ASTM D6943-15(2019)

Standard Practice for Immersion Testing of Industrial Protective Coatings and Linings

SIGNIFICANCE AND USE
4.1 Protective coatings are used on metallic and concrete storage and processing vessels, shipping containers, dams and rail cars to protect the substrate from corrosive attack and to protect stored materials (cargo) from contamination. This method provides a means to assess the ability of a protective coating to resist degradation by chemicals and to protect the liquid cargo from contamination by either the substrate or coating, based on visual observations. Other measures of degradation, such as changes in weight or dimensions of the coating material, or chemical changes to the cargo, may be used to assess this protective ability as mutually agreed upon between contracting parties. Simple chemical-resistance evaluations of the lining materials may be performed more conveniently by other pertinent methods as a prescreening test for this procedure in accordance with Test Methods C267 and D471.  
4.2 This practice covers three approaches to conducting evaluations of a lining coating material’s fitness for purpose.  
4.2.1 Method A—Evaluation of specimens under conditions of constant temperature at atmospheric pressure (that is, without a thermal gradient).  
4.2.2 Method B—Evaluation of specimens under conditions which provide a temperature gradient across the sample.  
4.2.3 Method C—Evaluation of specimens under conditions of constant temperature and increased pressure (that is, without a thermal gradient).
SCOPE
1.1 This practice establishes procedures for the evaluation of the resistance of industrial protective coatings to immersion in chemicals.  
1.2 Linings are a particular type of coating intended for protection of substrates from corrosion as a result of continuous or intermittent fluid immersion.  
1.3 The values stated in SI units are to be regarded as the standard. The values given in parenthesis are for information only.  
1.4 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.  
1.5 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-Sep-2019
• ICS: 25.220.99 - Other treatments and coatings
• Technical Committee: D01 - Paint and Related Coatings, Materials, and Applications
• Drafting Committee: D01.46 - Industrial Protective Coatings

Relations

• Replaces: ASTM D6943-15 - Standard Practice for Immersion Testing of Industrial Protective Coatings and Linings
• Effective Date: 01-Oct-2019
• Replaces: ASTM C868-02(2012) - Standard Test Method for Chemical Resistance of Protective Linings (Withdrawn 2015)
• Effective Date: 04-Dec-2015
• Refers: ASTM D16-24 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jan-2024
• Refers: ASTM D4417-19 - Standard Test Methods for Field Measurement of Surface Profile of Blast Cleaned Steel
• Effective Date: 01-Dec-2019
• Refers: ASTM D6577-15(2019) - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 01-Oct-2019
• Refers: ASTM D7055-19 - Standard Practice for Preparation (by Abrasive Blast Cleaning) of Hot-Rolled Carbon Steel Panels for Testing of Coatings
• Effective Date: 01-Jun-2019
• Refers: ASTM D5139-19 - Standard Specification for Sample Preparation for Qualification Testing of Coatings to be Used in Nuclear Power Plants
• Effective Date: 01-Jun-2019
• Refers: ASTM D610-08(2019) - Standard Practice for Evaluating Degree of Rusting on Painted Steel Surfaces
• Effective Date: 01-Jan-2019
• Refers: ASTM D16-16 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Jul-2016
• Refers: ASTM D6577-15 - Standard Guide for Testing Industrial Protective Coatings
• Effective Date: 01-Dec-2015
• Refers: ASTM D16-14 - Standard Terminology for Paint, Related Coatings, Materials, and Applications
• Effective Date: 01-Dec-2014
• Refers: ASTM D7055-14 - Standard Practice for Preparation (by Abrasive Blast Cleaning) of Hot-Rolled Carbon Steel Panels for Testing of Coatings
• Effective Date: 01-Dec-2014
• Refers: ASTM G113-14 - Standard Terminology Relating to Natural and Artificial Weathering Tests of Nonmetallic Materials
• Effective Date: 01-Mar-2014
• Refers: ASTM D523-14 - Standard Test Method for Specular Gloss
• Effective Date: 01-Jan-2014
• Refers: ASTM D4538-13 - Standard Terminology Relating to Protective Coating and Lining Work for Power Generation Facilities
• Effective Date: 01-Nov-2013

Overview

ASTM D6943-15(2019) - Standard Practice for Immersion Testing of Industrial Protective Coatings and Linings establishes procedures for evaluating the resistance of protective coatings and linings to chemical immersion. Developed by ASTM International, this standard is specifically designed to assess coatings applied to metallic and concrete surfaces in environments such as storage tanks, shipping containers, dams, and railcars, where corrosion protection and cargo purity are critical. The practice helps determine a coating or lining’s ability to withstand chemical attack and to prevent contamination of stored materials by either the substrate or coating itself. Evaluations use visual inspection and, if agreed, physical or chemical measurements after exposure.

Key Topics

• Purpose and Scope: Defines test methods for assessing industrial coatings and linings exposed to corrosive chemicals, focusing on protection of substrates and cargo.
• Test Methods:
  • Method A: Immersion at constant temperature and atmospheric pressure (no thermal gradient).
  • Method B: Immersion with a deliberate temperature gradient across the sample.
  • Method C: Immersion at constant temperature under increased pressure (no thermal gradient).
• Substrate Types: Specifies tests for coatings on both metallic panels and cementitious panels, including detailed surface preparation.
• Measurement and Evaluation: Relies primarily on visual assessment of coating degradation, blistering, rusting, lifting, peeling, and other physical changes. Additional measures-such as changes in weight, thickness, or cargo chemistry-may be mutually agreed on.
• Test Specimen Preparation: Details substrate dimensions, surface profile requirements, application procedures, and film thickness checks. Holidays (coating continuity flaws) must be identified before testing.
• Test Chemicals and Conditions: Selection of chemicals mimics anticipated service conditions, with procedures agreed between involved parties.
• Inspection and Reporting: Periodic inspection and documentation throughout test duration, including unexposed reference sample comparison.

Applications

• Quality Assurance and Specification Compliance: Used by manufacturers, contractors, and asset owners to verify whether industrial protective coatings and linings meet specified chemical resistance requirements.
• Material Qualification: Assists in the selection of coatings or linings for chemical storage tanks, piping, railcars, and process vessels, ensuring long-term protection against aggressive chemicals and minimizing contamination risk.
• Comparative Analysis: Enables comparison among different protective coatings or lining systems for use in similar environments.
• Maintenance Planning: Provides data to plan coating maintenance cycles for infrastructure subjected to immersion or intermittent contact with harsh chemicals.
• Contractual Verification: Supports contractual obligations between suppliers and purchasers by documenting performance under standardized conditions.

Related Standards

ASTM D6943-15(2019) references, and is often used in conjunction with, several other international and industry standards for coatings and linings, including:

• ASTM C267 - Test Methods for Chemical Resistance of Mortars, Grouts, and Polymer Concretes
• ASTM D471 - Test Method for Rubber Property-Effect of Liquids
• ASTM D610, D714 - Visual Evaluation Methods for Paints and Coatings
• ASTM D7091, D6132 - Dry Film Thickness Measurement Procedures
• ASTM D3359, D4541, D7234 - Adhesion Testing
• NACE TM 0174 - Laboratory Methods for Evaluation of Protective Coatings in Immersion Service
• SSPC-SP5/NACE 1, SSPC-SP10/NACE 2, SSPC-SP13/NACE 6 - Surface Preparation Standards
• ASTM D4138, D4417 - Film Thickness and Surface Profile Testing Standards

Practical Value

Adherence to ASTM D6943-15(2019) ensures that protective coatings and linings for industrial applications can be reliably reviewed for performance in immersion service. Widespread acceptance of the standard fosters consistency, improves safety, extends asset life, and helps mitigate risks associated with chemical exposure. This practice is integral to industries such as petrochemical, transportation, water resources, and infrastructure maintenance, delivering tangible benefits in both regulatory compliance and operational reliability.

Keywords: industrial protective coatings, lining testing, immersion testing, chemical resistance, ASTM D6943, corrosion protection, substrate preparation, coating evaluation, quality assurance, industrial standards

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: D6943 − 15 (Reapproved 2019)
Standard Practice for
Immersion Testing of Industrial Protective Coatings and
Linings
This standard is issued under the fixed designation D6943; 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 D714 Test Method for Evaluating Degree of Blistering of
Paints
1.1 This practice establishes procedures for the evaluation
D785 Test Method for Rockwell Hardness of Plastics and
of the resistance of industrial protective coatings to immersion
Electrical Insulating Materials
in chemicals.
D1474 Test Methods for Indentation Hardness of Organic
1.2 Linings are a particular type of coating intended for
Coatings
protection of substrates from corrosion as a result of continu-
D1734 Practice for Making Cementitious Panels for Testing
ous or intermittent fluid immersion.
Coatings
1.3 The values stated in SI units are to be regarded as the
D2200 Practice for Use of Pictorial Surface Preparation
standard. The values given in parenthesis are for information
Standards and Guides for Painting Steel Surfaces
only.
D2240 Test Method for Rubber Property—Durometer Hard-
1.4 This standard does not purport to address all of the
ness
safety concerns, if any, associated with its use. It is the
D2583 Test Method for Indentation Hardness of Rigid Plas-
responsibility of the user of this standard to establish appro-
tics by Means of a Barcol Impressor
priate safety, health, and environmental practices and deter-
D3359 Test Methods for Rating Adhesion by Tape Test
mine the applicability of regulatory limitations prior to use.
D3363 Test Method for Film Hardness by Pencil Test
1.5 This international standard was developed in accor-
D4138 Practices for Measurement of Dry Film Thickness of
dance with internationally recognized principles on standard-
Protective Coating Systems by Destructive, Cross-
ization established in the Decision on Principles for the
Sectioning Means
Development of International Standards, Guides and Recom-
D4417 Test Methods for Field Measurement of Surface
mendations issued by the World Trade Organization Technical
Profile of Blast Cleaned Steel
Barriers to Trade (TBT) Committee.
D4538 Terminology Relating to Protective Coating and
2. Referenced Documents
Lining Work for Power Generation Facilities
D4541 Test Method for Pull-Off Strength of Coatings Using
2.1 ASTM Standards:
Portable Adhesion Testers
C267 Test Methods for Chemical Resistance of Mortars,
D5139 Specification for Sample Preparation for Qualifica-
Grouts,andMonolithicSurfacingsandPolymerConcretes
D16 TerminologyforPaint,RelatedCoatings,Materials,and tion Testing of Coatings to be Used in Nuclear Power
Applications Plants
D471 Test Method for Rubber Property—Effect of Liquids D5162 Practice for Discontinuity (Holiday) Testing of Non-
D523 Test Method for Specular Gloss conductive Protective Coating on Metallic Substrates
D610 Practice for Evaluating Degree of Rusting on Painted
D6132 TestMethodforNondestructiveMeasurementofDry
Steel Surfaces
Film Thickness of Applied Organic Coatings Using an
Ultrasonic Coating Thickness Gage
D6577 Guide for Testing Industrial Protective Coatings
This practice is under the jurisdiction of ASTM Committee D01 on Paint and
Related Coatings, Materials, and Applications and is the direct responsibility of D6677 Test Method for Evaluating Adhesion by Knife
Subcommittee D01.46 on Industrial Protective Coatings.
D7055 PracticeforPreparation(byAbrasiveBlastCleaning)
Current edition approved Oct. 1, 2019. Published October 2019. Originally
of Hot-Rolled Carbon Steel Panels forTesting of Coatings
approved in 2003. Last previous edition approved in 2015 as D6943 – 15. DOI:
10.1520/D6943-15R19. D7091 Practice for Nondestructive Measurement of Dry
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Film Thickness of Nonmagnetic Coatings Applied to
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Ferrous Metals and Nonmagnetic, Nonconductive Coat-
Standards volume information, refer to the standard’s Document Summary page on
theASTM website. ings Applied to Non-Ferrous Metals
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6943 − 15 (2019)
D7234 Test Method for Pull-OffAdhesion Strength of Coat- 5.1.1 Usecarbonsteelpanelswithaminimumtestsizeof50
ings on Concrete Using Portable Pull-Off Adhesion Tes- by 100 mm (2 by 4 in.), minimum thickness 3 mm ( ⁄8 in.),
ters unless otherwise agreed upon by purchaser and supplier.
G113 Terminology Relating to Natural andArtificial Weath-
NOTE 1—Test plates with a minimum width of 25 mm (1 in.) may be
ering Tests of Nonmetallic Materials
used if the film thickness is sufficiently uniform to prevent edge effects.
2.2 NACE Standard:
5.1.2 Usenominal4.8mm( ⁄16in.)thickcarbonsteelpanels
TM 0174-2002 Laboratory Methods for the Evaluation of
in coating tests if a temperature gradient is included in the
Protective Coatings and Lining Materials on Metallic
immersiontest,unlessotherwiseagreeduponbypurchaserand
Substrates in Immersion Service
supplier.
2.3 SSPC/NACE Joint Standards:
5.1.3 The minimum surface preparation is abrasive blast
SSPC-SP5/NACE 1 White Metal Blast Cleaning
cleaning to Near-White Metal condition as defined by Practice
SSPC-SP10/NACE 2 Near White Blast Cleaning
D2200 and by SSPC-SP10/NACE 2. The abrasive and feed
SSPC-SP13/NACE 6 Surface Preparation of Concrete
pressure shall be selected to produce an anchor pattern, which
SSPC Protective Coatings Glossary
is compatible with the coating system and acceptable to the
2.4 Other Document:
coating manufacturer.
Coating Encyclopedia Dictionary
5.1.4 Unless otherwise specified or agreed upon by pur-
chaser and seller, surface preparation shall be “White Metal
3. Terminology
Blast Cleaning” according to SSPC-SP5/NACE 1,withsurface
3.1 The definitions given in Terminologies D16, G113 and
profile of 35 to 90 micrometers (1.5 to 3.5 mils) as determined
D4538 are applicable to this practice.
by Method C of Test Methods D4417. If the product recom-
mendation falls outside of the range of Test Methods D4417
4. Significance and Use
thenpreparethetestpanelsinaccordancewithPracticeD7055.
4.1 Protective coatings are used on metallic and concrete 5.1.5 Othermetallicsubstrates,paneldimensions,orsurface
storage and processing vessels, shipping containers, dams and
preparation are acceptable if agreeable to concerned parties.
rail cars to protect the substrate from corrosive attack and to
5.2 Concrete and Cementitious Panels:
protect stored materials (cargo) from contamination. This
5.2.1 Cementitious Panels—The minimum panel size is 50
method provides a means to assess the ability of a protective
by 100 by 12 mm (2 by 4 by ⁄2 in.). Prepare cementitious
coating to resist degradation by chemicals and to protect the
panels by abrasive blast cleaning in accordance with SSPC-
liquid cargo from contamination by either the substrate or
SP13/NACE 6 or by other method agreed upon between
coating, based on visual observations. Other measures of
purchaser and supplier.
degradation, such as changes in weight or dimensions of the
5.2.2 Concrete Blocks—Form, condition and prepare con-
coating material, or chemical changes to the cargo, may be
crete blocks in accordance with the protocol described in
used to assess this protective ability as mutually agreed upon
Specifications D5139 or D1734. Prepare concrete blocks by
between contracting parties. Simple chemical-resistance evalu-
abrasive blast cleaning in accordance with SSPC-SP13/NACE
ations of the lining materials may be performed more conve-
6 or by other method agreed upon between purchaser and
niently by other pertinent methods as a prescreening test for
supplier.
this procedure in accordance with Test Methods C267 and
5.3 Coating Application:
D471.
5.3.1 For panels to be fully immersed, apply the coating
4.2 This practice covers three approaches to conducting
system to all test panel surfaces that will be subjected to
evaluations of a lining coating material’s fitness for purpose.
exposure.
4.2.1 Method A—Evaluation of specimens under conditions
5.3.2 Apply the coating system according to the manufac-
of constant temperature at atmospheric pressure (that is,
turer’s instructions appropriate for actual or anticipated service
without a thermal gradient).
conditions. Edges should be protected unless the intent of the
4.2.2 Method B—Evaluation of specimens under conditions
experiment is to evaluate the performance of the coating on
which provide a temperature gradient across the sample.
edges. For coatings to be tested under Method A (immersion
4.2.3 Method C—Evaluation of specimens under conditions
with no temperature gradient) or Method C (immersion at high
ofconstanttemperatureandincreasedpressure(thatis,without
pressure), apply the candidate coating to the back of the panel
a thermal gradient).
in addition to the front and the edges to prevent effects from
dissimilar coatings.
5. Preparation of Test Specimens
5.3.3 Dry film thickness of the coating shall be agreed upon
5.1 Metallic Panels:
between purchaser and seller.
5.3.3.1 Measure dry film thickness of coating applied to
metal surfaces in accordance with Practice D7091.
Available from NACE International (NACE), 1440 South Creek Dr., Houston,
TX 77084-4906, http://www.nace.org.
5.3.3.2 Measure dry film thickness of linings applied to
Available from Society for Protective Coatings (SSPC), 40 24th St., 6th Floor,
concrete or cementitious surfaces in accordance with Test
Pittsburgh, PA 15222-4656, http://www.sspc.org.
Method D6132. Alternative 1, measure dry film thickness of
Available from Federation of Societies for Coatings Technology (FSCT), 492
Norristown Rd., Blue Bell, PA 19422-2350, http://www.coatingstech.org. linings applied to concrete or cementitious surfaces by using
D6943 − 15 (2019)
sacrificial surfaces prepared concurrently with test specimens For elevated temperature immersion, an apparatus as described
in accordance with Practices D4138.Asecond alternative is to in NACE TM 0174-2002, Procedure B, is recommended.
simultaneously prepare a steel panel, placed next to one of the 7.1.2 Test Medium—The test solution is selected to corre-
concrete panels, and then measure its DFT in accordance with spond with the anticipated service of the coating. Add enough
2 3
Practice D7091. of the fluid to immerse ⁄3 to ⁄4 of the test panel.The fluid level
5.3.4 Examinethecoatedsurfaceforholidaysinaccordance should be checked at least once every 7 days. If more than 5 %
with Practice D5162. For test plates and concrete blocks, no of the test fluid evaporates from the test vessel, add enough
holidays are acceptable unless agreed upon between purchaser fluid to maintain the level and composition of the fluid.
and seller.
NOTE 5—When solvent or water evaporates, ensure that the addition
results in the same concentration as at the start of the test.
NOTE 2—High-voltage holiday detection should not be used on linings
that have been exposed. The test could be destructive and may not be
7.1.3 Test Procedure—Maintain a temperature of 25 6
...