1、Designation:D627314Standard Test Methods forNatural Gas Odor Intensity1This standard is issued under the fixed designation D6273;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 indica
2、tes the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 These test methods cover the procedures for determin-ing the odor intensity of natural gas through the use ofinstruments that dilute and mix the sampled natural gas wi
3、thair.The mixed gas stream is then sniffed by the operator for thepurpose of determining the threshold detection level or thereadily detection level,or both,for odorant in the natural gasstream.1.2 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It
4、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:2D4150 Terminology Relating to Gaseous FuelsD5287 Practice for Automatic Sampling o
5、f Gaseous FuelsE253 Terminology Relating to Sensory Evaluation of Mate-rials and Products2.2 Other Standards49 CFR Part 192.625 Odorization of gas33.Terminology3.1 Definitions:3.1.1 odorant,nsulfur-bearing compound that gives natu-ral gas a distinctive odor.For the purpose of these test methods,natu
6、ral gas odorants may be compounds that are present at thewellhead or commercial mixtures that are added to the gasstream,or both.3.1.2 olfactory fatigue,ndesensitization of the sense ofsmell through either prolonged exposure or repeated exposureover a short period of time to an odor,a mixture of odo
7、rs,orseries of odors.3.1.3 sniff,vismell or snuff with short,audible inhalations.3.2 Definitions of Terms Specific to This Standard:3.2.1 high pressure,nfor the purpose of these testmethods,high pressure refers to natural gas pressure greaterthan the maximum inlet pressure specified by the manufactu
8、rerof the gas dilution apparatus.3.2.2 intensity,nthe magnitude of odor perceived by theoperator.3.2.3 low pressure,nfor the purpose of these test methods,low pressure refers to natural gas pressure less than or equal tothe maximum inlet pressure specified by the manufacturer ofthe gas dilution appa
9、ratus.3.2.4 operator(s),nthe person(s)performing the testingdescribed in these test methods.Because of the nature of thetesting described herein,the operator shall be qualified toperform this work(see 5.2).3.2.5 readily detectable level,nthe concentration of natu-ral gas and odorant mixture in air a
10、t which the operator is ableto detect and identify natural gas odor.3.2.6 threshold detection level,nthe concentration ofnatural gas and odorant mixture in air at which the operator isbarely able to detect an odor.3.3 For definitions of terms related to natural gas that areused in these test methods
11、,refer to Practice D5287.3.4 For definitions of terms related to olfactory testing thatare used in these test methods,refer to Terminology E253.4.Significance and Use4.1 Federal regulations(49 CFR Part 192.625)state:“Acombustible gas in a distribution line must contain a naturalodorant or be odorize
12、d so that at a concentration in air ofone-fifth of the lower explosive limit,the gas is readilydetectable by a person with a normal sense of smell.”Theseregulations state further that“To assure the proper concentra-tion of odorant with this section,each operator must conductperiodic sampling of comb
13、ustible gases using an instrumentcapable of determining the percentage of gas in air at which the1These test methods are under the jurisdiction of Committee D03 on GaseousFuels and is the direct responsibility of Subcommittee D03.05 on Determination ofSpecial Constituents of Gaseous Fuels.Current ed
14、ition approved Jan.1,2014.Published February 2014.Originallyapproved in 1998.Last previous edition approved in 2008 as D6273 08.DOI:10.1520/D6273-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards
15、volume information,refer to the standards Document Summary page onthe ASTM website.3Available from Standardization Documents Order Desk,DODSSP,Bldg.4,SectionD,700RobbinsAve.,Philadelphia,PA19111-5098,http:/www.dodssp.daps.mil.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Consho
16、hocken,PA 19428-2959.United States1 odor becomes readily detectable.”Additionally,a number ofstates have enacted legislation that requires natural gas to beodorized so that it is detectable at concentrations less than onefifth of the lower explosive limit.See Note 1.While regulationsdo not specify the exact method for determining compliance,ithas been documented that compliance testing must be olfactoryin nature.4NOTE1For example,Massachusetts Section 192.625 MFS Standardsrequires that“.a concen
