1、Designation: D3864 12Standard Guide forOn-Line Monitoring Systems for Water Analysis1This standard is issued under the fixed designation D3864; 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
2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the selection, establishment,application, and validation and verification of monitoringsystems for determining water characteri
3、stics by continualsampling, automatic analysis, and recording or otherwisesignaling of output data. The system chosen will depend on thepurpose for which it is intended: whether it is for regulatorycompliance, process monitoring, or to alert the user of adversetrends. If it is to be used for regulat
4、ory compliance, the methodpublished or referenced in the regulations should be used inconjunction with 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 this standard to e
5、stablish 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:2D1129 Terminology Relating to WaterD1193 Specification for Reagent WaterD3370 Practic
6、es for Sampling Water from Closed ConduitsD4210 Practice for Intralaboratory Quality Control Proce-dures and a Discussion on Reporting Low-Level Data(Withdrawn 2002)3D5540 Practice for Flow Control and Temperature Controlfor On-Line Water Sampling and AnalysisE178 Practice for Dealing With Outlying
7、Observations2.2 ASTM Special Technical Publication:STP 442 Manual on Water43. Terminology3.1 DefinitionsFor definitions of terms used in this guiderefer to Terminology D1129.3.2 Definitions of Terms Specific to This Standard:3.2.1 Calibrations:3.2.1.1 laboratory calibration curve for flow-throughsys
8、temscalibration curve calculated from withdrawn samplesor additional standards that may be spiked or diluted andanalyzed using the appropriate laboratory analyzer.3.2.1.2 laboratory calibration curve for flow-throughsystemstype of sample used to generate a laboratory calibra-tion curve for flow-thro
9、ugh systems.3.2.1.3 line sample calibrationcoincidental comparisonof a line sample and adjustment of a continuous analyzer to thecompared laboratory analyzer or a second continuous analyzer.3.2.1.4 multiple standard calibration where the calibra-tion curve is calculated from a series of calibration
10、standardscovering the range of the measurements of the sample beinganalyzed.3.2.1.5 probe calibrationwhere the probe is removedfrom the sample stream and exposed to a calibration solutionand the analyzer is adjusted to indicate the appropriate value.Alternately, two probes are exposed to the same so
11、lution andthe on-line analyzer is adjusted to coincide with the pre-calibrated laboratory instrument.3.2.1.6 reference sample calibration coincidental com-parison of a reference sample and adjustment of a continuousanalyzer to the compared laboratory analyzer results.3.2.2 cycle timethe interval bet
12、ween repetitive sampleintroductions in a monitoring system with discrete sampling.3.2.3 driftthe change in system output, with constant inputover a stated time period of unadjusted, continuous operation;usually expressed as percentage of full scale over a 24-hperiod.3.2.3.1 span driftdrift when the
13、input is at a constant,stated upscale value.3.2.3.2 zero driftdrift when the input is at zero.1This guide is under the jurisdiction of ASTM Committee D19 on Water and isthe direct responsibility of Subcommittee D19.03 on Sampling Water and Water-Formed Deposits, Analysis of Water for Power Generatio
14、n and Process Use,On-Line Water Analysis, and Surveillance of Water.Current edition approved June 1, 2012. Published October 2012. Originallyapproved in 1979. Last previous edition approved in 2006 as D3864 06. DOI:10.1520/D3864-12.2For referenced ASTM standards, visit the ASTM website, www.astm.org
15、, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from ASTM Headquarters. Contact Cu
16、stomer Service, 100 BarrHarbor Drive, West Conshohocken, PA 19428-2959.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 full scalethe maximum measuring limit of the sys-tem for a given range.3.2.5 inputthe value of the parameter
17、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.3.2.6.1 DiscussionThe effect of interfering substance(s)on the measured parameter of interest should be expressed asa percentage change (6) in the m
18、easured component as theinterference varies from 0 to 100 % of the measuring scale. Ifthe interference is nonlinear, an algebraic expression should bedeveloped (or curve plotted) to show the varying effect.3.2.7 laboratory analyzera device that measures thechemical composition or a specific physical
19、, chemical, 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 D4210.3.2.9 linearitythe extent to which an actual analyzerrea
20、ding agrees 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 samp
21、ling system, 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 acquirin
22、g, processing, or recording, or a combinationthereof, the output signals from the analyzer.3.2.10.3 sampling systemequipment necessary to deliver acontinual representative sample to the analyzer.3.2.11 outputa signal, usually electrical, that is related tothe parametric measurement and is the intend
23、ed input 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 measu
24、re of 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 o
25、utput.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 sample-conditioningsystem where samples for laboratory analysis are taken.3.2.17 samples:3.2.17.1 line samplea process sample withdrawn from thesample po
26、rt (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 continuous analyzerare obtained from each sample and compared with the con-tinuous analy
27、zer 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 testingusing an appropriate ASTM or other standard laboratory testmethod. Bulk quantiti
28、es 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 analyzer be checked carefullybefore these tests are performed to ensure complianc
29、e with the require-ments of the standard test procedure. To further ensure proper operation itis recommended that a previously calibrated reference sample or anin-house control standard of known concentration be tested to validate theoperations of the laboratory analyzer.3.2.18 validationsa one-time
30、 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.A comparison is made between the average continuous ana-lyzer results and the ave
31、rage 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 sampleis not statistically significantly different from the laboratoryanalyzers averag
32、e analysis of the same reference sample(validation test acceptable). Failing the t” test signifies astatistically significant difference exists (validation test notacceptable).3.2.18.2 line sample validationsa line sample is analyzedcoincidentally a minimum of seven times by an appropriatecontinuous
33、 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-tailed test, to evaluatewhether the average difference is statistically significantlyd
34、ifferent 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 in 3.2.18.2, and the results of the differencebetween the continuous analyzer and
35、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 Sd, the continuous analyzer is considered verified. Ifthe calculated difference is
36、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 theD3864 122differences between the continuous analyzer and the laboratoryanalyzer are plotted on a control
37、chart. If the calculateddifference between the continuous analyzer and the laboratoryanalyzer is within 63 Sdthe continuous analyzer is consideredverified.Discussion If the calculated difference is outside 63 Sdthe continuous analyzer is considered out of control (notverified).3.3 Symbols:Sd= standa
38、rd deviation4. 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, generaloperating procedures, and co
39、mments 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 and analysis. The resulting real-time dat
40、a output canhave a variety of uses, including confirming regulatorycompliance, controlling process operations, or detecting leaksor spills.5.2 This guide is intended to be a common reference thatcan be applied to all water quality monitoring systems.However, calibration, validation, and verification
41、 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 this practice for guidance in selection of sy
42、stems 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 intended thatall reagents shall conform to t
43、he 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 determination.6.2 Purity of Water Unless othe
44、rwise indicated, the refer-ence to water shall be understood to mean reagent water thatmeets the purity specification of Specification D1193 TypeIorType II water.7. Hazards7.1 Each analyzer installation shall be given a thoroughsafety engineering study.67.2 Electrically, the monitoring system as wel
45、l 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.7.2.2 Check the neutral side of the power
46、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 protection in the form of properlysized ground f
47、ault 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 switch and afuse or breaker on the “hot” side
48、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 cylinders containing gasesor liquids under pressu
49、re. 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 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
