ASTM D3864-12(2021)

Standard Guide for On-Line Monitoring Systems for Water Analysis

ABSTRACT
This guide covers the selection, establishment, application, and validation and verification of monitoring systems for determining water characteristics by continual sampling, automatic analysis, and recording or otherwise signaling of output data. This guide provides a unified approach to the use of on-line monitoring systems for water quality analysis. Safety precautions, system design and installation, calibration techniques, operating procedures, and validation and verification procedures shall be in accordance with the specified requirements.
SIGNIFICANCE AND USE
5.1 Many of the manual and automated laboratory methods for measurement of physical, chemical, and biological parameters in water and waste water are adaptable to on-line sampling and analysis. The resulting real-time data output can have a variety of uses, including confirming regulatory compliance, controlling process operations, or detecting leaks or spills.  
5.2 This guide is intended to be a common reference that can be applied to all water quality monitoring systems. However, calibration, validation, and verification sections may be inappropriate for certain tests since the act of removing a sample from a flowing stream may change the sample.  
5.3 Technical details of the specific methodology are contained in the pertinent ASTM standard test methods, which will reference this standard for guidance in selection of systems and their proper implementation.  
5.4 This guide complements descriptive information on this subject found in the ASTM STP 442.
SCOPE
1.1 This guide covers the selection, establishment, application, and validation and verification of monitoring systems for determining water characteristics by continual sampling, automatic analysis, and recording or otherwise signaling of output data. The system chosen will depend on the purpose for which it is intended: whether it is for regulatory compliance, process monitoring, or to alert the user of adverse trends. If it is to be used for regulatory compliance, the method published or referenced in the regulations should be used in conjunction with this guide and other ASTM methods.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 7.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Dec-2020
• ICS: 13.060.50 - Examination of water for chemical substances
• Technical Committee: D19 - Water
• Drafting Committee: D19.03 - Sampling Water and Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, On-Line Water Analysis, and Surveillance of Water

Relations

• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM E178-16 - Standard Practice for Dealing With Outlying Observations
• Effective Date: 01-Jun-2016
• Refers: ASTM D3370-10 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM E178-08 - Standard Practice for Dealing With Outlying Observations
• Effective Date: 01-Oct-2008
• Refers: ASTM D5540-08 - Standard Practice for Flow Control and Temperature Control for On-Line Water Sampling and Analysis
• Effective Date: 01-Oct-2008
• Refers: ASTM D3370-08 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Oct-2008
• Refers: ASTM D3370-07 - Standard Practices for Sampling Water from Closed Conduits
• Effective Date: 01-Dec-2007
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1193-06 - Standard Specification for Reagent Water
• Effective Date: 01-Mar-2006
• Refers: ASTM D1129-06 - Standard Terminology Relating to Water
• Effective Date: 15-Feb-2006
• Refers: ASTM D1129-04e1 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-04 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2004
• Refers: ASTM D1129-03a - Standard Terminology Relating to Water
• Effective Date: 10-Aug-2003

Overview

ASTM D3864-12(2021), Standard Guide for On-Line Monitoring Systems for Water Analysis, provides comprehensive guidance for the selection, establishment, application, and validation of on-line monitoring systems used in water analysis. Published and maintained by ASTM International, this guide serves as a unified approach for continuously assessing water characteristics using automatic sampling, analysis, and recording technologies. The standard is aimed at ensuring accurate, reliable, and real-time water quality data for applications ranging from regulatory compliance to process control and environmental protection.

Key Topics

• System Selection and Application: The guide outlines criteria for choosing appropriate on-line monitoring systems based on specific water analysis objectives such as regulatory compliance, process performance, or early detection of spills and leaks.
• System Design and Installation: It addresses factors in designing and installing these systems, emphasizing sample integrity, compatibility of materials, ease of maintenance, and environmental resilience.
• Calibration, Validation, and Verification: Detailed guidance is provided for developing and implementing calibration procedures, validation of system accuracy, and routine verification to ensure long-term system reliability.
• Safety and Good Practice: ASTM D3864 emphasizes the need for thorough safety studies, adherence to electrical codes, proper disposal of chemicals, and robust installation practices to safeguard both personnel and equipment.
• Terminology and Measurement: The standard provides standardized definitions and precise terms for calibration procedures, measurement limits, sampling intervals, and system performance evaluation.

Applications

The practical value of ASTM D3864-12(2021) lies in its broad applicability across industries requiring real-time water quality monitoring. Typical applications include:

• Industrial Process Monitoring: Continuous monitoring of cooling water, boiler feeds, or effluent streams to optimize production efficiency and prevent damage or downtime.
• Regulatory Compliance: Providing real-time data to confirm that process discharges or potable water supplies meet environmental and health regulations.
• Environmental Protection: Early detection of leaks, spills, and pollution events in water bodies to trigger alerts or automated interventions.
• Water and Wastewater Treatment: Ensuring operational control in municipal and industrial treatment plants by facilitating accurate adjustment of treatment processes based on up-to-date water quality data.
• Research and Quality Assurance: Supporting data collection for environmental studies or quality assurance programs where reliable, high-frequency data is required.

This standard encourages the use of advanced monitoring technologies such as sensors, analyzers, and data acquisition systems, all integrated to provide a streamlined water analysis solution.

Related Standards

For complete implementation and best practices, ASTM D3864-12(2021) references several other important standards:

• ASTM D1129: Terminology Relating to Water
• ASTM D1193: Specification for Reagent Water
• ASTM D3370: Practices for Sampling Water from Flowing Process Streams
• ASTM D5540: Practice for Flow Control and Temperature Control for On-Line Water Sampling and Analysis
• ASTM E178: Practice for Dealing With Outlying Observations

Additionally, the guide complements information in ASTM Special Technical Publication 442 (STP 442), Manual on Water, offering further insights for professionals in water monitoring systems.

Summary

By following ASTM D3864-12(2021), organizations benefit from a robust framework for implementing on-line water quality monitoring systems. This ensures greater confidence in water data integrity, supports compliance and operational goals, and helps protect the environment through effective, immediate response to water quality changes. For industries and utilities looking to upgrade their water analysis capabilities, this standard is an essential reference for quality, safety, and reliability in automated water monitoring.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D3864 − 12 (Reapproved 2021)
Standard Guide for
On-Line Monitoring Systems for Water Analysis
This standard is issued under the fixed designation D3864; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D4210Practice for Intralaboratory Quality Control Proce-
dures and a Discussion on Reporting Low-Level Data
1.1 This guide covers the selection, establishment,
(Withdrawn 2002)
application, and validation and verification of monitoring
D5540Practice for Flow Control and Temperature Control
systems for determining water characteristics by continual
for On-Line Water Sampling and Analysis
sampling, automatic analysis, and recording or otherwise
E178Practice for Dealing With Outlying Observations
signalingofoutputdata.Thesystemchosenwilldependonthe
2.2 ASTM Special Technical Publication:
purpose for which it is intended: whether it is for regulatory
STP 442Manual on Water
compliance, process monitoring, or to alert the user of adverse
trends.Ifitistobeusedforregulatorycompliance,themethod
3. Terminology
published or referenced in the regulations should be used in
3.1 Definitions:
conjunction with this guide and other ASTM methods.
3.1.1 For definitions of terms used in this standard, refer to
1.2 The values stated in SI units are to be regarded as
Terminology D1129.
standard. No other units of measurement are included in this
standard. 3.2 Definitions of Terms Specific to This Standard:
3.2.1 Calibrations:
1.3 This standard does not purport to address all of the
3.2.1.1 laboratory calibration curve for flow-through
safety concerns, if any, associated with its use. It is the
systems, n—calibration curve calculated from withdrawn
responsibility of the user of this standard to establish appro-
samples or additional standards that may be spiked or diluted
priate safety, health, and environmental practices and deter-
and analyzed using the appropriate laboratory analyzer.
mine the applicability of regulatory limitations prior to use.
Specific hazard statements are given in Section 7. 3.2.1.2 laboratory calibration curve for flow-through
systems, n—type of sample used to generate a laboratory
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- calibration curve for flow-through systems.
ization established in the Decision on Principles for the
3.2.1.3 line sample calibration, n—coincidentalcomparison
Development of International Standards, Guides and Recom-
ofalinesampleandadjustmentofacontinuousanalyzertothe
mendations issued by the World Trade Organization Technical
comparedlaboratoryanalyzerorasecondcontinuousanalyzer.
Barriers to Trade (TBT) Committee.
3.2.1.4 multiple standard calibration, n—where the calibra-
tion curve is calculated from a series of calibration standards
2. Referenced Documents
covering the range of the measurements of the sample being
2.1 ASTM Standards:
analyzed.
D1129Terminology Relating to Water
3.2.1.5 probe calibration, n—where the probe is removed
D1193Specification for Reagent Water
from the sample stream and exposed to a calibration solution
D3370Practices for Sampling Water from Flowing Process
and the analyzer is adjusted to indicate the appropriate value.
Streams
Alternately, two probes are exposed to the same solution and
the on-line analyzer is adjusted to coincide with the pre-
This guide is under the jurisdiction ofASTM Committee D19 on Water and is
calibrated laboratory instrument.
the direct responsibility of Subcommittee D19.03 on Sampling Water and Water-
3.2.1.6 reference sample calibration, n—coincidental com-
Formed Deposits, Analysis of Water for Power Generation and Process Use,
On-Line Water Analysis, and Surveillance of Water.
parison of a reference sample and adjustment of a continuous
Current edition approved Jan. 1, 2021. Published January 2021. Originally
analyzer to the compared laboratory analyzer results.
approved in 1979. Last previous edition approved in 2012 as D3864–12. DOI:
10.1520/D3864-12R21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM The last approved version of this historical standard is referenced on
Standards volume information, refer to the standard’s Document Summary page on www.astm.org.
the ASTM website. Available from ASTM International Headquarters.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3864 − 12 (2021)
3.2.2 cycle time, n—the interval between repetitive sample 3.2.15 response time, n—the time interval from a step
introductions in a monitoring system with discrete sampling. change in the input or output reading to 90% of the ultimate
reading.
3.2.3 drift, n—the change in system output, with constant
3.2.15.1 lag time, n—thetimeintervalfromastepchangein
input over a stated time period of unadjusted, continuous
operation; usually expressed as percentage of full scale over a input to the first corresponding change in output.
24-h period.
3.2.15.2 total time, n—the time interval from a step change
in the input to a constant analyzer signal output.
3.2.3.1 span drift, n—drift when the input is at a constant,
stated upscale value.
3.2.16 sampleport,n—thatpointinthesample-conditioning
system where samples for laboratory analysis are taken.
3.2.3.2 zero drift, n—drift when the input is at zero.
3.2.17 samples:
3.2.4 full scale, n—the maximum measuring limit of the
3.2.17.1 line sample, n—a process sample withdrawn from
system for a given range.
the sample port (3.2.16) during a period when the process
3.2.5 input, n—thevalueoftheparameterbeingmeasuredat
stream flowing through the continuous analyzer is of uniform
the inlet to the analyzer.
qualityandtheanalyzerresultdisplayedisessentiallyconstant.
3.2.6 interference, n—an undesired output caused by a
Laboratory tests or results from a second continuous analyzer
substance or substances other than the one being measured.
are obtained from each sample and compared with the con-
3.2.6.1 Discussion—The effect of interfering substance(s)
tinuous analyzer results obtained at the time of sampling.
on the measured parameter of interest should be expressed as
3.2.17.2 reference sample, n—can be a primary standard or
a percentage change (6) in the measured component as the
adilutionofaprimarystandardofknownreferencevalue.The
interference varies from 0 to 100% of the measuring scale. If
reference value must be established through multiple testing
theinterferenceisnonlinear,analgebraicexpressionshouldbe
using an appropriate ASTM or other standard laboratory test
developed (or curve plotted) to show the varying effect.
method.Bulkquantitiesofthereferencesamplemustbestored
3.2.7 laboratory analyzer, n—a device that measures the
and handled to avoid contamination or degradation. One or
chemical composition or a specific physical, chemical, or
more reference samples encompassing the range of the ana-
biological property of a sample.
lyzer may be required.
3.2.17.2 (1) Discussion—It is essential that the laboratory
3.2.8 limit of detection, n—a concentration of twice the
analyzer be checked carefully before these tests are performed
criterion of detection when it has been decided that the risk of
toensurecompliancewiththerequirementsofthestandardtest
making a Type II error is equal to a Type I error as described
procedure. To further ensure proper operation, it is recom-
in Practice D4210.
mended that a previously calibrated reference sample or an
3.2.9 linearity, n—the extent to which an actual analyzer
in-house control standard of known concentration be tested to
reading agrees with the reading predicted by a straight line
validate the operations of the laboratory analyzer.
drawnbetweenupperandlowercalibrationpoints—generally
3.2.18 validations, n—a one-time comprehensive examina-
zero and full-scale. (The maximum deviation from linearity is
tion of analytical results.
frequently expressed as a percentage of full-scale.)
3.2.18.1 line sample validations, n—a line sample is ana-
3.2.10 monitoring system, n—the integrated equipment
lyzed coincidentally a minimum of seven times by an appro-
package comprising sampling system, analyzer, and data out-
priate continuous analyzer and an appropriate laboratory ana-
put equipment, required to perform water quality analysis
lyzer or a second continuous analyzer. A comparison is made
automatically.
on the differences between the coincidental results using the
3.2.10.1 analyzer, n—adevicethatcontinuallymeasuresthe
Student’s t test at 95% confidence coefficient, two-tailed test,
specificphysical,chemical,orbiologicalpropertyofasample.
to evaluate whether the average difference is statistically
3.2.10.2 data acquisition equipment, n—analog or digital significantlydifferentfromzerodifferenceasdescribedin14.2.
devices for acquiring, processing, or recording, or a combina-
3.2.18.2 reference sample validations, n—a reference
tion thereof, the output signals from the analyzer.
sample is analyzed a minimum of seven times by an appropri-
ate continuous analyzer and by an appropriate laboratory
3.2.10.3 sampling system, n—equipment necessary to de-
liver a continual representative sample to the analyzer. analyzer.Acomparison is made between the average continu-
ous analyzer results and the average laboratory results using
3.2.11 output, n—a signal, usually electrical, that is related
the Student’s t test at 95% confidence coefficient, two-tailed
totheparametricmeasurementandistheintendedinputtodata
test as described in 14.1. Passing the Student’s t test signifies
acquisition equipment.
the continuous analyzer’s average analysis of the reference
3.2.12 range, n—the region defined by the minimum and
sample is not statistically significantly different from the
maximum measurable limits.
laboratory analyzer’s average analysis of the same reference
3.2.13 repeatability, n—a measure of the precision of one
sample(validationtestacceptable).Failingthe“t”testsignifies
analyzertorepeatitsresultsonindependentintroductionofthe
a statistically significant difference exists (validation test not
same sample at different time intervals.
acceptable).
3.2.14 reproducibility, n—a measure of the precision of 3.2.19 verification, n—a periodic or routine procedure to
different analyzers to repeat results on the same sample. ensure reliability of analytical results.
D3864 − 12 (2021)
3.2.19.1 line sample verification, n—a line sample is ana- teeonAnalyticalReagentsoftheAmericanChemicalSociety.
lyzed as described in 3.2.18.1, and the results of the difference Other grades may be used, provided it is first ascertained that
betweenthecontinuousanalyzerandthelaboratoryanalyzeror the reagent is of sufficiently high purity to permit its use
a second continuous analyzer is plotted on a control chart. If without lessening the accuracy of the determination.
the calculated difference between the continuous analyzer and
6.2 Purity of Water—Unless otherwise indicated, the refer-
the laboratory analyzer or a second continuous analyzer is
ence to water shall be understood to mean reagent water that
within 63 S ,thecontinuousanalyzerisconsideredverified.If
d
meetsthepurityspecificationofSpecificationD1193TypeIor
the calculated difference is outside 63 Sd the continuous
Type II water.
analyzer is considered out of control (not verified).
7. Hazards
3.2.19.2 reference sample verification, n—a reference
7.1 Each analyzer installation shall be given a thorough
sample is analyzed as described in 3.2.18.2 and the results of
safety engineering study.
the differences between the continuous analyzer and the
laboratory analyzer are plotted on a control chart. If the
7.2 Electrically, the monitoring system as well as the
calculated difference between the continuous analyzer and the
individual components, shall meet all code requirements for
laboratory analyzer is within 63 S the continuous analyzer is
d the particular area classification.
considered verified.
7.2.1 All analyzers using 120 V, alternating current, 60 Hz,
3.2.19.2 (1) Discussion—If the calculated difference is out-
3-wire systems shall observe polarity and shall not use me-
side 63 S , the continuous analyzer is considered out of
chanical adapters for 2-wire outlets.
d
control (not verified).
7.2.2 Check the neutral side of the power supply at the
analyzer to see that it is at ground potential.
3.3 Symbols:
7.2.3 Connect the analyzer’s ground connection to earth
S = standard deviation
ground and check for proper continuity.
d
7.2.4 The metallic framework of the analyzer shall be at
4. Summary of Guide ground potential.
7.2.5 Consider additional protection in the form of properly
4.1 This guide provides a unified approach to the use of
sized ground fault interrupters for each individual application.
on-line monitoring systems for water quality analysis. It
7.2.6 Analyzerscontainingelectricallyheatedsectionsshall
presentsdefinitionsofterms,safetyprecautions,systemdesign
have a temperature-limit device.
and installation considerations, calibration techniques, general
7.2.7 Theanalyzer,andanyrelatedelectricalequipment(the
operating procedures, and comments relating to validation and
system), shall have a properly sized power cutoff switch and a
verification procedures.
fuse or breaker on the “hot” side of the line(s) of each device.
7.3 Givefullconsiderationtosafedisposaloftheanalyzer’s
5. Significance and Use
spent samples and reagents.
5.1 Many of the manual and automated laboratory methods
7.4 Provide pressure relief valves, if applicable, to protect
for measurement of physical, chemical, and biological param-
both the analyzer and monitoring system.
eters in water and waste water are adaptable to on-line
sampling and analysis. The resulting real-time data output can 7.5 Takeprecautionswhenusingcylinderscontaininggases
have a variety of uses, including confirming regulatory or liquids under pressure. Helpful guidance may be obtained
from Refs (1-4).
compliance, controlling process operations, or detecting leaks
or spills. 7.5.1 Gas cylinders must be handled by trained personnel
only.
5.2 This guide is intended to be a common reference that
7.5.2 Fasten gas cylinders to a rigid structure.
can be applied to all water quality monitoring systems.
7.5.3 Take special safety precautions when using or storing
However, calibration, validation, and verification sections may
combustibleortoxicgasestoensurethatthesystemissafeand
be inappropriate for certain tests since the act of removing a
free from leaks.
sample from a flowing stream may change the sample.
7.6 Gas piping, where possible, shall be metallic, especially
5.3 Technical details of the specific methodology are con-
inside the analyzer housing.
tainedinthepertinentASTMstandardtestmethods,whichwill
referencethisstandardforguidanceinselectionofsystemsand
ACS Reagent Chemicals, Specifications and Procedures for Reagents and
their proper implementation.
Standard-Grade Reference Materials, American Chemical Society, Washington,
DC. For suggestions on the testing of reagents not listed by theAmerican Chemical
5.4 This guide complements descriptive information on this
Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
subject found in the ASTM STP 442.
U.K., and the United States Pharmacopeia and National Formulary, U.S. Pharma-
copeial Convention, Inc. (USPC), Rockville, MD.
The user, equipment, supplier, and installer should be familiar with require-
6. Reagents
ments of the National Electrical Code, any local applicable electrical code, UL
Safety Codes, and the Occupational Safety and Health Standards (see Federal
6.1 Purity of Reagents—Reagent grade chemicals shall be
Register, Vol 36, No. 105, Part II, May 29, 1971).
used in all tests. Unless otherwise indicated, it is intended that
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof
all reagents shall conform to the specifications of the Commit- this standard.
D3864 − 12 (2021)
8. Measurement Objectives 9.4 Select the sampling point(s) so as to provide a repre-
sentative and measurable sample as close as possible to the
8.1 Carefully define the measurement objective for the
sample system and analyzer, and as outlined in Practices
monitoring system before selecting components of the system
D3370.
andsetspecificationsrealistically,tomeettheobjective.Terms
9.5 Design the sample probe to be consistent with the
used as specifications shall be consistent with the terminology
measurement objective and to require a minimum of mainte-
in Section 3.
nance.
8.2 If the monitoring system is intended primarily to deter-
9.6 Select the sample transfer system, including pumps and
mine compliance with regulatory standards, the accuracy,
transfer lines, so that the integrity of the sample is maintained
precision, frequency of sampling, and response time may be
from sampling point to analyzer, especially with respect to
dictated by the requirements of the regulations.Ahigh degree
suspension of solids and biological growth.
of stability and on-line reliability is generally required. The
9.7 Provide necessary sample conditioning equipment (for
analyzer response for a specific parameter must be referenced
example,filters,diluters,homogenizers,streamsplitters)thatis
toarecognizedorspecifiedlaboratorymethodapprovedbythe
consistent with the defined measurement objective.
regulatory agency.
9.8 Provide a connection, when necessary, for introducing
8.3 Monitoring systems intended to detect leaks and uncon-
standard samples or withdrawing check samples immediately
trolled discharges, that is, spills, to protect treatment plants or
upstream of the analyzer.
receiving waters, require short sampling cycles and rapid
response.Typically,thesewillactivatealarmstoalertoperating
9.9 Keepsingle-ormultiple-samplestreamsthatinterfacea
personnel. They then may cause flow to be diverted from
singleanalyzerflowingallthetime.Keepthemanifoldcloseto
normal channels until the upset has passed or has been
the analyzer to minimize cross-contamination.
corrected. Frequently, the monitoring system is used in some
9.10 Always keep sample lines as short as possible.
way to locate and identify the source of the spill.
9.11 Provide appropriate protection of sample lines from
8.4 Systemsthatmonitortheperformanceofprocessopera-
extremely hot or freezing temperatures.
tions such as waste treatment, may have varying degrees of
sophisticationandcomplexity,dependingonthespecificnature
10. Considerations for Analyzer Selection
of the application.
10.1 The analyzer selected must meet the measurement
8.4.1 Simple,inexpensive,andlow-precisionanalyzerswith
objectiveofthesystemoverthecompleterangeofapplication.
indicating or recording devices and alarms are acceptable for
10.1.1 Precisionandaccuracyofmeasurementandresponse
monitoring trends in operating parameters and for alerting
time for the parameter of interest shall coincide with system
operating personnel to off-standard performance.
specifications at all levels of measurement.
8.4.2 Monitoring systems that provide data to be used to
10.1.2 Interference shall be insignificant relative to the
manually control process operations or to manually set auto-
measured component or shall be controllable. When used for
matic controllers are generally more complex and frequently
regulatorycompliance,knowninterferencesshallnotaffectthe
require that outputs be transmitted long distances.
reading more than 5% from the true value.
8.4.3 Monitoring systems intended to process data for
10.1.3 If required for compliance, the analyzer shall be
operatingguidanceormanagementpresentationandtoprovide
capableofvalidationbycalibrationwithapprovedandcertified
varying degrees of automatic process control must be compat-
standard reference materials using standardASTM (or equiva-
ible with digital computers or telemetering systems. The
lent) tests.
reliability and stability of such systems, particularly the data
10.2 In choosing a specific analyzer for a specific
output equipment, shall be high.
application, on line reliability of the instrument is of prime
concern.
9. Sample System Design Considerations
10.2.1 Downtime for maintenance because of component
9.1 Carefully examine the measurement objectives of the failures or other malfunction shall be minimal. Ease,
monitoring system and select a sampling system that matches
promptness, minimal cost of repair or replacement are essen-
these requirements. tial.
10.2.2 The analyzer shall be stable. Drift and changes in
9.2 Review all sample requirements with the equipment
responsewithchangesinconditionssuchasflowandtempera-
supplier.Besuretodefineaccuratelyallconditionsofintended
ture shall be insignificant or means for compensation shall be
operation, the components in the sample and expected varia-
provided. Sample flow variations may have a significant effect
tions in the measured parameters.
on measured analyte concentrations. Flow rate control shall be
9.3 Choose materials of construction for the parts that will established as specified in Practice D5540. Sample flow rate
beincontactwiththesample,thatdonotreactwiththesample shall be maintained within limits to maintain the necessary
tocausesubsequentcontamination,corrosion,orotherdamage precision of the continuous on line monitor.
to critical parts or sorption of measurable components and 10.2.3 The analyzer shall be relatively simple and easy to
maintain sample integrity. operate and maintain at a satisfactory level of performance.
D3864 − 12 (2021)
11. Data Output Equipment Considerations 13.1.3 Refer to ASTM standards, where applicable, to
determine appropriate calibration standards.
11.1 Equipment for the acquisition of output data from the
13.1.4 Provide calibration standards at concentrations and
analyzer shall meet the requirements of the measuring objec-
compositionsascloseaspossibletothoseofthesamplestream
tives for the monitoring system.
being analyzed.
11.2 Visual or audible alarms and simple output meters are
13.1.5 Before calibration, ensure that the sampling system
acceptable and desirable in many applications.
andoutputinstrumentationarefunctioningproperlyandthatall
11.3 Theanalyzeroutputcanberecordedlocallyatthefield preliminary adjustments to the analyzer required by the proce-
dure have been made.
location. The digital or analog signal is frequently transmitted
toacentralizedlocation,suchasacontrolroom,oftenbyadata
NOTE 1—Flow rate changes may affect continuous on line analyzer
line shared with other instruments.
measured analyte concentration. If flow rates cannot be maintained
constant, the effect of flow rate variation on measured analyte concentra-
11.4 Records or real-time data can be transferred to com-
tion shall be evaluated. Limits for flow rate variation shall be established
puters for storage, process control, or report generation.
to maintain the necessary precision of the continuous on line monitor.
11.5 Process equipment such as valves and pumps can be
13.2 Reference Sample Calibration:
actuatedbyoutputgeneratedbyanalyzersinanumberofways:
13.2.1 Withthereferencesampleflowinguniformlythrough
11.5.1 Recorded and output meters can have set points as
the analyzer sampling line, allow the continuous analyzer
integral parts of their design which actuate the equipment
readout to equilibrate.
directly for either on-off or proportional control.
13.2.2 Record time, sample number, date, and the corre-
11.5.2 Controllers can be manually adjusted in response to
sponding continuous analyzer readout, and immediately ana-
analyzer signals read from a recorder or from output presented
lyze the reference sample using the appropriate laboratory
in a data report, typed or displayed on a cathode ray tube.
analysis test method.
11.5.3 Direct digital process control is possible in more
13.2.3 Determine the continuous analyzer calibration ad-
complicated and sophisticated systems, where real-time ana-
justment required so that results of laboratory analysis and the
lyzer output is integrated with other process data and used to
continuous analyzer readout coincide. Adjust the analyzer
maintain desirable process conditions.
controls accordingly.
13.2.4 Repeat this procedure until no further change is
12. Installation of Monitoring System
needed, consistent with the quality of data required.
12.1 Obtain information required for installation and opera-
13.3 Line Sample Calibration:
tion of the monitoring system from the supplier.
13.3.1 With the sample flowing through the continuous
12.2 Study operational data and design parameters fur-
analyzer sampling line uniformly and the continuous analyzer
nished by the supplier before installation.
readout as close as possible to an equilibrium value, connect a
second on line analyzer either downstream or on a parallel
12.3 Choose materials of construction and components of
sample line, or withdraw a sample from the inlet stream as
the monitoring system to withstand the environment in which
described in Practices D3370.
it is installed.
NOTE 2—The connection should be made in such a way so as not to
12.4 Select a location for the analyzer that is as close as
contaminate the flowing sample.
possible to the sample intake and which provides adequate
protection from extremes of temperature and humidity, where 13.3.2 Record time, date, continuous analyzer results and
thesecondonlineanalyzerresults,orimmediatelyanalyzethe
this is essential for proper performance.
withdrawn sample using the appropriate laboratory analysis
12.5 Provide a convenient access to the entire monitoring
test method.
system.
13.3.3 Determine the continuous analyzer calibration ad-
12.6 Provide proper outlets for the analyzer’s exit streams
justment required so that the results of the on line continuous
so that no liquid or gas pressure buildup occurs (see 7.4).
analyzers agree with the second on line analyzer or the
laboratory analysis.
12.7 After the installation has been completed, allow the
analyzer to stabilize and calibrate before testing performance
NOTE 3—It is essential that the second on line continuous analyzer be
specifications.
checked carefully before this calibration is performed to ensure compli-
ance with the requirements of the standard test procedure. To further
13. Calibration
ensure proper operation it is recommended that a reference sample or
in-house control standard of known quality be tested to validate the
13.1 Establishawrittencalibrationprocedureandfrequency
operation of the second on line continuous analyzer.
consistentwiththeparameterbeingmeasuredandtheaccuracy
13.3.4 Adjust the continuous analyzer with the analyzer
and reliability demanded by the measurement or control
controls accordingly.
objectives based on the following:
13.1.1 Consult the analyzer supplier to determine the best 13.4 Multiple Standard Calibration:
calibration procedure to use with the specific analyzer in a 13.4.1 Prepare a series of calibration standards covering the
particular application. range of measurements for the sample being analyzed, follow-
13.1.2 When required for regulatory compliance, use cali- ing instructions in the test method or in the analyzer supplier’s
bration procedures specified by the appropriate agency. instructions.
D3864 − 12 (2021)
13.4.2 Check all operating conditions of the system in 13.6.6 Rinse the probe thoroughly, place it in a second
accordance with the analyzer specifications, and allow suffi- container containing the other calibration solution and readjust
cient time for instrument equilibrium. the controls, if necessary, so that the output agrees with the
value of this guide.
13.4.3 Introduce a calibration standard of a concentration
13.6.7 Recheck with both solutions at least once. If either
level recommended by the instrument supplier into the ana-
point differs from the true value by a significant amount, as
lyzer using the recommended instrument operating procedure.
determined by the quality of measurement required, perform
Activate the readout equipment.
necessary maintenance, and recalibrate.
13.4.4 After sufficient sample has been allowed to flow
13.6.8 Alternatively, insert a second probe, with indepen-
through the analyzer, adjust the readout to conform to the
dent readout equipment and previously calibrated, into the
desired value.
sample alongside the probe and calibrate in situ, by adjusting
13.4.5 Repeat 13.3.3 for the remaining standards from the
its controls until the outputs of the two probes coincide.
calibrationseries,recordingtheequilibriumreadoutvalueeach
time.
13.7 After initial calibration with standard solutions or
actual samples, as in 13.2 through 13.5, analyzer calibrations
13.4.6 Plot a calibration curve of standard value versus
can be rechecked with secondary standards.
readout response from the above data.
13.7.1 An electrical signal may be imposed to produce an
13.4.7 Discard any standard when any change of composi-
analyzer output corresponding to a specific value produced by
tion is detected.
the parameters being analyzed.
13.5 Laboratory Calibration Sample for Flow-Through Sys-
13.7.2 A solution containing material other than the com-
tem:
ponent of interest, but producing the same analyzer output as
13.5.1 Withdraw from the spot sampling line or otherwise
that component, may be used in place of the standard solution.
obtain directly from the sample stream sufficient sample for
13.7.3 An optical filter may be placed in the beam of a
calibration, representative of one concentration within the
photometric analyzer to produce an output equivalent to that
range of measurement of the analyzer (see Practices D3370).
produced by the component of interest.
13.5.2 Analyze the sample for the parameter of interest
using the appropriate laboratory analysis test method.
14. Validation Procedures
13.5.3 If necessary, prepare additional standards to cover
14.1 Reference Sample Validation Procedure:
the range of interest by dilution with reagent water or by
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