ASTM_D_1247_-_54_1975_scan.pdf

Designation:D 1247-54(Reapproved 1975)Standard Method of Amertr;.n Ntcional S!andltd1.77 7-1973 IR-1963)AIPloved March 21.1973 By Ame11con N 11 onll Sundrds lns1u1e SAMPLING MANUFACTURED GAS1 This Standard is issued under the ficd designation 0 1247:the number imcdiately folov.ing the designation.indicates the year of original adoption or,in the case of revision.the year of last n:,u,on.A number tn parentheses tndtcates the year of last reapproval.I.Scope 1.1 This method covers the procedures for securing representative samples of manufac-tured gas,and correlates the size or type of sample with the analysis to be done subse-quently on that sample.NOTE-The values stated in U.S.customary units arc 10 be regarded as the standard.l.General Considerations 2.1 In collecting samples of manufactured gas,consideration must be given to the pur-poses for which the samples are to be used and the conditions under which they must be secured.Consideration must also be given to the volume of sample required for the purpose intended.to the size and length of the sam-pling line,and to the size and design of con tainers.Account must be taken of the possible constituents in the gas with reference to any action upon the material of which the lines,containers,and auxiliary equipment are con structed.The procedure used should be ca-pable of giving results that can be duplicated.Unless a representative sample has been ob-tained,the results of any subsequent analyt-ical test.regardless of the accuracy of the test itself,will be erroneous and misleading.3.Volume of Sample Required 3.1 The volume of sample collected is gov-erned by the test to be made and the method to be used.The following volumes are min-imum amounts sufficient for two determina-tions and necessary purging:Chemical a analysis Fractionatton ttas analysis Specific gravit)Heating value(Btu)IOOOcm 5 to 10ft(0.141 to 0.283 m)I ft(0.028 ml 3 to 5 ft(0.085 Total sulfur by Referees apparatus Determination of ammonia Determination of naphthalene Hydrotten sulridc by Tutwetler method Hydroen nlly Is-sued 1952.Replaces D 1247 S2 T.NOTICE:This standard has either been superseded and replaced by a new version or discontinued.Contact ASTM International(www.astm.org)for the latest information.conducting a stream of ga from the ampling ource into a purged container,and th u se-curing a representative sample.Snap amples may suffice,or a serits of consecutive snap Stmples may be considered a an.1vcr.1ge ample.Average:samples may alo be ob-t.Jined by continuous sampling into a portable container or direct to a recording or indi-cating instrument over a predetermined period of time.5.2 Purging may be accomplihed by means of the gas to he sampled,c1ther by dls-placecnt of air or by water displacement;or by the utilization of u vacuum.5.3 Manufactured gas will usually be under uflic1ent pressure to purge and fill the o;ample container;otherwise auxiliary mechanical equipment must be employed(see 6.1.4).5.4 The choice of the type of sample(snap or continuous),the method of purg-ing the kind of container.and the selection of auxiliary prcssure equtpment,will be deter-mined by the analyses to be donc on the sam-ple,by the composition of the gas to be sam-pled,and hy the available equtpmenl.6.Apparatus 6.1 The sampling equipment should guard against contamination by air,leakage,and losses by absorption or chemical react1on.The use of rubber should be kept to a mmimum,and any rubber used should be of a grade that will not react with the sample and that will have low permeability characteristics.Plastic tubing may be as satisfactory where flc:llibility is imperative.Rubber hose should not be used where high pressures are involved.6.1.1 Sampling Probes of metal are prefer-able because of their durability.I ron pipe,1f or 114 in.in diameter,threaded or welded to the main or othc:r source of sample and ex-tending some distance into the vessel,makes a satisfactory connection.Condensate on the inside surface of the main will be avoided,and the point of average velocity of the gas,one sixth of the diameter of the main,can be reached at the same time.Figure I shows a simple open-end sampling tube.If unusually high temperatures are encountered,water-cooled probes(Fig.2)may be required.6.1.2 Sampling Lines-I ron pipe 1f or I in.in diameter,and copper.Monel metal,or 84 0 1247 hr.tss tubing S:to l!.in.(2.4 to 9.5 mm)in outside diameter,ure recommended us sam piing lines.Where sulfur compounds are to be determined,glas or quartz tubing should be ucd for the low pressures and aluminum when higher pressures are met.Any sumpling line should be as short and of as small a di amcter as practicable to decrease purging time,particularly in the case of a continuous sampling line direct from the source of supply to analytical apparatus in order that the test in.,trumcnt may follow closely any change in composition of the supply.6.1.3 Sample Containers may vary in size from 125 cma to several cubic feet.The design