A container is exposed to temperature and humidity differences during a sea voyage. This creates condensation and causes damage to cargo, damage ranging from rust, corrosion and mould to warping labels. Container Drybags™ have been developed to systematically absorb moisture during a long sea voyage up to 120 days, which means that the container desiccants interrupt the condensation process, so that cargo is well protected against moisture damage.

Shipping cargo in containers is generally the cheapest and safest way to transport most types of cargo. However, transporting cargo in a container is associated with a high risk of moisture damage. To be precise, almost 50% of all transport in containers worldwide faces moisture damage.

We like to inform you about what is exactly happening and what you can do to limit risks. In order to explain what happens in the container during a sea voyage, we make a distinction between the container itself and the cargo to be transported.

The container

A container is made of steel, the only openings in a container are the doors and the ventilation holes. In addition, most containers have a wooden floor. The doors are fitted with rubbers to counteract outside influences, but a complete air seal will never take place. As a result, there is always air circulating which retains a certain amount of moisture per cubic meter. We call this process container breathing. A well-closing container will entail a limited risk, it is therefore important that you inspect the container properly to avoid unnecessary risks.

You do not want remnants from a previous transport to potentially cause contamination. For this reason, a shipping company has a duty to clean the containers prior to delivery. The container is cleaned with a lot of high-pressure water, the wooden floor absorb the water like a sponge. We advise to use a dry as possible container and inspect the floor beforehand. Our advice is to load when the humidity of the floor is less than 15% with a maximum of 20%, but not above.

The more water inside the container the more risk of damages. The fact is that warm air can hold more moisture than cold air. When the temperature drops, the air becomes more humid. With sufficient cooling, some of the moisture can condense. A rapid but very minimal temperature drop is often enough to cause problems. Water will condense on the ceiling and walls of the container as these are the coolest surfaces. We call the droplets container rain which cause damage to your load.

The cargo to be transported

We distinguish two types of goods, namely: dry goods and moist goods.

With dry goods, it is important that the packaging is optimally adapted to the conditions during transport. To keep goods perfectly dry, a sturdy, airtight and waterproof packaging is required. However, even with a good packaging method it may be desirable to remove moisture from the outside, packaging may accidentally not be properly closed or be part of the product itself. An example is powder which starts to cake despite the good packaging.

A lot of cargo already contains a certain moisture percentage, such as cocoa or coffee beans. With moist cargo, it is important that the packaging is optimally adapted to the conditions during transport. In practice, we see that such products are often packed in an air-permeable bag. Especially in this situation it is very important to ensure that moisture is removed with container desiccants to avoid mould.

Limiting risks to possible elimination

Damage due to moisture is one of the biggest problems during container transports, moisture damage is very unpredictable, and it is often difficult to trace without an expert’s eye.

Humidity changes due to temperature differences. The fluctuations during the day and night temperatures and weather changes cause condensation in the container. When the air becomes cooler at night or after stormy colder weather, it becomes more humid, even though the moisture content in the air remains the same. If a temperature changes very quickly, condensation occurs and the risk of moisture arising and affecting your cargo is enormous.

Our aim is to have your transports arrive safely; we do this by carefully looking at all facets in the process without obligation and free of charge to give you optimal and efficient – and above all cost-saving – advice. We design and produce container desiccants, and because of our diverse range we can also assist with your packaging question or your load securing tasks if required.

We work with the following basic principles from which we can give you solid advice with our many years of practical experience;

• Which products are being transported, are they dry or moist in nature?
• Does the packaging of the load meet the requirements?
• What are the weather conditions like when loading the container?
• Is the container in good technical condition?
• Is the container airtight and are all materials including the floor and dunnage dry enough?
• Which route does a ship sail and are stops made?
• What is the positioning of a container on a ship (below or above deck?)
• Temperature differences and the relative humidity.
• Have deviating circumstances been observed during a transport, including the duration of a shipment.