Lab Tests Confirm Study Findings

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For Immediate Release
8 September 2020

The IICL released the findings of its study on coatings systems on frames of refrigerated containers on 28 May 2020. The study was then followed by laboratory tests with the objective to compare the performance of the coatings system in controlled environment and under the exact same conditions. Identical samples were treated with hot zinc spray and similar samples coated with zinc rich primer.

All samples for testing were prepared at a refrigerated container factory under the full supervision of our inspectors during a reefer production. Samples were properly collected, recorded, sealed, and sent to the laboratory for testing.

The identical samples were submitted to tests by impact, bending, and scribe followed by 500 hours exposure of salt spray and subsequently by an adhesion test. Relevant data and test information are presented on the enclosed laboratory test report.

As anticipated, the hot zinc spray coating system outperformed the zinc primer system in every test category. Also noticeable on all of the photos after 500 hours of salt spray is the fact that the zinc primer samples were found to have bleeding, running corrosion while the hot zinc spray samples look very good (except for some zinc salting and light corrosion on the bend test sample, and some very minor blistering on the scribe test.

According to the IICL’s Technical Director, Luiz Gonçalves, “the laboratory results confirmed what we have known for years in the industry. The hot zinc spray coating system is a critical factor to protect corten steel frames and prevent corrosion on reefer equipment. The results are clear and speak for themselves, samples coated with hot zinc spray outperformed others in all tests.”

The IICL continues to research and study this important issue. Additional comparison tests using samples coated with waterborne paint are being planned. We will provide you with new updates as they become available.

Luiz Gonçalves added, “we shared our findings with the China Container Industry Association - CCIA as we understand they are also conducting studies in this area and we look forward working with them to ensure refrigerated containers are built with high standards available in the industry”.

The laboratory test results and copy of our 28 May 2020 study are available at the links below.

For any questions or concerns regarding this press release please email


The IICL is active in educational, technological, safety, environmental, governmental, regulatory, and security issues. Complementing its widely accepted industry standards and best practices, the IICL offers its inspector certification examinations in more than 5,000 locations around the world, supported by publications, tools and courses.

Organized in 1971, the IICL is a trade association, representing lessors of maritime containers and intermodal chassis. Its member companies, Beacon, CAI, Direct ChassisLink, FlexiVan, SeaCube, Textainer, TOUAX, TRAC Intermodal, and Triton International Limited, own or manage a significant portion of the global leased container and U.S. chassis fleets.