ASTM_D_2186_-_84_1999e1.pdf

Designation:D 2186 84(Reapproved 1999)e1An American National StandardStandard Test Methods forDeposit-Forming Impurities in Steam1This standard is issued under the fixed designation D 2186;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.e1NOTEFootnotes were editorially removed in June 1999.1.Scope1.1 These test methods cover the determination of theamount of deposit-forming impurities in steam.Determinationsare made on condensed steam samples in all test methods.TestMethods A,B,and C give a measure of the amount of totaldeposit-forming material present;Test Method D deals withspecial constituents that may be present.Special precautionsand equipment,calculation procedures,and ranges of applica-bility are described.The following test methods are included:SectionsTest Method A(Gravimetric or Evaporative)6 to 12Test Method B(Electrical Conductivity)13 to 19Test Method C(Sodium Tracer)20 to 26Test Method D(Silica and Metals)27 to 301.2 Test Method A is applicable for determining totaldissolved and suspended solids in concentrations normally notless than 0.1 mg/L(ppm).It is applicable only to long-timesteady-state conditions and is not applicable for transients.1.3 Test Method B will measure minimum impurity concen-trations varying from 3 mg/L(ppm)down to at least 0.005mg/L(ppm),depending on the means for removing dissolvedgases from the steam condensate.The means for removingdissolved gases also affects the storage capacity of steamcondensate in the system and,thus,affects the response of thesystem to transients.1.4 Because of the high sensitivity of methods for measur-ing sodium in steam condensate,Test Method C provides themost sensitive measure of impurity content for samples inwhich sodium is an appreciable percentage of the impuritiespresent.Concentrations as low as 0.6 g/L(ppb)can bedetected by flame photometry and as low as 0.5 g/L(ppb)bysodium ion electrode.The apparatus can be designed with lowvolume,and,therefore,Test Method C is the most responsiveto transient conditions.1.5 Test Method D covers the determination of silica andmetals in steam,which are not included in Test Methods B andC and are not individually determined using Test Method A.1.6 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2.Referenced Documents2.1 ASTM Standards:D 512 Test Methods for Chloride Ion in Water2D 515 Test Methods for Phosphorus in Water2D 516 Test Method for Sulfate Ion in Water2D 857 Test Methods for Aluminum in Water2D 859 Test Method for Silica in Water2D 992 Test Method for Nitrate Ion in Water3D 1066 Practice for Sampling Steam2D 1068 Test Methods for Iron in Water2D 1125 Test Methods for Electrical Conductivity and Re-sistivity of Water2D 1129 Terminology Relating to Water2D 1339 Test Methods for Sulfite Ion in Water4D 1428 Test Methods for Sodium and Potassium in Waterand Water-Formed Deposits by Flame Photometry4D 1687 Test Methods for Chromium in Water2D 1688 Test Methods for Copper in Water2D 1886 Test Methods for Nickel in Water2D 1888 Test Methods for Particulate and Dissolved Matter,Solids,or Residue in Water2D 2791 Test Method for Continuous Determination of So-dium in Water2D 3082 Test Method for Boron in Water2D 3370 Practices for Sampling Water from Closed Con-duits21These test methods are under the jurisdiction of ASTM Committee D-19 onWater and are the direct responsibility of Subcommittee D19.03 on Sampling ofWater and Water-Formed Deposits,and Surveillance of Water.Current edition approved Oct.26,1984.Published January 1985.Originallypublished as D 2186 66.Last previous edition D 2186 79.2Annual Book of ASTM Standards,Vol 11.01.3DiscontinuedSee 1983 Annual Book of ASTM Standards,Vol 11.01.4DiscontinuedSee 1989 Annual Book of ASTM Standards,Vol 11.02.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.3.Terminology3.1 DefinitionsFor definitions of terms used in these testmethods,refer to Terminology D 1129.4.Significance and Use4.1 Limiting the concentration of deposit-forming impuri-ties in steam is of significance to protect both steam generatorsand steam turbines from damage or degradation of perfor-mance,or both.4.1.1 Steam entering superheaters and reheaters of steamgenerators always contains some impurities.If the concentra-tion of impurities is sufficiently low,the impurities are dis-solved in superheated steam and are carried out of the steamgenerator.However,if the steam contains a sufficient amountof any substance to exceed its solubility limit in steam,thesubstance is likely