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Each year, countless tons of cargo are stored and transported across the globe in shipping containers. In fact, cargo ships carry more than 80% of the global volume of trade each year.[1] As of 2019, the international liner shipping industry transported 11 billion tons of goods worth approximately $14 trillion in millions of containers.[2]
Safely transporting cargo is a top priority in container shipping. Unfortunately, shipping container condensation presents an immense challenge for anyone transporting goods with shipping containers. The resulting moisture damage can lead to rust, corrosion, mold, mildew, and thousands or even millions in losses.
Read this guide to learn more about shipping container condensation, what you can do to stop condensation in shipping containers, and how to protect your cargo and your bottom line.
How Much Damage Can Condensation Cause?
The financial toll of shipping container condensation is staggering. According to Wagner Meters, around 10% of all container shipments are rendered unusable due to moisture-related damage, a loss rate five times higher than the average retail inventory shrinkage. And because most cargo insurance policies exclude condensation-related claims, shippers are typically left to absorb those costs entirely.
That financial hit compounds quickly when you consider the cascade of problems moisture triggers:
- Mold and mildew growth: Within 24-48 hours of moisture exposure, mold and mildew begin to grow. They can spread rapidly, often rendering entire shipments unsaleable.
- Metal corrosion: Prolonged exposure to moisture creates a chemical reaction that causes metal to corrode. Corrosion in products may not become apparent until they reach customers, leading to warranty claims and reputation damage.
- Packaging deterioration: Moisture weakens boxes and pallets, creating instability and causing crushing. Weak boxes also increase the likelihood of damage during handling.
- Electronics failure: Shipping container condensation can corrode circuit boards, rendering electronic products unusable.
- Powdered products caking: When exposed to moisture, powdered products like table salt, beverage powders, and granulated sugars cake.
- Container degradation: As shipping containers are exposed to repeated condensation, their structural integrity eventually becomes compromised.
What Is Container Rain?
Container rain is a severe form of shipping container condensation. It occurs when moisture collects on the ceiling of the container, forms droplets, and then drips down onto the cargo like rain.
This is especially damaging because it drips water directly onto products, often soaking the top layers first. Items such as electronics, textiles, paper goods, and packaged foods are particularly at risk.
Container rain is most common when warm, humid air rises and meets the container’s cold metal ceiling. It happens during overnight cooling and when containers travel from warm to colder climates.
Tracking Shipping Container Condensation Levels
The first step to eliminating shipping container condensation is to track moisture levels inside your shipping container. You can use a remote sensor in your shipping container to monitor moisture levels in real time from anywhere.
Smart sensors allow you to track temperatures and moisture levels as your cargo moves toward its destination, so you know as soon as you’ve got a problem.
If you’ve used a sensor and identified moisture problems inside your shipping containers, it’s not too late to take action to protect future shipments.
6 Ways to Stop Condensation in Shipping Containers
If you’ve used a sensor and identified moisture problems inside your shipping containers, it’s not too late to take action to protect future shipments. While there’s no way to entirely eliminate moisture inside shipping containers, especially with fluctuating temperatures during global shipping, you can control it to mitigate damage.
Use these six tips to prevent condensation in your shipping container, keep your cargo dry, and avoid sensitive cargo damage.
1. Choose the right pallets
The pallets you’re using might be contributing to condensation in your shipping container. Wood can release moisture into an otherwise dry container. Pallets that are made from fresh lumber need time to dry before being used. Even if your pallets aren’t made from new lumber, they can absorb moisture from the air wherever they’re stored, then later release it into your shipping container.
Using plastic pallets instead of wood is an easy way to minimize moisture. These are typically made from materials like polyethylene and polypropylene. They neither hold moisture or are affected by it. Unlike wooden pallets, plastic pallets can also be cleaned and sanitized to reduce mold growth in the event of excess moisture.
2. Use desiccants
Desiccants use adsorption to remove excess moisture from the air. This is the process of attracting water molecules to their surface, without actually absorbing those molecules. Desiccants are an easy way to stop condensation in a shipping container and reduce the risk of container rain. Desiccants are available in several forms, including:
- Desiccant bags – Desiccant bags hang from the interior walls of your cargo container to trap condensation in the shipping container, helping to lower the dew point and reduce the risk of container rain.
- Desiccant blankets – Desiccant blankets can be draped over the top of cargo to protect against shipping container condensation and container rain. A leak-proof design keeps moisture from traveling downward and damaging cargo. Some are even designed to be suspended from the ceiling, allowing them to absorb any container rain as it falls.
- Desiccant pads – You can use desiccant pads to line the underside of chilled goods and beverages. If there’s a spill or leak, the desiccant pads will absorb the moisture and minimize damage.
3. Consider dehumidifiers
Dehumidifiers can be a smart solution to stop condensation in shipping containers that are in storage. In order to use a dehumidifier, you’ll need a nearby power source, so this isn’t a great solution for cargo in transit. If you have access to power, try running a dehumidifier inside the container to reduce ambient moisture and prevent condensation.
Keep in mind that dehumidifiers fill with the moisture that they remove from their environment, so you’ll need to check and empty your dehumidifier regularly if you don’t have a hose set up for drainage.
4. Use insulation
Condensation in shipping containers is often caused by extreme fluctuations in temperature during transit. Warmer air is capable of holding more moisture than cold air. As temperature rapidly drops from warm to cool, the air is no longer able to retain the same amount of moisture, causing condensation to occur.
One way of preventing this phenomenon is with insulation. By insulating shipping containers, you can prevent the extreme temperature fluctuations that can lead to condensation.
Temcore container liners are an excellent choice for insulation. They feature a five-layer design that offers total protection against extreme temperature fluctuations. Our container liners are also easy to install. All you have to do is attach the click-on-top hanging system to the D-rings inside your shipping container.
Since Temcore liners create a strong seal around the interior of your shipping container, they can also prevent spoiling and cargo damage caused by contamination. As long as the contents of your container are warmer than the dew point, condensation shouldn’t be an issue.
5. Ventilate your shipping container
Is your shipping container ventilated properly? Proper ventilation helps equalize interior and exterior temperatures to reduce the likelihood of condensation in the shipping container.
Most standard shipping containers come with ventilation, but they’re typically just big enough to equalize the pressure in the shipping container, not to properly ventilate it for temperature equalization. You may want to consider adding ventilation like:
- Passive vents: These vents simply allow air to flow in and out. Install them across from each other for cross-flow
- Active vents: You can also install active ventilation like exhaust fans or roof fans. These pull hot air from inside the container and draw cool air in.
Keep in mind that, if you’re shipping or storing goods in a moist climate, ventilation may cause more condensation in your shipping container than it prevents. If the air is filled with moisture, ventilation will bring that moisture in.
6. Look for container damage
As tough and durable as they may seem, shipping containers can get damaged. Check your shipping container to see if there are any cracks or holes that might let moisture in. Significant damage may mean it’s time for a new shipping container. Here are some signs it might be time to replace your shipping container:
- Severe rust, especially rust that leads to the holes in the container
- A buckled or warped shipping container floor
- Broken doors that don’t close all the way
- Significant dents or cracks
- Doors that are difficult to open or close
Frequently Asked Questions
How Do You Eliminate Condensation in a Shipping Container?
No single method works alone to eliminate condensation in shipping containers. Instead, combine solutions based on the cargo type and its route.
- Use container desiccants to absorb moisture in the air.
- Insulate walls to minimize temperature swings.
- Use plastic pallets instead of wood
- For storage containers with power access, run a dehumidifier.
Does a Bowl of Salt Stop Condensation?
A bowl of salt is not sufficient to prevent condensation in a shipping container. While salt absorbs moisture, it eventually dissolves , potentially causing leaks and corrosion. It’s slower and less reliable than commercial container desiccants.
What Can You Put on Metal to Stop Condensation?
Anti-condensation paints absorb moisture and release it slowly, preventing dripping. Thermal barrier coatings with ceramic components reduce temperature differences. Rust-preventive primers protect against corrosion from existing moisture.
Stop Shipping Container Condensation with Eurolog Packing Group
Protecting your cargo is crucial, and stopping condensation in your shipping container is a major part of that. Using desiccants, non-absorbent pallets, and insulation can help you save millions in potential losses.
Eurolog Packing Group makes it easy to find the ideal shipping solutions for your needs. With several preexisting and custom solutions, we can help you put a stop to condensation so you can rest easy knowing your cargo will safely reach its destination.
Check out our selection of shipping container solutions online and contact us if you have any questions.
