Safety and security of goods are of utmost importance during ocean freight transportation. Damaged goods are of no use to the shipper or the consignee. Although 90% of world trade happens via robust intermodal shipping containers, one need not worry about the safety of their goods. But a few times, these containers themselves can pose a severe threat to the safety of the cargo. Container rain is among the most significant factors responsible for damaged goods. Around 10% of goods are discarded yearly due to moisture-related damages.
In this blog, we will explore container rain. What causes the container to rain? And most importantly, the ways to prevent container rain.
A buildup of moisture inside the shipping container that can potentially damage your goods can be described as container rain. Two major factors responsible for container rain are temperature variations during shipment and excess moisture. If your shipping container is not moisture-protected, then container rain will occur when the vessel passes through different climatic zones. A container loaded in a tropical environment, where the air is warm and humid, and then moved to an environment where temperatures are far cooler will most likely suffer from cargo damage caused by moisture.
What exactly happens?
Shipping containers are manufactured using metals; as a result, the temperature inside them fluctuates when they move, as the container experiences changes in weather conditions along its journey. Humidity is the water in the air which can enter the container at the loading point. During freight transport, the temperature fluctuates from day to night and through different latitudes. When the container walls become cooler, the phenomenon of condensation happens. The water vapours inside the cargo container condense into liquid, which collects on the walls and ceiling of the container. This condensation then rains down onto the cargo and damages and declines the product quality.
The concept of relative humidity (RH) plays a vital role in container rain. It is the percentage of moisture that the air can retain at a given temperature and pressure without condensation. When the temperature goes down, RH increases, and if the air is cooled enough, moisture condenses and transforms into water vapours, leading to the phenomenon of container rain. Unless this RH% is reduced, the container rain could repeatedly happen every 24 hours.
Damages due to container Rain
Container rain leads to huge losses. Every year, millions of dollars of cargo get discarded because of moisture damage incurred during shipments. When the container raindrops on the goods, it damages the packaging and labels. Due to this, moisture-sensitive interests begin to grow mould, further deteriorating product quality. As mentioned at the beginning, container rain is accountable for destroying approximately 10% of the cargo. This issue has caused massive trouble within the maritime industry for a long time. Proper steps must be followed for safe and secure cargo shipment across the ocean and to help reduce container rain.
Ways to prevent container rain
To prevent your goods from the harmful effects of container rain, one must check the container thoroughly before loading goods and keep in mind the below-mentioned points
- Is the container airtight?
For maximum protection of your goods, it is essential to check that the cargo container is in good condition and has no holes or damaged doors. Make sure to check the ventilation holes. It is impossible to get an airtight container. Still, a cargo unit in its good state will aid in reducing the amount of moisture moving into the container under ordinary circumstances. In the case of shipping dry cargo, you can also tape the ventilation holes.
- Is the container dry?
Before loading your precious cargo into the container, make sure that the container is entirely dry. Please pay special attention to the wooden flooring, as it can hold up to 100 litres of water and bring extra moisture into the container. A handheld moisture meter can help you quickly check the moisture content of the container flooring.
Mentioned below are some other ways that help to mitigate the container rain
- Efficient ventilation system
Installation of high-quality vents helps to maintain the air inside the container at the same temperature as the air outside the container. A proper ventilation system helps draw out the moist air and allows the ambient temperature air to circulate inside the container, thus equalizing the temperature inside and outside the container. A highly efficient ventilation system will help to reduce the moisture and condensation within the container, thus keeping it moisture-free.
- Right pallet choice
Choosing the correct type of pallet can make all of the difference, as they are the fundamental structure of a shipping container that permits handling and storage efficiencies. It is a well-known fact that wood is quite effective in absorbing moisture. Therefore one must try and avoid the usage of wooden pallets in the container when not necessary. If you use pallets, ensure they are entirely dried before loading goods. High-quality plastic pallets can be an excellent alternative for the shipment of moisture-sensitive goods. Be extra careful while loading cargo near the ocean as the moist weather will uncover the wooden pallets to the ocean air, which leads to extreme mould buildup in the shipping container during shipment.
- Moisture check
Before loading your cargo into the vessel, ensure that the temperature inside the container is appropriate and will not lead to excess moisture accumulation. Wipe off the moisture, if there is any, in the container. This simple yet effective step can help save your shipment from the potential risk of moisture damage.
If the wall of the shipping container is insulated, then the temperature fluctuations will not have extreme effects on the goods placed inside the container. An insulated container wall will help to prevent excessive temperature differences and thus will significantly reduce the buildup of moisture, keeping the risk of container rain at bay. Insulation further helps with thermal performance and limited air circulation in the container.
Use the best quality desiccants while shipping fragile or moisture-sensitive goods at greater risk of container rain and fungus. The desiccant is a hygroscopic substance which is a drying agent for substantially reducing relative humidity. It absorbs the excess moisture and humidity in the environment and keeps the goods safe and dry throughout the journey. Today a wide variety of desiccants are available in different shapes and sizes, which effectively help to prevent container rain.
- Dehumidifiers and air conditioning
Although this method is among the most expensive and complex ways to prevent container rain, air conditioners and dehumidifiers work wonders in keeping stable dry conditions for the most moisture-sensitive container contents. A significant problem with such a method is that it requires a regular source of electricity, without which they are at risk of failing.
Container rain is a threat which can generate many severe problems like corrosion and promote moulds and fungi growth. Discarding ten per cent of your cargo is very costly in the long run. If we assimilate the value of jettisoned cargo for the next ten years, the amount of money on losses is relatively high, and the economy will suffer a significant loss; therefore, it is crucial to address the moisture issue of cargo containers. One must check the container before loading cargo to keep the condensation away from the start. Suitable pallets, dehumidifiers, air conditioning, and desiccants are additional ways to protect sensitive freight and dry items.