ASTM D3923-23

Standard Practices for Detecting Leaks in Reverse Osmosis and Nanofiltration Devices

SIGNIFICANCE AND USE
5.1 These practices may be used to determine whether a RO or NF device is free of leaks if the mechanical integrity of the device is to be confirmed. They may also be used to detect leaks in RO or NF devices whose operating performance indicates a possible leak. These practices may be used for either new or used devices.
SCOPE
1.1 These practices cover detecting leaks in which there is a direct communication between the feed or concentrate, or both, and the permeate. Several types of leaks are possible with the various configurations of reverse-osmosis (RO) and nanofiltration (NF) devices.  
1.2 Types of Leaks:  
1.2.1 With hollow-fiber devices, feed or concentrate leakage, or both, into the permeate stream by leaks through the tube sheet and past the tube sheet O-ring are possible. “Leaks” caused by broken fibers are not covered by these practices.  
1.2.2 With spiral-wound devices, leaks may occur through damage of the membrane surface itself by punctures or scratches, by glue-line failure, and by O-ring leaks on product tube interconnectors.  
1.2.3 With tubular devices, leaks due to membrane damage, tube end seal leaks, and leaks from broken tubes or product headers are possible.  
1.3 Three leak test practices are given as follows:    
Sections  
Practice A—Tube Sheet and O-Ring Leak Test for Hollow
Fiber Devices  
8 to 9  
Practice B—Vacuum Test for Spiral Wound Devices  
10 to 12  
Practice C—Dye Test for Spiral Wound and Tubular Devices  
13 to 18  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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: 31-Dec-2022
• ICS: 71.120.99 - Other equipment for the chemical industry
• Technical Committee: D19 - Water
• Drafting Committee: D19.08 - Membranes and Ion Exchange Materials

Relations

• Refers: ASTM D1129-13(2020)e2 - Standard Terminology Relating to Water
• Effective Date: 01-May-2020
• Refers: ASTM D6161-19 - Standard Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes
• Effective Date: 01-Jul-2019
• Refers: ASTM D6908-06(2017) - Standard Practice for Integrity Testing of Water Filtration Membrane Systems
• Effective Date: 01-Dec-2017
• Refers: ASTM D6908-06(2010) - Standard Practice for Integrity Testing of Water Filtration Membrane Systems
• Effective Date: 01-May-2010
• Refers: ASTM D1129-10 - Standard Terminology Relating to Water
• Effective Date: 01-Mar-2010
• Refers: ASTM D6161-10 - Standard Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration and Reverse Osmosis Membrane Processes (Withdrawn 2019)
• Effective Date: 01-Feb-2010
• Refers: ASTM E275-08 - Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
• Effective Date: 15-Oct-2008
• Refers: ASTM D4194-03(2008) - Standard Test Methods for Operating Characteristics of Reverse Osmosis and Nanofiltration Devices
• Effective Date: 01-May-2008
• Refers: ASTM D1129-06ae1 - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D1129-06a - Standard Terminology Relating to Water
• Effective Date: 01-Sep-2006
• Refers: ASTM D6908-06 - Standard Practice for Integrity Testing of Water Filtration Membrane Systems
• Effective Date: 01-Jul-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 D6908-05 - Standard Practice for Integrity Testing of Water Filtration Membrane Systems
• Effective Date: 01-Oct-2005
• Refers: ASTM D6161-05 - Standard Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration and Reverse Osmosis Membrane Processes
• Effective Date: 01-Jun-2005

Overview

ASTM D3923-23: Standard Practices for Detecting Leaks in Reverse Osmosis and Nanofiltration Devices sets out internationally recognized procedures for confirming the mechanical integrity and leak-tightness of reverse osmosis (RO) and nanofiltration (NF) systems. These practices focus on detecting direct communication (leakage) between the feed or concentrate and the permeate side in various types of membrane devices, including hollow-fiber, spiral-wound, and tubular modules.

Ensuring RO and NF systems are free from leaks is critical for reliable operation, water quality, and compliance with industry regulations. This standard provides clear testing methodologies for both new and used devices, making it valuable across installation, maintenance, or troubleshooting processes.

Key Topics

• Leak Types by Device Configuration:

  • Hollow-Fiber Devices: Leaks may occur through the tube sheet or past O-ring seals. Fiber breakage-related leaks are outside this standard's scope.
  • Spiral-Wound Devices: Potential leaks include punctures or scratches in the membrane, glue-line failures, or O-ring issues on product tube interconnectors.
  • Tubular Devices: Leaks can arise from membrane damage, tube end seal failures, or compromised headers.

• Test Practices Included:

  • Tube Sheet and O-Ring Leak Test for hollow-fiber devices
  • Vacuum Test for spiral-wound devices
  • Dye Test for spiral-wound and tubular devices

• SI Units Compliance: All measurements and references follow SI units as the international standard.

• User Safety: The standard reminds users to establish appropriate safety, health, and environmental practices, as well as to consider applicable regulatory constraints before usage.

Applications

Implementing ASTM D3923-23 practices is essential for a variety of professionals and industries, including water treatment plants, industrial water reuse, power generation, and facilities management. Typical applications include:

• Commissioning of New RO/NF Devices: Certifying leak-free operation before system start-up.
• Routine Maintenance: Verifying integrity of membranes and modules as part of periodic service schedules.
• Troubleshooting Performance Issues: Identifying suspected leaks causing drops in water purity or performance.
• Quality Assurance in Manufacturing: Ensuring that produced devices meet leak integrity specifications before shipment.

Regular application of the outlined leak detection tests helps prevent unforeseen system failures, supports compliance with water quality standards, and prolongs the lifespan of costly membrane elements.

Related Standards

Professionals using ASTM D3923-23 may also reference these associated ASTM standards to enhance water treatment system performance and compliance:

• ASTM D4194: Test Methods for Operating Characteristics of Reverse Osmosis and Nanofiltration Devices.
• ASTM D6908: Practice for Integrity Testing of Water Filtration Membrane Systems.
• ASTM D1193: Specification for Reagent Water.
• ASTM D1129/D6161: Terminologies relating to water and membrane processes.
• ASTM E60 & E275: Practices and methods for spectrophotometric analysis.

Summary

ASTM D3923-23 is a comprehensive and practical standard for detecting leaks in reverse osmosis and nanofiltration devices, focusing on methods tailored to device configuration and industry needs. Applying these practices supports operational reliability, ensures water quality, and underpins compliance with international water treatment standards.

For further technical detail or to ensure official compliance, consult the latest published version of the standard through ASTM International.

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: D3923 − 23
Standard Practices for
Detecting Leaks in Reverse Osmosis and Nanofiltration
Devices
This standard is issued under the fixed designation D3923; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 These practices cover detecting leaks in which there is a
direct communication between the feed or concentrate, or both,
2. Referenced Documents
and the permeate. Several types of leaks are possible with the
2.1 ASTM Standards:
various configurations of reverse-osmosis (RO) and nanofiltra-
D1129 Terminology Relating to Water
tion (NF) devices.
D1193 Specification for Reagent Water
1.2 Types of Leaks:
D4194 Test Methods for Operating Characteristics of Re-
1.2.1 With hollow-fiber devices, feed or concentrate
verse Osmosis and Nanofiltration Devices
leakage, or both, into the permeate stream by leaks through the
D6161 Terminology Used for Microfiltration, Ultrafiltration,
tube sheet and past the tube sheet O-ring are possible. “Leaks”
Nanofiltration, and Reverse Osmosis Membrane Processes
caused by broken fibers are not covered by these practices.
D6908 Practice for Integrity Testing of Water Filtration
1.2.2 With spiral-wound devices, leaks may occur through
Membrane Systems
damage of the membrane surface itself by punctures or
E60 Practice for Analysis of Metals, Ores, and Related
scratches, by glue-line failure, and by O-ring leaks on product
Materials by Spectrophotometry
tube interconnectors.
E275 Practice for Describing and Measuring Performance of
1.2.3 With tubular devices, leaks due to membrane damage,
Ultraviolet and Visible Spectrophotometers
tube end seal leaks, and leaks from broken tubes or product
headers are possible.
3. Terminology
1.3 Three leak test practices are given as follows:
3.1 Definitions:
Sections 3.1.1 For definitions of terms used in these practices, refer
Practice A—Tube Sheet and O-Ring Leak Test for Hollow 8 to 9
to Terminology D1129 and D6161.
Fiber Devices
3.1.2 concentrate, n—stream exiting a crossflow membrane
Practice B—Vacuum Test for Spiral Wound Devices 10 to 12
Practice C—Dye Test for Spiral Wound and Tubular Devices 13 to 18
device that has increased concentration of solutes and particles
over the feed stream; portion of the feed steram that does not
1.4 The values stated in SI units are to be regarded as
pass through the membrane; the stream in which dissolved
standard. No other units of measurement are included in this
solids or particulates, or both, are concentrated in a membrane
standard.
separation process.
1.5 This standard does not purport to address all of the
3.1.3 hollow-fiber (HF) membrane, n—self-supporting
safety concerns, if any, associated with its use. It is the
membrane fibers that have a hollow bore like a cylinder; in
responsibility of the user of this standard to establish appro-
reverse osmosis, the membrane is usually on the outside with
priate safety, health, and environmental practices and deter-
the bore conveying the permeate; in ultra and micro filtration,
mine the applicability of regulatory limitations prior to use.
the membrane might be on the inside or outside of the fiber.
1.6 This international standard was developed in accor-
dance with internationally recognized principles on standard-
3.1.4 leak, n—bypassing of the intact membrane from the
ization established in the Decision on Principles for the
feed side to the permeate side.
Development of International Standards, Guides and Recom-
3.1.5 nanofiltration (NF), n—crossflow process with pore
sizes designed to remove selected salts and most organics
These practices are under the jurisdiction of ASTM Committee D19 on Water
and are the direct responsibility of Subcommittee D19.08 on Membranes and Ion
Exchange Materials. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Jan. 1, 2023. Published February 2023. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 1980. Last previous edition approved in 2014 as D3923 – 08 (2014). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/D3923-23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3923 − 23
above about 300 molecular weight range, sometimes referred specifications are available. Other grades may be used,
to as loose RO; a pressure-driven membrane separation process provided it is first ascertained that the reagent is of sufficiently
in which particles and dissolved molecules larger than about high purity to permit its use without lessening the accuracy of
2 nm are rejected. the determinations.
3.1.6 permeate, n—that portion of the feed which passes 7.2 Unless otherwise indicated, references to water shall be
through the membrane. understood to mean Type III reagent water conforming to
Specification D1193.
3.1.7 reverse osmosis (RO), n—separation process in which
one component of a solution is removed from another compo-
PRACTICE A—TUBE SHEET AND O-RING LEAK
nent by flowing the feed stream under pressure across a
TEST FOR HOLLOW FIBER DEVICES
semipermeable membrane that causes selective movement of
solvent against its osmonic pressure difference; RO removes
8. Scope
ions based on electrochemical forces, colloids, and organics
8.1 This practice is applicable to detecting feed or concen-
down to 150 molecular weight; may also be called hyperfil-
trate leakage, or both, through the tube sheet and past the tube
tration.
sheet O-ring into the permeate in hollow-fiber devices.
3.1.8 spiral wound membrane, n—a flat sheet membrane
9. Procedure
with one or more feed channel spacers, and barrier layers, all
of which are rolled into a spiral configuration.
9.1 Drain the liquid from the feed side of the membrane.
3.1.9 tubular membrane, n—the element, similar to hollow-
9.2 Connect a centrifugal pump with 1.4 MPa (200 psig)
fiber but with a bore diameter >5 mm (see hollow-fiber); used
capability and a throttling valve to the feed port of the
mostly in MF and UF and sometimes wit RO and NF when
hollow-fiber device. Install a pressure gage and valve on the
particulate loading is high.
concentrate port of the RO or NF device.
9.3 Remove the permeate end plate and auxiliary equipment
4. Summary of Practice
in accordance with the supplier’s instructions to expose the
face of the permeate tube sheet.
4.1 The hollow-fiber device being tested is operated at low
pressure with the permeate tube sheet exposed (the fiber bundle
9.4 Install a “spider” device (available from supplier) de-
is held in place by a “spider” device designed for the specific
signed for the specific model under test and secure the “spider”
model under test). Any significant leak in the tube sheet or
with the snap or segmented ring that held the permeate end
O-ring seal is detected visually by inspection.
plate in place.
9.5 Place the hollow-fiber device in the horizontal position
5. Significance and Use
and orient the open concentrate line to the highest point (12
5.1 These practices may be used to determine whether a RO
o’clock). Allow water to flow through the device at line
or NF device is free of leaks if the mechanical integrity of the
pressure (approximately 350 kPa; 50 psig) to remove any
device is to be confirmed. They may also be used to detect
trapped air in the device. Slowly close concentrate line valve to
leaks in RO or NF devices whose operating performance
pressurize the unit to 350 kPa (50 psig). While standing clear
indicates a possible leak. These practices may be used for
of the tube sheet, start the pump and increase pressure slowly
either new or used devices.
until a maximum pressure of 1.05 MPa (150 psig) is obtained.
Proceed with the tube sheet inspection.
6. Apparatus
NOTE 1—The leak test should take approximately 15 min to determine
the integrity of the tube sheet and tube sheet O-ring.
6.1 “Spider” Device, designed for the specific model of
hollow-fiber device being tested, is available from the supplier.
9.6 Examine for leaks by observing the product water as it
The “spider” is designed to take the place of the permeate end
exits the tube sheet face. If leaks do not exist, the product water
pla
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D3923 − 08 (Reapproved 2014) D3923 − 23
Standard Practices for
Detecting Leaks in Reverse Osmosis and Nanofiltration
Devices
This standard is issued under the fixed designation D3923; 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
1.1 These practices cover detecting leaks in which there is a direct communication between the feed or concentrate, or both, and
the permeate. Several types of leaks are possible with the various configurations of reverse-osmosis (RO) and nanofiltration (NF)
devices.
1.2 Types of Leaks:
1.2.1 With hollow-fiber devices, feed or concentrate leakage, or both, into the permeate stream by leaks through the tube sheet
and past the tube sheet O-ring are possible. “Leaks” caused by broken fibers are not covered by these practices.
1.2.2 With spiral-wound devices, leaks may occur through damage of the membrane surface itself by punctures or scratches, by
glue-line failure, and by O-ring leaks on product tube interconnectors.
1.2.3 With tubular devices, leaks due to membrane damage, tube end seal leaks, and leaks from broken tubes or product headers
are possible.
1.3 Three leak test practices are given as follows:
Sections
Practice A—Tube Sheet and O-Ring Leak Test for Hollow 8 to 9
Fiber Devices
Practice B—Vacuum Test for Spiral Wound Devices 10 to 12
Practice C—Dye Test for Spiral Wound and Tubular Devices 13 to 18
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 and healthsafety, 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.
These practices are under the jurisdiction of ASTM Committee D19 on Water and are the direct responsibility of Subcommittee D19.08 on Membranes and Ion Exchange
Materials.
Current edition approved Jan. 1, 2014Jan. 1, 2023. Published February 2014February 2023. Originally approved in 1980. Last previous edition approved in 20082014 as
D3923 – 08.D3923 – 08 (2014). DOI: 10.1520/D3923-08R14.10.1520/D3923-23.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3923 − 23
2. Referenced Documents
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1193 Specification for Reagent Water
D4194 Test Methods for Operating Characteristics of Reverse Osmosis and Nanofiltration Devices
D6161 Terminology Used for Microfiltration, Ultrafiltration, Nanofiltration, and Reverse Osmosis Membrane Processes
D6908 Practice for Integrity Testing of Water Filtration Membrane Systems
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
E275 Practice for Describing and Measuring Performance of Ultraviolet and Visible Spectrophotometers
3. Terminology
3.1 For definitions of terms used in these practices, refer to Terminology D1129 and D6161.
3.1 Definitions of Terms Specific to This Standard:Definitions:
3.1.1 For definitions of terms used in these practices, refer to Terminology D1129 and D6161.
3.1.2 concentrate, n—stream exiting a crossflow membrane device that has increased concentration of solutes and particles over
the feed stream; portion of the feed steram that does not pass through the membrane; the stream in which dissolved solids or
particulates, or both, are concentrated in a membrane separation process.
3.1.3 hollow-fiber (HF) membrane, n—self-supporting membrane fibers that have a hollow bore like a cylinder; in reverse
osmosis, the membrane is usually on the outside with the bore conveying the permeate; in ultra and micro filtration, the membrane
might be on the inside or outside of the fiber.
3.1.4 leak—leak, n—bypassing of the intact membrane from the feed side to the permeate side.
3.1.5 nanofiltration (NF), n—crossflow process with pore sizes designed to remove selected salts and most organics above about
300 molecular weight range, sometimes referred to as loose RO; a pressure-driven membrane separation process in which particles
and dissolved molecules larger than about 2 nm are rejected.
3.1.6 permeate, n—that portion of the feed which passes through the membrane.
3.1.7 reverse osmosis (RO), n—separation process in which one component of a solution is removed from another component by
flowing the feed stream under pressure across a semipermeable membrane that causes selective movement of solvent against its
osmonic pressure difference; RO removes ions based on electrochemical forces, colloids, and organics down to 150 molecular
weight; may also be called hyperfiltration.
3.1.8 spiral wound membrane, n—a flat sheet membrane with one or more feed channel spacers, and barrier layers, all of which
are rolled into a spiral configuration.
3.1.9 tubular membrane, n—the element, similar to hollow-fiber but with a bore diameter >5 mm (see hollow-fiber); used mostly
in MF and UF and sometimes wit RO and NF when particulate loading is high.
4. Summary of Practice
4.1 The hollow-fiber device being tested is operated at low pressure with the permeate tube sheet exposed (the fiber bundle is held
in place by a “spider” device designed for the specific model under test). Any significant leak in the tube sheet or O-ring seal is
detected visually by inspection.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D3923 − 23
5. Significance and Use
5.1 These practices may be used to determine whether a RO or NF device is free of leaks if the mechanical integrity of the device
is to be confirmed. They may also be used to detect leaks in RO or NF devices whose operating performance indicates a possible
leak. These practices may be used for either new or used devices.
6. Apparatus
6.1 “Spider” Device, designed for the specific model of hollow-fiber device being tested, is available from the supplier. The
“spider” is designed to take the place of the permeate end plate and permeate collection grid/block while securing the fiber bundle
from movement. This allows visual observation during low-pressure operation with the fiber bundle retained in its original
position.
7. Purity of Reagents
7.1 Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all reagents shall conform
to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where such specifications are
available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purity to permit its use
without lessening the accuracy of the determinations.
7.2 Unless otherwise indicated, references to water shall be understood to mean Type III reagent water conforming to Specification
D1193.
PRACTICE A—TUBE SHEET AND O-RING LEAK TEST FOR HOLLOW FIBER DEVICES
8. Scope
8.1 This practice is applicable to detecting feed or concentrate leakage, or both, through the tube sheet and past the tube sheet
O-ring into the permeate in hollow-fiber devices.
9. Procedure
9.1 Drain the liquid from the feed side of the membrane.
9.2 Connect a centrifugal pump with 1.4 MPa (200 psig) capability and a throttling valve to the feed port of the hollow-fiber
device. Install a pressure gage and valve on the concentrate port of the RO or NF device.
9.3 Remove the permeate end plate and auxiliary equipment in accordance with the supplier’s instructions to expose the face of
the permeate tube sheet.
9.4 Install a “spider” device (available from supplier) designed for the specific model under test and secure the “spider” with the
snap or segmented ring that held the permeate end plate in place.
9.5 Place the hollow-fiber device in the horizontal position and orient the open concentrate line to the highest point (12 o’clock).
Allow water to flow through the device
...