1、Designation: D 887 08Standard Practices forSampling Water-Formed Deposits1This standard is issued under the fixed designation D 887; 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
2、 indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These practices cover the sampling of water-formeddeposits for chemical, physical, biological, or radiologicalanalysis. The practices cover both field and
3、laboratory sam-pling. It also defines the various types of deposits. Thefollowing practices are included:SectionsPractice ASampling Water-Formed Deposits From Tubingof Steam Generators and Heat Exchangers8to10Practice BSampling Water-Formed Deposits From SteamTurbines11 to 141.2 The general procedur
4、es of selection and removal ofdeposits given here can be applied to a variety of surfaces thatare subject to water-formed deposits. However, the investigatormust resort to his individual experience and judgment inapplying these procedures to his specific problem.1.3 The values stated in inch-pound u
5、nits are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is therespons
6、ibility 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 7, 9.8,9.8.4.6, and 9.14 for specific hazards statements.2. Referenced Documents2.1 ASTM Standards:2D 512 Test Methods for C
7、hloride Ion In WaterD 934 Practices for Identification of Crystalline Com-pounds in Water-Formed Deposits By X-Ray DiffractionD 1129 Terminology Relating to WaterD 1193 Specification for Reagent WaterD 1245 Practice for Examination of Water-Formed Depositsby Chemical MicroscopyD 1293 Test Methods fo
8、r pH of WaterD 2331 Practices for Preparation and Preliminary Testing ofWater-Formed DepositsD 2332 Practice for Analysis of Water-Formed Deposits byWavelength-Dispersive X-Ray FluorescenceD 3483 Test Methods for Accumulated Deposition in aSteam Generator TubeD 4412 Test Methods for Sulfate-Reducing
9、 Bacteria inWater and Water-Formed Deposits3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 biological depositswater-formed deposits of organ-isms or the products of their life processes.3.1.1.1 The biological deposits may be composed of micro-scopic organisms, as in slimes, or
10、 of macroscopic types such asbarnacles or mussels. Slimes are usually composed of depositsof a gelatinous or filamentous nature.3.1.2 corrosion productsa result of chemical or electro-chemical reaction between a metal and its environment.3.1.2.1 A corrosion deposit resulting from the action ofwater,
11、 such as rust, usually consists of insoluble materialdeposited on or near the corroded area; corrosion productsmay, however, be deposited a considerable distance from thepoint at which the metal is undergoing attack.3.1.3 scalea deposit formed from solution directly inplace upon a surface.3.1.3.1 Sc
12、ale is a deposit that usually will retain its physicalshape when mechanical means are used to remove it from thesurface on which it is deposited. Scale, which may or may notadhere to the underlying surface, is usually crystalline anddense, frequently laminated, and occasionally columnar instructure.
13、3.1.4 sludgea water-formed sedimentary deposit.1These practices are under the jurisdiction of ASTM Committee D19 on Waterand are the direct responsibility of Subcommittee D19.03 on Sampling Water andWater-Formed Deposits, Analysis of Water for Power Generation and Process Use,On-Line Water Analysis,
14、 and Surveillance of Water.Current edition approved May 1, 2008. Published May 2008. Originallyapproved in 1946. Last previous edition approved in 2003 as D 887 82 (2003)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
15、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4.1 The water-formed sedimentary deposits may includeall suspended so
16、lids carried by the water and trace elementswhich were in solution in the water. Sludge usually does notcohere sufficiently to retain its physical shape when mechanicalmeans are used to remove it from the surface on which itdeposits, but it may be baked in place and be hard andadherent.3.1.5 water-f
17、ormed depositsany accumulation of in-soluble material derived from water or formed by the reactionof water upon surfaces in contact with the water.3.1.5.1 Deposits formed from or by water in all its phasesmay be further classified as scale, sludge, corrosion products,or biological deposit. The overa
18、ll composition of a deposit orsome part of a deposit may be determined by chemical orspectrographic analysis; the constituents actually present aschemical substances may be identified by microscope or x-raydiffraction studies. Organisms may be identified by micro-scopic or biological methods.3.2 Def
19、initionsFor definitions of other terms used in thesepractices, refer to Definitions D 1129.4. Summary of Practices4.1 These practices describe the procedures to be used forsampling water-formed deposits in both the field and labora-tory from boiler tubes and turbine components. They giveguidelines o
20、n selecting tube and deposit samples for removaland specify the procedures for removing, handling, and ship-ping of samples.5. Significance and Use5.1 The goal of sampling is to obtain for analysis a portionof the whole that is representative. The most critical factors arethe selection of sampling a
21、reas and number of samples, themethod used for sampling, and the maintenance of the integrityof the sample prior to analysis. Analysis of water-formeddeposits should give valuable information concerning cyclesystem chemistry, component corrosion, erosion, the failuremechanism, the need for chemical
22、cleaning, the method ofchemical cleaning, localized cycle corrosion, boiler carryover,flow patterns in a turbine, and the rate of radiation build-up.Some sources of water-formed deposits are cycle corrosionproducts, make-up water contaminants, and condenser coolingwater contaminants.6. Reagents and
23、Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all cases. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other g
24、rades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of analysis.6.1.1 Purity of WaterReferences to water shall be under-stood to mean water that meets or exceeds the quantitativespecifications for Type III
25、reagent water conforming to Speci-fication D 1193, Section 1.1.6.2 Materials:6.2.1 The highest purity material available should be usedfor removing the deposit samples.6.2.2 Filter Paper may contain water leachable contami-nants (chloride, fluoride, and sulfur) which can be removed bypretreatment pr
26、ior to sampling.6.2.3 Polyester Tape may contain impurities of antimonyand cadmium which must be considered during analysis.7. Hazards7.1 Warnings:7.1.1 Special safety precautions are necessary in usingacetone on a wipe material for removing water-formed deposits(see 9.8.4.6).7.1.2 Special handling
27、precautions may be required forworking with water-formed deposits containing radioactivenuclides (see 9.14).7.2 Cautions:7.2.1 Extreme care must be taken not to damage theunderlying surface when removing water-formed depositsamples from equipment in the field (see 9.8).7.2.2 The selection of samples
28、 necessarily depends on theexperience and judgment of the investigator. The intended useof the sample, the accessibility and type of the deposit, and theproblem to be solved will influence the selection of the samplesand the sampling method.7.2.3 The most desirable amount of deposit to be submitteda
29、s a sample is not specific. The amount of deposit should beconsistent with the type of analysis to be performed.7.2.4 The samples must be collected, packed, shipped, andmanipulated prior to analysis in a manner that safeguardsagainst change in the particular constituents or properties to beexamined.
30、7.2.5 The selection of sampling areas and number ofsamples is best guided by a thorough investigation of theproblem. Very often the removal of a number of samples willresult in more informative analytical data than would beobtained from one composite sample representing the entiremass of deposit. A
31、typical example is the sampling of depositsfrom a steam turbine. Conversely, in the case of a tube failurein a steam generator, a single sample from the affected areamay suffice.7.2.6 Most deposits are sampled at least twice before beingsubmitted to chemical or physical tests. The gross sample isfir
32、st collected from its point of formation in the field and thenthis sample is prepared for final examination in the laboratory.7.2.7 A representative sample is not an absolute prerequi-site. The quantity of deposit that can be removed is oftenlimited. In such cases, it is better to submit a single mi
33、xedsample (composite) and to describe how the sample wasobtained. For radiological analysis all samples should bechecked for activity levels before preparing a composite sincewide variations in radioactive content may occur in samples ofsimilar appearance and chemical composition.3Reagent Chemicals,
34、 American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Form
35、ulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D8870827.2.8 It is good practice for deposits to be taken andanalyzed every time a turbine is opened for repairs or inspec-tion. Deposit history can then supplement chemical records ofa unit, and deposit chemistry of units with and wit
36、houtcorrosion and other problems can be compared. Enoughinformation on deposits has been published (1,2)4that acomparison between different types of boilers and differentwater treatments, as well as an assessment of deposit corro-siveness, are possible. It has been a general experience thatabout 0.2
37、 % of a corrosive impurity, such as chloride, in adeposit, is a division between corrosive and noncorrosivedeposits.7.2.9 Deposits taken after a turbine is open do not exactlyrepresent chemical composition of deposits in an operatingturbine. Chemical thermodynamic data on steam additives andimpuriti
38、es, such as vapor pressures of solutions, ionization, andvolatility data are needed to reconstruct chemistry of environ-ment during operation.7.2.10 Typical changes which occur after the hot turbine isshut down and air is admitted are: (1) reactions with oxygenand carbon dioxide, (2) drying of some
39、deposits and waterabsorption by others, (3) leaching and recrystallization wheremoisture is allowed to condense, and (4) formation of ironhydroxide and hematite.PRACTICE ASAMPLING WATER-FORMEDDEPOSITS FROM TUBING OF STEAMGENERATORS AND HEAT EXCHANGERS8. Scope8.1 This practice covers the sampling of
40、water-formeddeposits from tubing of steam generators and heat exchangers.It covers both field and laboratory sampling of water-formeddeposits. It gives guidelines on selecting tube samples forremoval and specifies the procedure for removing tube samplesfrom the unit.9. Field Sampling9.1 Selection of
41、 Tube SamplesWhenever feasible, removethe tube containing the water-formed deposit. The length oftubing removed depends on the amount of deposits present andthe type of analyses to be performed. As a guideline, 3 ft (0.9m) of tubing is suggested. Table 1 contains a summary of thevarious procedures f
42、or selection of samples in the order ofpreference.9.1.1 Preferred Selection ProcedureSelect one or moreseparate tube samples containing the area of failure, heaviestdeposition, or principle concern (primary area) and include anyadjacent or closely related areas of these tube samples thatmight contai
43、n deposits significantly different from the primaryarea. Also, one or more tube samples is selected from adjacentrows or other related areas that might contain deposits signifi-cantly different from the primary area.9.1.2 Alternative Selection Procedure 1Select one ormore separate tube samples conta
44、ining the area of failure,heaviest deposition, or principle concern (primary area) andinclude any adjacent or closely related areas of these tubesamples that might contain deposits significantly different fromthe primary area. Use this procedure when it is impractical toremove the samples from adjac
45、ent rows or other related areasor when it is improbable that the information gained by suchsampling will justify the additional work involved.9.1.3 Alternative Selection Procedure 2Select one ormore separate tube samples containing the area of failure,heaviest deposition, or principle concern (prima
46、ry area). Usethis procedure when only the tube section containing theprimary area can be removed or when it is impractical toremove adjacent or closely related areas, or tube samples fromadjacent rows or other related areas, or when it is improbablethat the information gained by such sampling will j
47、ustify theadditional work involved.9.1.4 Alternative Selection Procedure 3Select one ormore tube samples containing an area adjacent or closelyrelated to the primary area. Use this procedure only when it isnot possible to obtain a tube section containing the primaryarea.9.1.5 Alternative Selection P
48、rocedure 4Select one ormore separate tube samples from adjacent rows or other relatedareas. Use this procedure only when it is not possible toremove a tube section from the primary area, adjacent to theprimary area, or closely related to the primary area.9.2 Taking the Tube SampleMark the tube that
49、is to beremoved (sampled) with a crayon. A long arrow can be used toshow: (1) the ligament that is facing into the furnace, and (2)which end of the tube is up. Mark the tube before it is removed.The marking should not involve the use of a hammer and dieor paint.9.2.1 Whenever possible, remove the tube samples bysawing. The tube should be dry-cut (no oil). Grinding wheelsand cutting torches can be used to obtain tube samples whichcannot be sawed. Grinding wheels and cutting torches canproduce sufficient heat to alter the composition of the depositnear the cutting poin
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