Corrosion resistance tests are essential for the safe transportation of goods by sea. The aggressive saltwater environment places strict demands on materials and packaging. Various tests are mandatory for maritime transport, including the salt spray test, cyclic corrosion tests, and specific tests according to international standards such as ISO 9227 and ASTM B117. These tests ensure that materials and packaging can withstand the corrosive effects of seawater, allowing products to arrive safely at their destination without damage from corrosion.
Corrosion resistance tests are indispensable for seawater transport because seawater is extremely corrosive to most metals and materials. The high salt content (approximately 3.5% sodium chloride) significantly accelerates the corrosion process, which can lead to structural weakening, loss of function, and even complete damage to products during transport.
The economic impact of corrosion damage is enormous. Worldwide, corrosion costs billions of euros in damage annually, with a significant portion related to maritime transport. When products arrive damaged by corrosion, this leads not only to direct replacement costs but also to delays, production interruptions, and potential reputational damage.
For sectors such as defense and high-tech, protection against corrosion is even more important. Sensitive equipment, electronic components, and precision instruments can be rendered unusable by minimal corrosion. For defense equipment, reliability can literally be a matter of life and death, with corrosion damage being unacceptable.
Standardized tests provide a reliable method to predict how materials will behave under maritime conditions. They make it possible to:
By conducting corrosion resistance tests before products are shipped, you can proactively take protective measures and choose suitable packaging materials and methods that ensure the integrity of your products.
Various international standards prescribe corrosion resistance tests for maritime transport. These standards are important because they establish consistent test methods and assessment criteria, making results comparable and reliable. The most important standards are:
ISO 9227 – This standard specifies equipment, reagents, and procedures for salt spray tests, including:
ASTM B117 – The American standard for salt spray tests that is comparable to ISO 9227 but has specific differences in test parameters and procedures.
ISO 16701 – Specifies corrosion tests for simulating atmospheric corrosion under conditions with salt influence, relevant for maritime applications.
ISO 20340 – Performance requirements for protective paint systems for offshore and related structures.
For military applications, there are specific standards such as MIL-STD-810, which prescribe extensive tests for equipment that must function under extreme conditions, including maritime environments. This standard is particularly relevant for defense-related packaging and equipment that must withstand severe conditions.
In addition to these general standards, there are also sector-specific regulations:
It’s important to know which standard applies to your specific products and transport route. In some cases, multiple standards may apply, requiring compliance with the strictest requirements.
The salt spray test is one of the most commonly applied methods to evaluate the corrosion resistance of materials and packaging for seawater transport. This test simulates the corrosive environment of seawater under controlled laboratory conditions.
The basic principle of the test is simple: test samples are exposed to a fine mist of salt solution in a closed test chamber. The test procedure is as follows:
For transport packaging, the test duration varies depending on the application and standard, but typical test periods are:
The assessment criteria include:
For transport packaging exposed to seawater, minimum performance requirements include:
It’s important to note that the salt spray test only tests one aspect of corrosion resistance. For a complete assessment, multiple tests are often combined.
Cyclic corrosion tests are more complex and realistic tests than the standard salt spray test. They are required when transport means or packaging are exposed to varying environmental conditions, which is often the case with seawater transport. These tests simulate the alternation between different conditions such as salt spray, high humidity, dry periods, and temperature fluctuations.
Cyclic corrosion tests are specifically required in the following situations:
With extreme temperature fluctuations – When transport means cross different climate zones, for example from tropical to temperate or cold areas. The combination of temperature changes and salt exposure significantly accelerates corrosion processes. This is particularly relevant for international transports that cross multiple climate zones.
With prolonged exposure to maritime conditions – For transports that are en route for weeks or months, or for equipment used long-term in maritime environments. Think of containers that are at sea for months or defense equipment deployed on naval vessels.
For critical or high-value components – Electronic equipment, precision instruments, and other sensitive components often require cyclic tests to ensure their reliability under varying conditions. This applies particularly to defense and high-tech applications where reliability is crucial.
With combined loads – When materials are exposed not only to corrosion but also to mechanical stress, UV radiation, or chemical substances. The combination of these factors can accelerate or exacerbate corrosion.
A typical cyclic corrosion test consists of different phases that are repeated:
This cycle is repeated for periods of several days to weeks, depending on the required durability.
Standards that prescribe cyclic corrosion tests include:
For defense equipment, cyclic tests are often standard due to the extreme conditions under which this equipment must function.
Ignoring corrosion test regulations can have far-reaching legal, financial, and safety consequences. The main risks are:
Legal consequences – Non-compliance with mandatory tests can lead to:
Financial risks – The financial impact can be significant:
Safety risks – Especially with critical applications:
Insurance implications – Insurers may deny coverage if:
For international transports, customs authorities may stop or refuse goods if they do not comply with applicable corrosion resistance regulations. This is especially the case for goods subject to special regulations, such as dangerous substances or military equipment.
The most effective approach is preventive: ensure you are aware of the applicable regulations for your specific products and transport routes, and have the required tests performed in a timely manner by accredited test laboratories.
Performing the right corrosion resistance tests is not an unnecessary luxury but a necessary investment that protects your products during seawater transport. By understanding which tests are mandatory and why they are important, you can make informed decisions about materials, coatings, and packaging methods.
For critical applications in sectors such as defense, high-tech, and medical equipment, it is especially important to go beyond the minimum test requirements. Here, a comprehensive test program, including cyclic corrosion tests, can make the difference between success and costly failures.
At Faes, we understand the challenges of maritime transport and protecting valuable products against corrosion. With our expertise in industrial custom packaging, we can help you take the right protective measures to ensure your products arrive safely and in perfect condition at their destination – anywhere in the world.
The choice of the right test depends on factors such as the type of material, the expected transport duration, the route (which climate zones), and the sensitivity of your product to corrosion. For basic packaging, a standard salt spray test (NSS) according to ISO 9227 is often sufficient. For sensitive electronic components or products that are at sea for long periods, cyclic tests according to ISO 14993 are more suitable. Consult a specialized test laboratory for a customized test plan for your specific situation.
Common mistakes include: insufficient cleaning of test samples (which can distort results), testing non-representative samples, ignoring edges and joints where corrosion often begins, and insufficient documentation of the initial situation for comparison. Often, only material samples are tested rather than the complete packaging, while connection points and closures are particularly vulnerable to corrosion. Ensure thorough preparation and documentation of all test samples.
Laboratory tests are accelerated simulations that try to reproduce in days or weeks what actually takes months. They are standardized but cannot mimic all variables of real sea transports, such as movement, changing temperatures, or UV radiation. Cyclic corrosion tests come closest to reality. A rule of thumb is that 24-48 hours of salt spray testing corresponds to approximately 1-3 months in a moderate maritime environment, but this varies greatly by situation and material.
If your packaging does not meet requirements, you have multiple options: applying corrosion-resistant coatings (such as VCI coatings or special paints), using sacrificial laminates or anodes that corrode first, employing desiccants to absorb moisture, or using VCI paper or bags (Volatile Corrosion Inhibitors) that release corrosion inhibitors. For extreme conditions, you can also opt for completely sealed waterproof cases or containers with overpressure systems that keep moisture out.
