Moisture and condensation can cause corrosion and affect the reliability of military equipment. Suitable materials, VCI, desiccants and barrier packaging help control moisture and corrosion effectively. Relevant MIL-STD standards and targeted testing help keep packaging suitable for transport, storage and deployment.
Summary of this article
Corrosion in military packaging is prevented by applying a combination of moisture barriers, corrosion-inhibiting materials, and standardized protection techniques such as VCI film and desiccants. The most effective combination depends on the type of equipment, environmental conditions, and applicable MIL-STD standards. In this article, we answer the most frequently asked questions about corrosion prevention in military packaging, from material selection to testing methods.
The best corrosion protection in humid conditions is achieved through a combination of stainless steel or anodized aluminum for the packaging structure, VCI film as the inner barrier, and moisture-absorbing desiccants as supplementary protection. Together, these materials form a layered system that combats moisture at multiple levels.
For the outer packaging, materials such as HDPE plastic, fiberglass-reinforced polyester, and welded aluminum are popular choices. They withstand rain, condensation, and high humidity while simultaneously providing mechanical protection. Wooden crates are still used but require proper treatment and sealing to prevent moisture absorption.
Inside the packaging, material selection is equally important. Polyethylene or polyurethane foam interiors provide not only mechanical protection but can also be combined with VCI-treated materials. Stainless steel fasteners and closures prevent corrosion from reaching the product through hardware. Every material inside the packaging that comes into contact with the equipment deserves attention, as even small amounts of moisture or acid upon contact can cause damage to sensitive electronic or mechanical components.
The most common causes of corrosion in military equipment are condensation from temperature fluctuations, exposure to salt water or salt air, inadequate packaging seals, and the use of materials that cause galvanic corrosion. In operational environments, condensation is the biggest culprit.
When military equipment is transferred from a cold environment to a warm one, moisture condenses on metal surfaces. This phenomenon, also known as “sweating,” occurs even when the packaging appears to arrive dry. Maritime and coastal transport add salt to the equation, which significantly accelerates the corrosion process.
Galvanic corrosion is a less visible but serious problem. It occurs when two dissimilar metals come into contact in the presence of an electrolyte such as humid air. In packaging with mixed metals — such as aluminum frames with steel fasteners — this can lead to unexpected degradation of components.
Other common causes include:
The most relevant MIL-STD standards for moisture-resistant military packaging are MIL-PRF-131 for barrier materials, MIL-D-3464 for desiccants, and MIL-P-116 for packaging and preservation methods. These standards define the minimum requirements for protection against moisture, corrosion, and environmental influences.
MIL-PRF-131 specifies the performance requirements for barrier materials used to protect military equipment. It describes water vapor permeability, mechanical strength, and resistance to chemical substances. Materials that comply with this standard are suitable for packaging equipment stored for extended periods in humid or extreme conditions.
MIL-P-116 is an overarching standard that describes methods for preserving, packaging, and packing military goods. It distinguishes between different levels of protection, ranging from basic protection for short-term transport to comprehensive preservation for long-term storage in tropical conditions.
Packaging tested for moisture resistance is subject to additional test standards such as MIL-STD-810, which simulates environmental stress conditions including humidity, temperature fluctuations, and salt fog. Knowledge of these standards is essential when designing packaging for sensitive military equipment such as communication systems, drones, and optical instruments.
VCI (Volatile Corrosion Inhibitor) packaging works by releasing chemical compounds that evaporate from the packaging material and deposit on metal surfaces as an invisible protective layer. This layer blocks the electrochemical reactions that cause corrosion. VCI is the right choice for metal components that cannot be coated or oiled.
VCI materials are available in various forms: film, bags, paper, foam padding, and even emitters placed inside existing packaging. The active substances evaporate at room temperature and reach every metal surface within the sealed packaging, including hard-to-reach corners and internal components.
VCI is particularly effective for complex metal parts with large surface areas, electronic assemblies with exposed metal, and equipment that is frequently packed and unpacked. The protection is reversible: once the packaging is opened, the inhibitor layer evaporates without leaving residues on the equipment. This makes VCI ideal for mission-critical defense equipment that must be operationally ready for immediate use.
VCI is less effective in packaging that is not sufficiently sealed, as the active substances evaporate too quickly. It also provides no protection for non-metallic materials. In such cases, a combination with barrier packaging or desiccants is the better choice. Always verify that the VCI formulation is compatible with the specific metals in the equipment, as some inhibitors are not suitable for zinc, copper, or magnesium.
Desiccants actively absorb moisture from the air inside the packaging, while barrier packaging prevents moisture from entering the package from the outside. Both methods are complementary: a barrier keeps moisture out, while a desiccant neutralizes any residual moisture already present or that seeps in.
Desiccants such as silica gel, molecular sieves, and calcium chloride absorb water vapor from the enclosed air. They are used when packaging cannot be completely hermetically sealed, or when equipment is stored in environments with widely fluctuating temperatures. According to MIL-D-3464, desiccants are classified in units based on their absorption capacity, allowing the correct quantity per packaging volume to be calculated. Desiccants must be periodically replaced or regenerated during long-term storage.
Barrier packaging is made from materials with low water vapor permeability, such as laminated aluminum foil or multi-layer plastic films. It hermetically seals the equipment from the external environment. This is the most effective method for long-term storage or overseas transport. The drawback is that barrier packaging can be damaged by sharp edges or mechanical stress, causing the seal to fail. Always combine barrier packaging with a visual integrity check before use.
Military packaging is tested for moisture resistance by conducting standardized environmental tests in accordance with MIL-STD-810, during which the packaging is exposed to high humidity, temperature cycles, and salt fog. Additionally, sealing integrity is verified using pressure or vacuum tests, and the residual humidity inside the packaging is measured with a hygrometer.
The most commonly used test methods are:
In addition to laboratory tests, a visual inspection of foam interiors, sealing gaskets, and closures after each test is essential. Aging of rubber and foam can significantly reduce protection, even when the packaging appears undamaged from the outside.
Robert Verboven is Sales Manager at Faes and advises customers on smart packaging solutions within the industry. He translates complex packaging needs into practical solutions that contribute to a more efficient supply chain.
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