ASTM D870 Standard Practice for Testing Water Resistance of Coatings Using Water Immersion

    ASTM D870 Introduction

    ASTM D870 (Standard for Testing Water Resistance of Coatings Using Water Immersion) is a widely accepted method, as water immersion can damage coatings and affect their service life. It predicts failures due to coating deficiencies, substrate contamination, or inadequate surface preparation. Water immersion tests aid in coatings and substrate treatment research, specification acceptance, and manufacturing quality control. It is used for research and quality control, and it determines pass/fail based on damage resistance over time. Accelerating corrosion processes like pitting, it helps engineers predict coating effectiveness before service.

    Read more

    Other test methods to evaluate water resistance include ASTM D1735 (water fog), ASTM D2247 (100% humidity), and ASTM D4585 (controlled condensation

    Get Certified ASTM D870 for Uncompromising Quality and Project Success

    ASTM D870 certification proves a laboratory can accurately measure coating water resistance through controlled immersion. It guarantees compliance with global standards, ensuring consistent results across manufacturers. By using this certified method, companies assess durability, identify weaknesses, and verify specifications. This certification boosts product reliability, market acceptance, and quality assurance.

    The images shows the equipment for water immersion testing by astm d870.
    Water Immersion Testing Equipment

    What is the Scope of ASTM D870?

    • Guides testing protocols to evaluate how well coatings withstand continuous water immersion.
    • Ensures reliable and uniform assessment of water-induced coating degradation.
    • Suited for both experimental research and industrial quality assurance applications.
    • Compatible with both manual and computerized environmental testing equipment.

    What is the equipment requirement and Sample Preparation for ASTM D870 

    Specimen DetailsA control specimen of paint with known durability is used in each test. Such control specimens reflect variations in test severity between several apparatuses and can signal changes in test severity in a specific apparatus. To account for variations among specimens and test conditions within the apparatus, at least two replicated specimens of each coating type are used.
    Substrate MaterialMetal (steel, aluminum), wood, or plastic panels, depending on coating type. Substrate must be compatible with the coating system.
    Specimen DimensionsCommon dimensions range from 75 × 150 mm to 100 × 150 mm, or as specified by the coating manufacturer. Panels must fit without touching tank walls or other specimens.

    What are the uses of ASTM D870

    • Testing of marine, industrial, and architectural protective coating. 

    Read more

    • Confirmation of the performance of corrosion protection. 

    • Clear coat, primer, and topcoat testing in the automotive and aerospace market. 

    • Studies of waterborne finishes and new protection compositions. 

    • Coating performance measurement under the humid, wet, or submerged conditions.

    What are the Common Challenges and Troubleshooting

    Uneven curing, temperature fluctuations, contaminated water, and incorrect exposure times often cause problems. Mishandling specimens after immersion can also distort results. To reduce variability, laboratories control the pre-test environment and prevent air bubbles. Using automated immersion tanks with temperature control, adhering to strict curing protocols, and replacing water regularly increases testing reliability.  Calibrated heaters and gauges maintain a consistent 35 °C in the salt spray chamber to ensure steady corrosion rates and reliable rust development. Standardized evaluation criteria and trained inspectors ensure consistent assessments of coating performance.

    Testing Technique, Process, and Data Collection

    Data collection involves documenting the frequency and intensity of defects using standardized rating scales. Photographic documentation and measurements of mass or dimensional shifts are recorded for comparison in evaluation. This data is essential for categorizing the performance of coatings and establishing a link between test results and anticipated environmental durability.

    What are the Testing Procedures and Requirements? 

    In the ASTM D870 testing procedure, coated specimens are immersed in water (distilled or saline) under controlled temperature conditions for a specified duration. Defects such as blistering, peeling, or corrosion are periodically inspected to assess coating performance.

    Read more

    Preparation of Coated PanelsApply coating uniformly on clean substrates; allow full curing; ensure consistent film thickness and defect-free surfaces.
    Water Immersion SetupImmerse panels fully in distilled/deionised water; maintain controlled temperature (25–38°C); ensure no trapped air bubbles.
    Exposure DurationKeep specimens submerged for the specified time (24 hours to several weeks), depending on coating performance requirements.

    Analysis Results and Interpretation

    ASTM D870 test shows how coatings respond to prolonged exposure to water immersion, identifying specific failures such as film softening, loss of adhesion, and osmotic blistering. Adequate interpretation depends on proper assessment of the severity of defects against established rating standards. These results serve as a critical justification for determining whether a coating is suitable for use in wet or submerged environments.

    Read more

    Direct link to PDF

    FAQ

    Where can I get the astm d870 tested?
    You can share your astm d870 testing requirements with MaTestLab. MaTestLab has a vast network of material testing laboratories, spread across the USA and Canada. We support your all material testing needs ranging from specific astm d870 test to various testing techniques.
    Please contact us for a detailed quote for your astm d870 testing needs. Cost incurred to carry out different astm d870 testing methodology depends on the type of raw material; number of samples, coupons, or specimens; test conditions, turn around time etc. Costs of some ASTM testing methods start from $100 and the final value depends upon the factors listed above. Please contact us for the best and latest prices.
    The required number of samples or specimens should comply with the procedure given in the astm d870 standard. However, the MaTestLab operations team can assist you for your special requirements once you share your testing details with us.
    MaTestLab has a vast testing laboratory network, hence we bring you the best testing facilities in a cost-effective way. We offer considerable discounts (15-20%) to our returning customers based on test volume and frequency.
    The turnaround time for astm d870 test methodology depends upon the test procedure mentioned in the standard test document. However, we at MaTestLab understand your research requirements and hence try to get your test completed within the least possible time.
    Gokula Srinivasan Selvam
    About Author
    Gokula Srinivasan Selvam
    Gokula Srinivasan Selvam is a Material Testing Associate at MaTestLab Inc. and holds a postgraduate degree in Ceramic Engineering from IIT (BHU), Varanasi.
    Testimonials
    Real results
    Engineers trust us with what matters most
    Start Your Testing
    Project Today
    Define your requirements and get access to
    specialized laboratories ready to deliver results
    Start Testing
    Contact us
    Partners with us
    Clients
    Vendors
    Process for testing
    • STEP 01

      You share your testing requirements

    • STEP 02

      You share your sample(s)

    • STEP 03

      We deliver your test reports

    Get your testing done

    Let us known your testing requirements and we will be right back with a solution.

      Let us root for each other. Collaborate to grow, expand, and accelerate our businesses.

      Partner with us

        Contact Us

        Discover more from MaTestLab

        Subscribe now to keep reading and get access to the full archive.

        Continue reading