1、Designation: D 3864 06Standard Guide forContinual On-Line Monitoring Systems for Water Analysis1This standard is issued under the fixed designation D 3864; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、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 guide covers the selection, establishment, applica-tion, and validation and verification of monitoring systems fordetermining w
3、ater characteristics by continual sampling, auto-matic analysis, and recording or otherwise signaling of outputdata. The system chosen will depend on the purpose for whichit is intended: whether it is for regulatory compliance, processmonitoring, or to alert the user of adverse trends. If it is to b
4、eused for regulatory compliance, the method published orreferenced in the regulations should be used in conjunctionwith this guide and other ASTM methods.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 t
5、his standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 7.2. Referenced Documents2.1 ASTM Standards:2D 1129 Terminology Relating to WaterD 1193 Specification for Reagent
6、 WaterD 3370 Practices for Sampling Water from Closed ConduitsD 4210 Practice for Intralaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data3D 5540 Practice for Flow Control and Temperature Controlfor On-Line Water Sampling and AnalysisE 178 Practice for Dealing With Ou
7、tlying Observations2.2 ASTM Special Technical Publication:STP 442 Manual on Water43. Terminology3.1 DefinitionsFor definitions of terms used in this guiderefer to Terminology D 1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 Calibrations:3.2.1.1 laboratory check sample for flow-through
8、 systemscalibration curve calculated from withdrawn samples or addi-tional standards that may be spiked or diluted and analyzedusing the appropriate laboratory analyzer.3.2.1.2 line sample calibrationcoincidental comparisonof a line sample and adjustment of a continuous analyzer to thecompared labor
9、atory analyzer or a second continuous analyzer.3.2.1.3 multiple standard calibrationwhere the calibra-tion curve is calculated from a series of calibration standardscovering the range of the measurements of the sample beinganalyzed.3.2.1.4 probe calibrationwhere the probe is removedfrom the sample s
10、tream and exposed to a calibration solutionand the analyzer is adjusted to indicate the appropriate value.Alternately, two probes are exposed to the same solution andthe on-line analyzer is adjusted to coincide with the pre-calibrated laboratory instrument.3.2.1.5 reference sample calibrationcoincid
11、ental com-parison of a reference sample and adjustment of a continuousanalyzer to the compared laboratory analyzer results.3.2.2 cycle timethe interval between repetitive sampleintroductions in a monitoring system with discrete sampling.3.2.3 driftthe change in system output, with constantinput over
12、 a stated time period of unadjusted, continuousoperation; usually expressed as percentage of full scale over a24-h period.3.2.3.1 span driftdrift when the input is at a constant,stated upscale value.3.2.3.2 zero driftdrift when the input is at zero.3.2.4 full scalethe maximum measuring limit of thes
13、ystem for a given range.3.2.5 inputthe value of the parameter being measured atthe inlet to the analyzer.3.2.6 interferencean undesired output caused by a sub-stance or substances other than the one being measured. Theeffect of interfering substance(s) on the measured parameter ofinterest shall be e
14、xpressed as a percentage change (6)inthe1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.03 on Sampling of Water andWater-Formed Deposits, Surveillance of Water, and Flow Measurement of Water.Current edition approved July 1, 200
15、6. Published July 2006. Originally approvedin 1979. Last previous edition approved in 2000 as D 3864 96 (2000).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the s
16、tandards Document Summary page onthe ASTM website.3Withdrawn.4Available from ASTM Headquarters. Contact Customer Service, 100 BarrHarbor Drive, West Conshohocken, PA 19428-2959.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.measured
17、 component as the interference varies from 0 to100 % of the measuring scale. If the interference is nonlinear,an algebraic expression should be developed (or curve plotted)to show the varying effect.3.2.7 laboratory analyzera device that measures thechemical composition or a specific physical, chemi
18、cal, orbiological property of a sample.3.2.8 limit of detectiona concentration of twice the crite-rion of detection when it has been decided that the risk ofmaking a Type II error is equal to a Type I error as describedin Practice D 4210.3.2.9 linearitythe extent to which an actual analyzerreading a
19、grees with the reading predicted by a straight linedrawn between upper and lower calibration pointsgenerallyzero and full-scale. (The maximum deviation from linearity isfrequently expressed as a percentage of full-scale.)3.2.10 monitoring systemthe integrated equipment pack-age comprising sampling s
20、ystem, analyzer, and data outputequipment, required to perform water quality analysis auto-matically.3.2.10.1 analyzera device that continually measures thespecific physical, chemical, or biological property of a sample.3.2.10.2 data acquisition equipmentanalog or digital de-vices for acquiring, pro
21、cessing, or recording, or a combinationthereof, the output signals from the analyzer.3.2.10.3 sampling systemequipment necessary to delivera continual representative sample to the analyzer.3.2.11 outputa signal, usually electrical, that is related tothe parametric measurement and is the intended inp
22、ut to dataacquisition equipment.3.2.12 rangethe region defined by the minimum andmaximum measurable limits.3.2.13 repeatabilitya measure of the precision of oneanalyzer to repeat its results on independent introduction of thesame sample at different time intervals.3.2.14 reproducibilitya measure of
23、the precision of differ-ent analyzers to repeat results on the same sample.3.2.15 response timethe time interval from a step changein the input or output reading to 90 % of the ultimate reading.3.2.15.1 lag timethe time interval from a step change ininput to the first corresponding change in output.
24、3.2.15.2 total timethe time interval from a step change inthe input to a constant analyzer signal output.3.2.16 sample portthat point in the sampling systemlocated between the sample conditioning unit and the analyzeror at the outlet of the analyzer from which samples forlaboratory analysis are take
25、n.3.2.17 samples:3.2.17.1 line samplea process sample withdrawn from thesample port (3.2.16) during a period when the process streamflowing through the continuous analyzer is of uniform qualityand the analyzer result displayed is essentially constant.Laboratory tests or results from a second continu
26、ous analyzerare obtained from each sample and compared with the con-tinuous analyzer results obtained at the time of sampling.3.2.17.2 reference samplecan be a primary standard or adilution of a primary standard of known reference value. Thereference value must be established through multiple testin
27、gusing an appropriate ASTM or other standard laboratory testmethod. Bulk quantities of the reference sample must be storedand handled to avoid contamination or degradation. One ormore reference samples encompassing the range of the ana-lyzer may be required.NOTE 1It is essential that the laboratory
28、analyzer be checked care-fully before these tests are performed to ensure compliance with therequirements of the standard test procedure. To further ensure properoperation it is recommended that a previously calibrated reference sampleor an in-house control standard of known concentration be tested
29、tovalidate the operations of the laboratory analyzer.3.2.18 validationsa one-time comprehensive examinationof analytical results.3.2.18.1 reference sample validationsa reference sampleis analyzed a minimum of seven times by an appropriatecontinuous analyzer and by an appropriate laboratory analyzer.
30、A comparison is made between the average continuous ana-lyzer results and the average laboratory results using theStudents t test at 95 % confidence coefficient, two-tailed testas described in 14.1. Passing the Students t test signifies thecontinuous analyzers average analysis of the reference sampl
31、eis not statistically significantly different from the laboratoryanalyzers average analysis of the same reference sample(validation test acceptable). Failing the 88t” test signifies astatistically significant difference exists (validation test notacceptable).3.2.18.2 line sample validationsa line sa
32、mple is analyzedcoincidentally a minimum of seven times by an appropriatecontinuous analyzer and an appropriate laboratory analyzer ora second continuous analyzer. A comparison is made on thedifferences between the coincidental results using the Studentst test at 95 % confidence coefficient, two-tai
33、led test, to evaluatewhether the average difference is statistically significantlydifferent from zero difference as described in 14.2.3.2.19 verificationa periodic or routine procedure to en-sure reliability of analytical results.3.2.19.1 line sample verificationa line sample is analyzedas described
34、 in 3.2.18.2, and the results of the differencebetween the continuous analyzer and the laboratory analyzer ora second continuous analyzer is plotted on a control chart. Ifthe calculated difference between the continuous analyzer andthe laboratory analyzer or a second continuous analyzer iswithin 63
35、Sd, the continuous analyzer is considered verified. Ifthe calculated difference is outside 63 Sdthe continuousanalyzer is considered out of control (not verified).3.2.19.2 reference sample verificationa reference sampleis analyzed as described in 3.2.18.1 and the results of thedifferences between th
36、e continuous analyzer and the laboratoryanalyzer are plotted on a control chart. If the calculateddifference between the continuous analyzer and the laboratoryanalyzer is within 63 Sdthe continuous analyzer is consideredverified. If the calculated difference is outside 63 Sdthecontinuous analyzer is
37、 considered out of control (not verified).4. Summary of Guide4.1 This guide provides a unified approach to the use ofon-line monitoring systems for water quality analysis. Itpresents definitions of terms, safety precautions, system designand installation considerations, calibration techniques, gener
38、alD 3864 062operating procedures, and comments relating to validation andverification procedures.5. Significance and Use5.1 Many of the manual and automated laboratory methodsfor measurement of physical, chemical, and biological param-eters in water and waste water are adaptable to on-linesampling a
39、nd analysis. The resulting real-time data output canhave a variety of uses, including confirming regulatory com-pliance, controlling process operations, or detecting leaks orspills.5.2 This guide is intended to be a common reference thatcan be applied to all water quality monitoring systems.However,
40、 calibration, validation, and verification sections maybe inappropriate for certain tests since the act of removing asample from a flowing stream may change the sample.5.3 Technical details of the specific methodology are con-tained in the pertinentASTM standard test methods, which willreference thi
41、s practice for guidance in selection of systems andtheir proper implementation.5.4 This guide complements descriptive information on thissubject found in the ASTM Manual on Water.46. Reagents6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is in
42、tended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Soci-ety.5Other grades may be used, provided it is first ascertainedthat the reagent is of sufficiently high purity to permit its usewithout lessening the accuracy of the det
43、ermination.6.2 Purity of Water Unless otherwise indicated, the ref-erence to water shall be understood to mean reagent water thatmeets the purity specification of Specification D 1193 TypeIorType II water.7. Hazards7.1 Each analyzer installation shall be given a thoroughsafety engineering study.67.2
44、 Electrically, the monitoring system as well as theindividual components, shall meet all code requirements forthe particular area classification.7.2.1 All analyzers using 120 V, alternating current, 60 Hz,3-wire systems shall observe polarity and shall not use me-chanical adapters for 2-wire outlets
45、.7.2.2 Check the neutral side of the power supply at theanalyzer to see that it is at ground potential.7.2.3 Connect the analyzers ground connection to earthground and check for proper continuity.7.2.4 The metallic framework of the analyzer shall be atground potential.7.2.5 Consider additional prote
46、ction in the form of properlysized ground fault interrupters for each individual application.7.2.6 Analyzers containing electrically heated sections shallhave a temperature-limit device.7.2.7 The analyzer, and any related electrical equipment (thesystem), shall have a properly sized power cutoff swi
47、tch and afuse or breaker on the “hot” side of the line(s) of each device.7.3 Give full consideration to safe disposal of the analyzersspent samples and reagents.7.4 Provide pressure relief valves, if applicable, to protectboth the analyzer and monitoring system.7.5 Take precautions when using cylind
48、ers containing gasesor liquids under pressure. Helpful guidance may be obtainedfrom Refs (14).77.5.1 Gas cylinders must be handled by trained personnelonly.7.5.2 Fasten gas cylinders to a rigid structure.7.5.3 Take special safety precautions when using or storingcombustible or toxic gases to ensure
49、that the system is safe andfree from leaks.7.6 Gas piping, where possible, shall be metallic, especiallyinside the analyzer housing.8. Measurement Objectives8.1 Carefully define the measurement objective for themonitoring system before selecting components of the systemand set specifications realistically, to meet the objective. Termsused as specifications shall be consistent with the terminologyin Section 3.8.2 If the monitoring system is intended primarily to deter-mine compliance with regulatory standards, the accuracy,precision, fre
