Each year, countless tons of cargo are stored and transported across the globe in a variety of shipping container types. In 2013, the international liner shipping industry transported around 120 million containers, filled with approximately $4 trillion worth of cargo. With so many goods making their way across the globe’s oceans each year, shipping companies are tasked with safely transporting cargo, ensuring it gets to its final destination unscathed.
Unfortunately, companies face a rather large hurdle in their transportation efforts: shipping container condensation. Moisture damage can lead to millions of dollars in losses, and have a devastating effect on your business.
Learning how to stop condensation in shipping containers can help you reduce cargo damages and improve your bottom line.
What is Shipping Container Condensation?
Shipping container condensation occurs when the walls of a container become cooler than the dew point of the air found inside the container. Because shipping containers are crafted from metal, internal temperatures can shift significantly due to weather changes and other external factors. When the container cools significantly, the air is no longer able to contain its moisture—it has reached its dew point.
Once this occurs, the moisture falls out of vapor into liquid form, which then builds and collects on the walls and roof. This condensation can drip on your cargo and ruin the container’s interior, resulting in significant losses.
Shipping condensation is also known as container rain, which can damage cargo through:
- Packaging deterioration
- Mold and mildew
- Caking of powder found in goods
It’s important to learn how to stop condensation in a shipping container to avoid these effects and prevent your business from incurring significant profit losses.
What Affects the Amount of Condensation in a Shipping Container?
While temperature shifts are a contributing factor, learning how to stop condensation in a container means considering all of the aspects that affect moisture during transport.
The amount of condensation in a shipping container can vary based on temperature, air space, ventilation, moisture content of the goods you’re shipping, and container usage.
- Temperature: Temperature can vary depending on transportation route and shift from day to night. When temperatures significantly change, liquid can build up in the air.
- Air Space: The more space left open in the container, the more moisture content in the air. This makes condensation issues more likely.
- Ventilation: If a shipping container is not properly ventilated, flow of air is obstructed. In certain shipping situations (depending on route and local temperatures), lack of ventilation can cause a further buildup of moisture. Air flow can help equalize temperature inside the container with temperature of the outside air; the smaller the difference between the two, the less likely condensation is.
- Moisture content of shipped goods: The hygroscopic goods in a shipping container can play a significant role in moisture levels. Paper, cardboard, wood, organic materials, chilled foods and beverages, and other commonly shipped products can release moisture when the temperature outside of the container drops. This moisture then collects on the walls and ceiling.
- Container usage: The way your container is treated during packing processes and throughout transit can also affect the likelihood of condensation. The following facets of container usage can affect the amount of moisture in the container:
- The frequency at which doors are opened
- The frequency at which a container is loaded or unloaded
- Weather conditions
- Time of day
What Happens if You Don’t Stop Condensation in a Shipping Container
Water damage can devastate a shipment, ruining goods and affecting relationships with clients. To understand the monetary loss container sweat can incur, take a look at the example below:
Imagine you’re shipping $75,000 worth of goods in a shipping container. If 10 percent of your goods were damaged by water or moisture, you’d lose $7,500 in that shipment alone. Say 20 percent of the goods were damaged; you’d be facing a loss of $15,000. Bump that up to 50 percent—you’re going to lose $37,500 in that shipment.
While a single incidence of this type of loss can be managed, repeated losses over time can devastate a business. The proof is palpable, and cases of cargo loss aren’t isolated; according to Green Carrier, approximately 10% of all containerized goods are discarded due to moisture-related damages.
These costs can quickly add up, and significantly impact your business’s profitability.
How to Stop Condensation in a Shipping Container
While it’s impossible to completely prevent moisture buildup, there are ways to control condensation in your shipping container.
• Use the Right Pallets
Using pallets to store your goods is common practice, but it’s important to consider the moisture content found in wood varieties. The pallet industry is hard-pressed to provide pallets quickly, and this requires the use of fresh lumber—often overloaded with moisture content. If the wood is used when still wet, it can contribute moisture to the air and worsen shipping container condensation. Perhaps your pallets aren’t new, but rather made from old wood that’s been stored in cold, wet places throughout chilly winters. These pallets are likely just as laden with moisture.
Using plastic pallets may help reduce shipping container condensation, as they don’t absorb moisture in the air. If you need to use wooden pallets, be sure that these pallets are dried before loading.
• Use Desiccants
Desiccants are products that absorb excess water from the air, effectively reducing the dew point inside the container. Shipping companies often place desiccants inside a shipping container to reduce moisture that results from products, packaging, or temperature fluctuations.
Desiccants come in a variety of forms. Depending on your needs and the goods in your cargo, you might choose from the following types of desiccant:
- Desiccant Bags: Desiccant bags are used to absorb the humidity in a shipping container, and can be hung from the ceiling and along the walls to help reduce the moisture in the air. As the desiccant traps moisture, it reduces the dew point temperature, preventing condensation from forming on the walls of the container.
- Desiccant Blankets: This type of desiccant is laid or hung over the top of goods in the container. It’s designed to prevent condensation from building in the air and protects the goods below it from droplets of water. These blankets feature a breathable membrane that allows existing moisture from the goods to filter upwards through the blanket, while offering a leak proof design that prevent moisture from moving downwards—also called container rain. Some desiccant blankets are designed to create a perfectly sealed environment that prevents the flow of cold or hot air through the container, thereby reducing temperature shifts that could lead to shipping container condensation.
- Desiccant pads: Desiccant pads are essential when shipping chilled goods or beverages. These pads are laid below the goods themselves; should leakage occur, the pad soaks up the extra moisture to prevent shipping container rain and fungus growth. Many desiccant pads offer thermal protection that maintains the shipping container’s temperature to avoid the buildup of moisture.
If you’re wondering how to stop condensation in shipping containers, desiccants could be an important part of the puzzle. Desiccants can help prevent condensation buildup, but it’s important that you use the right material, and the right amount of material to properly shield your cargo.
• Consider Dehumidifiers
If you need to learn how to stop condensation in a shipping container that’s used for storage, consider a dehumidifier. If your shipping container has access to a strong power source, a dehumidifier can be used to suck the moisture from the air. Keep in mind that you’ll need to regularly empty the dehumidifier of water or set up a hose system that can plumb the collected moisture back out of the container.
• Improve Insulation
Insulating your shipping container can greatly reduce the amount of moisture in the air and prevent container rain. Container insulation can keep the contents of your cargo warmer than the dew point, which ultimately prevents extreme temperature differences that lead to condensation.
• Improve Ventilation