ASTM_D_5503_-_94_2008.pdf

Designation:D550394(Reapproved 2008)Standard Practice forNatural Gas Sample-Handling and Conditioning Systems forPipeline Instrumentation1This standard is issued under the fixed designation D5503;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.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 practice covers sample-handling and conditioningsystems for typical pipeline monitoring instrumentation(gaschromatographs,moisture analyzers,and so forth).The selec-tion of the sample-handling and conditioning system dependsupon the operating conditions and stream composition.1.2 This practice is intended for single-phase mixtures thatvary in composition.A representative sample cannot be ob-tained from a two-phase stream.1.3 The values stated in SI units are to regarded as standard.The values stated in English units are for information only.1.4 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1142 Test Method for Water Vapor Content of GaseousFuels by Measurement of Dew-Point TemperatureD3764 Practice for Validation of the Performance of ProcessStream Analyzer Systems2.2 Other Standards:ANSI/API 2530(AGA Report Number 3)3AGA Report Number 84NACE Standard MR-01-7553.Terminology3.1 Definitions:3.1.1 compressed natural gasnatural gas compressed toapproximately 3600 psi.3.1.2 densitymass per unit volume of the substance beingconsidered.3.1.3 dew pointthe temperature and pressure at which thefirst droplet of liquid forms from a vapor.3.1.4 lag timetime required to transport the sample to theanalyzer.3.1.5 natural gasmixture of low molecular weight hydro-carbons obtained from petroleum-bearing regions.3.1.6 sample probedevice to extract a representativesample from the pipeline.3.1.7 system turnaround timethe time required to trans-port the sample to the analyzer and to measure the desiredcomponents.4.Significance and Use4.1 A well-designed sample-handling and conditioning sys-tem is essential to the accuracy and reliability of pipelineinstruments.Approximately 70%of the problems encounteredare associated with the sampling system.5.Selection of Sample-Handling and ConditioningSystem5.1 The sample-handling and conditioning system mustextract a representative sample from a flowing pipeline,trans-port the sample to the analyzer,condition the sample to becompatible with the analyzer,switch sample streams andcalibration gases,transport excess sample to recovery(ordisposal),and resist corrosion by the sample.5.2 The sample probe should be located in a flowingpipeline where the flow is fully developed(little turbulence)and where the composition is representative.In areas of highturbulence,the contaminates that normally flow along thebottom or the wall of the pipeline will form aerosols.5.3 The purpose of the sample probe is to extract a repre-sentative sample by obtaining it near the center of the pipelinewhere changes in stream composition can be quickly detected.1This practice is under the jurisdiction of ASTM Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.01 on Collection andMeasurement of Gaseous Samples.Current edition approved Dec.1,2008.Published July 2009.Originally approvedin 1994.Last previous edition approved in 2003 as D5503 94(2003).DOI:10.1520/D5503-94R08.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from American Gas Association,1515 Wilson Blvd.,Arlington,VA22209.5Available from NACE International(NACE),1440 South Creek Dr.,Houston,TX 77084-4906,http:/www.nace.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.3.1 The tip in the sample probe should be positioned in thecenter one third of the pipeline,away from the pipeline wallwhere large particles accumulate.5.3.2 The probe should be a minimum of five pipe diametersfrom any device that could produce aerosols or significantpressure drop.5.3.3 The sample probe should not be located within adefined meter tube region(see ANSI/API 2530 AGA ReportNumber 3 and AGA Report Number 8 for more information).5.3.4 The sample probe should be mounted vertically fromthe top on horizontal pipelines.The sample probe should not belocated on vertical pipelines.5.4 The sampling-handling system must tr