Protecting Cargo with Container Desiccants

In our globalised economy, shipping containers play a vital role in transporting goods across long distances. One of the biggest challenges in this process is protecting cargo from moisture and humidity. If left unmanaged, these elements can cause significant damage to goods, resulting in financial loss, delivery delays and reputational harm.

Desiccants are highly effective materials that absorb moisture, offering a simple yet powerful way to reduce these risks. In this article, we explore how desiccants safeguard cargo and why they’re an essential element of shipping logistics and loss prevention.

What Are Desiccants?
Desiccants are substances designed to absorb or adsorb moisture, reducing humidity levels within enclosed spaces such as shipping containers. You’ve probably come across small sachets of silica gel marked “Do Not Eat” in items like shoes or electronics. However, desiccants come in many other forms and are used on a much larger scale in shipping.

Depending on the application, desiccants may take the form of sachets, strips, blankets, poles, or bulk bags.

Common Types of Desiccant Include:

• Silica Gel – Non-toxic and suitable for sensitive products like food and medicine, capable of adsorbing around 40% of its weight in moisture.

• Montmorillonite Clay – A natural and environmentally friendly moisture absorber derived from clay.

• Calcium Chloride – Extremely efficient, absorbing up to 300% of its own weight in moisture.

• Activated Carbon – Provides the added benefit of odour control alongside moisture absorption.

The Moisture Risk Inside Shipping Containers
Shipping containers are subject to dramatic environmental changes—crossing different climates and seasons—especially on long-haul sea routes. This can lead to condensation forming inside containers, commonly known as “container rain”. This happens when internal air cools and water vapour condenses on the ceiling and walls, then drips down onto cargo.

Condensation can result in mould, corrosion, staining, or the spoilage of goods, particularly sensitive items like electronics, textiles, or pharmaceuticals.

Why Use Desiccants in Containers?
Desiccants help prevent container rain by maintaining low humidity levels, absorbing moisture before it has a chance to condense. This is crucial for avoiding:

• Electrical faults or rust in machinery

• Mould or discolouration in textiles and packaging

• Spoilage in foods and pharmaceuticals

• Damage to the containers themselves, which can also corrode over time

These packs are low-cost, easy to install and highly effective—reducing losses, operational costs, and the likelihood of total consignment damage.

Choosing the Right Desiccant
Selection depends on several key factors:

• Cargo type – Pharmaceuticals may need food-grade desiccants like silica gel.

• Journey duration – Longer transits may require calcium chloride for its higher absorption capacity.

• Environmental conditions – Account for expected humidity and temperature changes.

Why Calcium Chloride Is a Popular Choice
Calcium chloride desiccants have become a leading solution due to their:

• High absorption rate – Up to 300% of their weight in water, compared to 30–40% for silica gel

• Leak-proof design – Moisture is typically locked into a gel to prevent re-release

• Versatility – Available in strips, poles, or hanging packs that don’t take up cargo space

• Effectiveness across climates – Performs reliably in both hot and cold conditions

• Safety – Non-toxic when used properly, though it can irritate the eyes if exposed

How It Works
Calcium chloride is hygroscopic—it attracts and absorbs moisture. The absorbed water forms a brine, which is then bound into a gel using additives like modified starch. This prevents any risk of leaking inside the container.

Applications Across Industries
Calcium chloride desiccants are widely used in:

• Electronics

• Machinery

• Food

• Pharmaceuticals

• Textiles

• Long-term warehouse storage

Their use is not limited to shipping containers. They’re also ideal for warehouses, basements, or storage units.

Best Practices for Placement

• Place near the roof, where condensation is most likely to occur

• Use hooks or lashing points to secure hanging desiccants without encroaching on cargo space

• Allow airflow around the desiccants—at least 2cm clearance

• Use the correct dosage for the container size and expected conditions

Suggested Dosage Per Container

These figures are only a guide—actual needs will depend on cargo type, moisture content, and environmental factors during transit. When shipping a new product or entering new markets, it’s advisable to err on the side of using more desiccant than not enough.

In Summary
Container desiccants are a vital tool in protecting goods during transport. They help mitigate the risks of condensation, reduce costs from damage or delays, and support customer satisfaction by ensuring goods arrive in top condition.

For those looking to optimise their shipping operations and reduce the risk of loss, investing in the right desiccant is a smart and cost-effective decision. At Universeal UK, we’re here to help you find the best moisture control solution for your cargo—whatever the challenge.

For more information on Protecting Cargo with Container Desiccants talk to Universeal (UK) Ltd