ASTM_D_168_-_94_2000.pdf

Designation:D 168 94(Reapproved 2000)American Association StateHighway Transportation StandardAASHTO No.61Standard Test Method forCoke Residue of Creosote1This standard is issued under the fixed designation D 168;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the cokeresidue(fixed carbon)of creosote,coal tar,and creosote-coaltar solutions.As coal tars vary in their coke residue values,themethod is therefore not a quantitative index of the percentageof coal tar in creosote-coal tar solutions.However,by speci-fying maximum amounts of coke residue as done in AWPAStandards P 2 and P 12,the method does serve to limit theamount of coal tar in such solutions;and by specifying aminimum as in Standard P 12 it ensures the presence of somecoal tar.Formerly the test was also used as a check on thecleanliness of AWPA P1 creosote(absence of coal tar).1.1.1 Test Methods D 38 covers the sampling of woodpreservatives prior to testing.1.2 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.See Section 6 forspecific precautionary statements.2.Referenced Documents2.1 ASTM Standards:D 38 Test Methods for Sampling Wood Preservatives Priorto Testing2D 246 Test Method for Distillation of Creosote andCreosote-Coal Tar Solutions22.2AWPA Standards:P 2 CreosoteCoal Tar Solution3P 12 CreosoteCoal Tar Solution for Treating of Marine(Coastal Waters),Piles,and Timbers33.Summary of Test Method3.1 After subjecting the creosote-coal tar solution(oil)under test to the distillation method(Standard A1,Section 2),the weighed residue at 355C in the distillation flask isthoroughly mixed and a one-gram sample transferred to aspecial platinum crucible with vented cover.The crucible isthen placed in a furnace maintained at 950 6 20C for exactly7 min.A final weighing gives the amount of coke of thedistillation residue.The coke residue of the creosote-coal tarsolution under test is calculated from(a)the percentage ofdistillation residue at 355C,(b)the weight of the sample ofdistillation residue transferred to the platinum crucible,and(c)the weight of coke remaining in the platinum crucible after thecoking operation.4.Significance and Use4.1 This test method is useful as an indicator of thepreparation of coal tar in solution with coal tar distillate.Thetest method can also be used as one element in establishinguniformity of shipments and sources of supply.5.Apparatus5.1 Crucible and CoverPlatinum crucible and cover withdimensions as shown in Fig.1.The cover shall be tightlyfitting,shall have a depth of between 10.0 and 10.2 mm,andshall have a hole 2.0 mm in diameter at its center.The cruciblewithout cover shall have a capacity of 25 to 30 mL.It shallhave an outside diameter at the top of 34 to 35 mm,and outsidediameter at the bottom of 19 to 21 mm,and a height of 40 to45 mm.The weight of crucible with cover shall be 25 to 35 g.5.2 Crucible HolderThe crucible holder shall be madefrom No.20 Nichrome wire and a brass ring as shown in Fig.2.The holder serves as a support for the platinum crucibleduring the coking operation.1This test method is under the jurisdiction of ASTM Committee D-7 on Woodand is the direct responsibility of Subcommittee D07.06 on Treatments for WoodProducts.This test method is identical in substance with the Standard Method for theDetermination of Coke Residue which is part of the American Wood-PreserversAssociation Standard Methods for Analysis of Creosote and Oil-Type Preservatives(A1-78).Acknowledgment is made to the American Wood-Preservers Associationfor its development of the subject matter covered in this standard.Current edition approved July 15,1994.Published September 1994.Originallypublished as D 168 23 T.Last previous edition D 168 86.2Annual Book of ASTM Standards,Vol 04.10.3Available from the American Wood-Preservers Assn.,P.O.Box 286,Wood-stock,MD 21163-0286.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.5.3 FurnaceA vertical electric tube furnace4having aheating chamber 112in.(38 mm)in diameter,by 6 in.(150mm)in depth.The power input shall be 300 to 400 W at 115V.The furnace shall be equipped with a suitable rheostat orvariable transformer and pyrometer,for control at 950 6 20C.A thermocouple shall be installed through a central hole in thebottom of the furnace,and sealed in place so that its junctionis located 2 to 5 mm below the eventual position of the bottomof the platinum crucible.5.4 Gas BurnerAgas burner of the bunsen or Meker type