ASTM D5540-13(2021)

Standard Practice for Flow Control and Temperature Control for On-Line Water Sampling and Analysis

SIGNIFICANCE AND USE
5.1 Sample conditioning systems must be designed to accommodate a wide range of sample source temperatures and pressures. Additionally, efforts must be made to ensure that the resultant sample has not been altered during transport and conditioning and has not suffered excessive transport delay. Studies have shown that sample streams will exhibit minimal deposition of ionic and particulate matter on wetted surfaces at specific flow rates (1-5). 3  
5.1.1 To ensure that the physical and chemical properties of the sample are preserved, this flow rate must be controlled throughout the sampling process, regardless of expected changes of source temperature and pressure, for example, during startup, or changing process operating conditions.  
5.2 The need to use analyzer temperature compensation methods is dependent on the required accuracy of the measurement. Facilities dealing with ultra-pure water will require both closely controlled sample temperature and temperature compensation to ensure accurate measurements. The temperature can be controlled by adding a second or trim cooling stage. The temperature compensation must be based on the specific contaminants in the sample being analyzed. In other facilities in which some variation in water chemistry can be tolerated, the use of either trim cooling or accurate temperature compensation may provide sufficient accuracy of process measurements. This does not negate the highly recommended practice of constant temperature sampling, especially at 25°C, as the most proven method of ensuring repeatable and comparable analytical results.  
5.3 A separate class of analysis exists that does not require or, in fact, cannot use the fully conditioned sample for accurate results. For example, the collection of corrosion product samples requires that the sample remain at near full system pressure, but cooled below the flash temperature, in order to ensure a representative collection of particulates. Only some of the primary conditioni...
SCOPE
1.1 This practice covers the conditioning of a flowing water sample for the precise measurement of various chemical and physical parameters of the water, whether continuous or grab. This practice addresses the conditioning of both high- and low-temperature and pressure sample streams, whether from steam or water.  
1.2 This practice provides procedures for the precise control of sample flow rate to minimize changes of the measured variable(s) due to flow changes.  
1.3 This practice provides procedures for the precise control of sample temperature to minimize changes of the measured variable(s) due to temperature changes.  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 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.  
1.6 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: 30-Jun-2021
• ICS: 13.060.10 - Water of natural resources
• ICS: 17.120.10 - Flow in closed conduits
• 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 D1066-18e1 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• Refers: ASTM D1066-18 - Standard Practice for Sampling Steam
• Effective Date: 01-Aug-2018
• Refers: ASTM D1066-11 - Standard Practice for Sampling Steam
• Effective Date: 15-Jun-2011
• 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 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 D1066-06 - Standard Practice for Sampling Steam
• Effective Date: 15-Dec-2006
• 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 D3864-06 - Standard Guide for Continual On-Line Monitoring Systems for Water Analysis
• Effective Date: 01-Jul-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

Overview

ASTM D5540-13(2021), Standard Practice for Flow Control and Temperature Control for On-Line Water Sampling and Analysis, provides essential guidelines for the conditioning of flowing water samples prior to on-line analysis. Developed by ASTM International, this standard outlines best practices for designing sample conditioning systems that ensure accurate and repeatable measurement of various chemical and physical water parameters. By focusing on both flow control and temperature regulation, ASTM D5540 helps facilities prevent sample alteration during transport, maintain integrity throughout sampling, and deliver reliable analytical results. The practice applies to a wide range of water and steam sampling scenarios, accommodating varying source temperatures, pressures, and analytical requirements.

Key Topics

• Sample Conditioning: Procedures to reduce and stabilize temperature and pressure of water or steam samples, while maintaining consistent flow from source to analysis.
• Flow Rate Control: Maintaining specified flow velocities is critical to minimize deposition of ionic and particulate matter in sample lines, preserving sample representativeness.
• Temperature Control: Emphasizes the importance of holding samples at a consistent temperature, typically 25°C, to ensure comparability and reproducibility in analytical results.
• Sample Integrity: Outlines strategies to avoid sample contamination or loss of analytes due to inappropriate materials, leaks, or system design.
• Pressure Regulation: Best practices for reducing and maintaining sample pressure, protecting both sample quality and laboratory or process equipment.
• Analyzer Compensation: When precise temperature control is challenging, application of analyzer temperature compensation is addressed, especially in ultra-pure water scenarios.
• Special Cases: Guidance for abnormal situations, such as when fully conditioned samples are not appropriate, for instance in corrosion product collection.

Applications

The implementation of ASTM D5540 is vital in several water and steam quality monitoring contexts, notably:

• Power Generation: On-line sampling of boiler feedwater or steam to control corrosion and scaling, ensuring plant efficiency and longevity.
• Industrial Water Treatment: Monitoring high- and low-pressure streams for process control and regulatory compliance.
• Ultra-Pure Water Systems: Semiconductor, pharmaceutical, and specialty manufacturing industries utilize this standard for stringent water purity requirements.
• Research Laboratories: Consistent sample preparation in experimental setups for accurate, reproducible data.

Key benefits include minimizing sample alteration during transport, ensuring data integrity, preventing equipment fouling, optimizing analyzer performance, and facilitating compliance with environmental and process standards.

Related Standards

ASTM D5540 integrates with and references several other important ASTM standards to provide a comprehensive approach to water sampling and analysis:

• ASTM D1129: Terminology Relating to Water-offers standardized definitions of relevant terms.
• ASTM D1066: Practice for Sampling Steam-supports steam sampling processes.
• ASTM D3370: Practices for Sampling Water from Flowing Process Streams-details procedures for representative water sampling in moving systems.
• ASTM D3864: Guide for On-Line Monitoring Systems for Water Analysis-covers design and operation of on-line water analysis systems.

Together, these standards form a coherent framework for effective on-line water sampling and analysis, supporting process reliability, regulatory adherence, and high-quality laboratory results.

Keywords: water sample conditioning, flow control, temperature control, on-line water analysis, ASTM D5540, sample cooler, pressure reduction, temperature compensation, industrial water monitoring, sample integrity.

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: D5540 − 13 (Reapproved 2021)
Standard Practice for
Flow Control and Temperature Control for On-Line Water
Sampling and Analysis
This standard is issued under the fixed designation D5540; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1129 Terminology Relating to Water
D3370 Practices for Sampling Water from Flowing Process
1.1 This practice covers the conditioning of a flowing water
Streams
sample for the precise measurement of various chemical and
D3864 Guide for On-Line Monitoring Systems for Water
physical parameters of the water, whether continuous or grab.
Analysis
This practice addresses the conditioning of both high- and
low-temperature and pressure sample streams, whether from
3. Terminology
steam or water.
3.1 Definitions:
1.2 This practice provides procedures for the precise control
3.1.1 For definitions of terms used in this standard, refer to
of sample flow rate to minimize changes of the measured
Terminology D1129.
variable(s) due to flow changes.
3.2 Definitions of Terms Specific to This Standard:
1.3 This practice provides procedures for the precise control
3.2.1 approach temperature, n—the difference in tempera-
of sample temperature to minimize changes of the measured
ture between cooling water temperature in and sample tem-
variable(s) due to temperature changes.
perature out.
1.4 The values stated in SI units are to be regarded as
3.2.1.1 Discussion—This term is used in heat exchanger
standard. The values given in parentheses after SI units are
applications and applies to all types of heat exchangers. The
provided for information only and are not considered standard.
term is defined as: the difference between the outlet tempera-
tureinonestreamandtheinlettemperatureintheotherstream.
1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3.2.2 crud deposition, n—on interior surfaces of sample
responsibility of the user of this standard to establish appro-
tubing or other hardware, the disposition of fine insoluble
priate safety, health, and environmental practices and deter-
particles (of iron oxides and other byproducts of metallic
mine the applicability of regulatory limitations prior to use.
corrosion) that are present throughout the system.
1.6 This international standard was developed in accor-
3.2.2.1 Discussion—The term “crud” is generally used for
dance with internationally recognized principles on standard-
all types of fouling.
ization established in the Decision on Principles for the
3.2.3 sample conditioning, n—reduction of the temperature
Development of International Standards, Guides and Recom-
and pressure of a flowing sample from process conditions to a
mendations issued by the World Trade Organization Technical
controlled temperature and pressure, and maintenance of a
Barriers to Trade (TBT) Committee.
constant flow rate both in incoming sample lines and through
on-line analyzers.
2. Referenced Documents
3.2.4 sample cooler, n—a small heat exchanger designed to
2.1 ASTM Standards:
cool small streams of water or steam.
D1066 Practice for Sampling Steam
3.2.5 temperature compensation, n—by the use of electronic
adjustment or data manipulation, the adjustment of the ana-
This practice is under the jurisdiction of ASTM Committee D19 on Water and
lyzer’s measured temperature for variation in sample tempera-
is the direct responsibility of Subcommittee D19.03 on Sampling Water and
Water-Formed Deposits, Analysis of Water for Power Generation and Process Use, ture from a preestablished value.
On-Line Water Analysis, and Surveillance of Water.
Current edition approved July 1, 2021. Published July 2021. Originally approved
4. Summary of Practice
in 1994. Last previous edition approved in 2013 as D5540 – 13. DOI: 10.1520/
D5540-13R21.
4.1 This practice covers the system design, operating
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
procedures, and selection of equipment to help ensure the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
appropriate flow and temperature control for analysis of water
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. and steam samples. This control is essential to ensure the
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5540 − 13 (2021)
accuracy and repeatability of on-line analyzers. Variations in 6.2 Studies (3-5) have shown that the loss of ionic and
types of analysis, sample characteristics, and their effect on particulate components is minimized by maintaining the water
sample conditioning are included. samplevelocityat1.8m/sinthesampletubingtransportingthe
sample. The turbulent flow at 1.8 m/s (6 ft/s) presents a stable
4.2 The equipment and procedures described in this practice
condition of deposition and removal. Changes in sample flow
are intended to represent current state-of-the art technology
rate or flow rates beyond a median range of approximately 1.8
available from major manufacturers of sample conditioning
m/s can upset this equilibrium condition.
equipment. Refer to Practices D1066 and D3370 and Guide
D3864 for additional information on sampling.
6.3 Saturated steam and superheated steam samples present
difficulttransportproblemsbetweenthesourceandtheprimary
5. Significance and Use
sample cooling equipment (4). Saturated steam samples with
5.1 Sample conditioning systems must be designed to ac-
transport velocities typically above 11 m/s (36 ft/s) provide
commodate a wide range of sample source temperatures and
adequate turbulent flow to ensure the transport of most
pressures.Additionally, efforts must be made to ensure that the
particulates and ionic components. Excessively large or small
resultant sample has not been altered during transport and
steam sample lines can affect the sample quality and quantity
conditioning and has not suffered excessive transport delay.
significantly. If the sample tubing has too large an inside
Studies have shown that sample streams will exhibit minimal
diameter, the steam velocity may be too low to transport the
deposition of ionic and particulate matter on wetted surfaces at
condensed portion of the steam along with the vapor. If the
specific flow rates (1-5).
sample tubing has too small an inside diameter, the pressure
5.1.1 To ensure that the physical and chemical properties of
drop may be excessive, reducing the quantity of sample
the sample are preserved, this flow rate must be controlled
available at the sample panel. In the case of super-heated
throughout the sampling process, regardless of expected
steam, significant ionic deposition can occur in the sample
changes of source temperature and pressure, for example,
tubing transport as the steam desuperheats. This can affect
during startup, or changing process operating conditions.
sample analysis accuracy significantly. Superheated samples
should use a process to inject cooled sample into the sample
5.2 The need to use analyzer temperature compensation
line at or near the nozzle outlet to desuperheat the sample so as
methods is dependent on the required accuracy of the measure-
to minimize deposition in the initial portion of the tubing run.
ment. Facilities dealing with ultra-pure water will require both
closely controlled sample temperature and temperature com-
6.4 Samples may become contaminated by products intro-
pensation to ensure accurate measurements. The temperature
duced into the stream by the tubing, valves, or other associated
canbecontrolledbyaddingasecondortrimcoolingstage.The
conditioning hardware. To minimize contamination of the
temperature compensation must be based on the specific
sample, high-grade tubing, such asType 316 SS, must be used.
contaminants in the sample being analyzed. In other facilities
Cobalt contamination from valve hardening material can intro-
in which some variation in water chemistry can be tolerated,
duce significant error in transition metal analysis by ion
the use of either trim cooling or accurate temperature compen-
chromatography.
sation may provide sufficient accuracy of process measure-
6.5 AirleakageintosamplelinescanaffectpH,conductivity
ments. This does not negate the highly recommended practice
(specific, cation, and degassed), and especially dissolved oxy-
of constant temperature sampling, especially at 25°C, as the
gen measurements.
most proven method of ensuring repeatable and comparable
analytical results.
6.6 The operation of a sample system includes periodically
taking grab samples and adding and removing on-line analyz-
5.3 A separate class of analysis exists that does not require
ers.Theaccuracyoftheanalysescanbeaffectediftheflowrate
or, in fact, cannot use the fully conditioned sample for accurate
through any on-line analyzer changes because of these proce-
results. For example, the collection of corrosion product
dures. The same is true if these actions change the flow rate in
samples requires that the sample remain at near full system
the incoming sample line to the system.
pressure, but cooled below the flash temperature, in order to
ensure a representative collection of particulates. Only some of
6.7 Changingthetemperatureofthesampleflowingthrough
theprimaryconditioningcriteriaapplyinthiscase,asinothers.
an on-line analyzer can alter the accuracy of the analysis.
Temperature compensation is not applicable since the material
Sample temperature can change because of a change in flow
being analyzed is not in a liquid state.
rate through the heat exchangers, because of a change of flow
rate of the cooling water in the heat exchangers, or from a
6. Interferences
change in temperature of the heat exchanger cooling water
6.1 Samples can be degraded by the loss of ionic or
supply. Every effort should be made to ensure constant sample
particulate components, introduction of contaminants by com-
temperature. The ideal sample temperature is 25 6 0.5°C
ponents or leaks, changes of sample flow rate through an
(77 6 1°F) because this is the standard for comparing readings
analyzer, excessively long sample lines, sample temperature
of temperature-sensitive analyses.
changes, and inaccurate temperature compensation of on-line
6.8 Electronic compensation is able to compensate for the
analysis equipment.
deviations in sample temperature for a known chemical matrix
(contamination). If an unknown source of contamination is
The boldface numbers in parentheses refer to a list of references at the end of
this standard. introduced, the analyzer may not be programmed, or
D5540 − 13 (2021)
programmable, to respond to the new solution. An error is and6.3.Keepthesamplelinesasshortaspossible(particularly
introduced as a result. The further the sample temperature steam)toeliminatealterationofthesamplepriortotheprimary
deviates from 25°C (77°F), the greater the error. cooling point.
8.1.2 Flow control of the sample streams involves two
6.9 In sliding pressure or c
...