ASTM_D_3700_-_14.pdf

Designation:D370014Standard Practice forObtaining LPG Samples Using a Floating Piston Cylinder1This standard is issued under the fixed designation D3700;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.Scope*1.1 This practice covers the equipment and procedures forobtaining a representative sample of liquefied petroleum gas(LPG),such as specified in ASTM Specification D1835,GPA2140,and comparable international standards.It may also beused for other natural gas liquid(NGL)products that arenormally single phase(for example,NGL mix,field butane,and so forth),defined in other industry specifications orcontractual agreements,and for volatile(higher vapor pres-sure)crude oils.1.2 This practice is not intended for non-specification prod-ucts that contain significant quantities of undissolved gases(N2,CO2),free water or other separated phases,such as raw orunprocessed gas/liquids mixtures and related materials.Thesame equipment can be used for these purposes,but additionalprecautions are generally needed to obtain representativesamples of multi-phase products(see Appendix X1).1.3 This practice includes recommendations for the locationof a sample point in a line or vessel.It is the responsibility ofthe user to ensure that the sampling point is located so as toobtain a representative sample.1.4 The values stated in SI units are to be regarded asstandard.The values given in parentheses are for informationonly.1.5 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:2D1265 Practice for Sampling Liquefied Petroleum(LP)Gases,Manual MethodD1835 Specification for Liquefied Petroleum(LP)Gases2.2 GPA Standards:3GPA 2174 Obtaining Liquid Hydrocarbon Samples forAnalysis by Gas ChromatographyGPA 2140 Liquefied Petroleum Gas Specifications and TestMethods3.Terminology3.1 Definitions:3.1.1 floating piston cylinder(FPC),na high pressuresample container,with a free floating internal piston thateffectively divides the container into two separate compart-ments.3.1.1.1 DiscussionA floating piston cylinder is used tocollect a sample of liquid under pressure without the formationof a gaseous phase which can result in changes in thecomposition of the liquid sample.3.1.2 maximum fill volume(reduced fill volume),nthevolume of a container occupied by the sample,usually ex-pressed as a percentage of the total capacity.3.1.2.1 DiscussionSome regulatory agencies use the ex-pressions“maximum fill density”and“reduced fill density.”4.Summary of Practice4.1 A liquid petroleum gas(LPG)sample is transferred as aliquid under pressure from a sample point to a floating pistoncylinder.The floating piston cylinder(FPC)is designed tocollect liquid samples with no vaporization by displacing apiston against a pressurizing fluid(preferably an inert gas).Thepiston serves as a physical barrier between the sample and thepressurizing fluid,at the sampling pressure.The position of thepiston at the end of sampling indicates the percent fill of thesample cylinder.4.2 It is the responsibility of the user of this practice tolocate the sample point at a suitable location and orientationwhere the product being sampled is a representative,singlephase,homogeneous liquid.1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts,Liquid Fuels,and Lubricants and is the direct responsibility of Subcom-mittee D02.H0 on Liquefied Petroleum Gas.Current edition approved May 1,2014.Published May 2014.Originallyapproved in 1978.Last previous edition approved in 2012 as D3700 12.DOI:10.1520/D3700-14.2For 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 Gas Processors Association(GPA),6526 E.60th St.,Tulsa,OK74145,www.gpaglobal.org*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Significance and Use5.1 This practice allows the collection of a representativesample of LPG that may contain trace volatile dissolvedcomponents such as methane,ethane,and nitrogen.Samplingby Practice D1265 can result in a small,but predictable,loss ofthese lighter components.Practice D1265 is suitable forcollecting samples for routine specification testing,as the smallloss of light components is not significant under SpecificationD1835 specification requirements.