionA suitable sampling chamber may bedevised from a polyethylene wash bottle of nominal 500 mL(16 oz)or 1 L(32 oz)size.The wash bottles internal deliverytube provides for delivery of sample gas to the bottom of thebottle.A 14.7 mm(12in.)hole cut in the bottles cap providesaccess
13、 for the detector tube and vent for the purge gas(see Fig.1).(An alternate flow-through sampler may be fashioned using1This test method is under the jurisdiction ofASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.07 on Analysis ofChemical Composition of Gaseous
14、 Fuels.Current edition approved Dec.15,2020.Published January 2021.Originallyapproved in 1989.Last previous edition approved in 2015 as D4984 06(2015).DOI:10.1520/D4984-20.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual
15、 Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Gas Processors Association(GPA),6060 American Plaza,Suite700,Tulsa,OK 74135,http:/www.gpaglobal.org.4Direct Reading Colorimetric Indicator Tubes Manual,Second Edition,Ameri-can I
16、ndustrial Hygiene Association,Publication No.172-SI-93,1993.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.a 1 gal(3.8 L)“zip
