Over 200 million shipping containers are transported globally every year, with the vast majority moving through different climate zones, which can create condensation in the container and lead to many kinds of damage. 

Considerable temperature fluctuations can occur inside freight containers during transport and storage and since warm air can absorb more moisture than cold air, drops in temperature in closed freight containers may result in the formation of condensation, which can result in corrosion and rusting of steel cargo, mould on packaging and goods, damp packaging and detached labels. 

Condensation in containers manifests itself in three primary ways: 'container rain’; 'container sweat’; and 'cargo sweat’, with an estimated 10% of containerised traffic experiencing moisture-related issues.

Container rain is when water on the interior surfaces of the container, concentrates and falls directly onto the cargo, while container sweat usually occurs when container walls cool and cargo sweat usually occurs when air in the container heats up faster than the cargo, with condensation forming on the surface of the packaging.

The amount of condensation in a shipping container varies widely depending on many factors, including container usage, temperature, air space, ventilation, and the moisture content of the goods being shipped. 

While it’s impossible to prevent moisture buildup entirely, there are several ways to control condensation, with ventilation and load space critical, because when the difference between internal and external temperatures is small, condensation won’t form as readily and when a container is filled there is less air to hold moisture.

However, if the shipping container is transported in mostly wet and humid conditions, ventilation can pull moist air from the outside and encourage condensation. In these cases we would recommend improving the insulation of the cargo and using desiccants to absorb excess water from the air.

Desiccant bags can be hung from the ceiling and along the walls to help reduce the moisture in the air and make condensation less likely to form on the walls of the container. While desiccant blankets are hung over the goods to prevent condensation from forming and protect products from water droplets and desiccant pads lay below goods (typically liquids) to soak up leaks or extra moisture.

Countering the formation of condensation during container transport depends on a multitude of factors, including the nature of the goods, the climatic zones transited, the size of the container, the weight and moisture content of the goods, the packaging and transport duration.

To a certain extent, shipping container condensation is inevitable, but because we have years of experience keeping containerised goods safe and dry, that doesn’t mean it has to damage your cargo. 

Our sea freight team have direct experience in the management of container equipment and work closely with our shipping line partners to ensure that containers are ventilated adequately and that they are free from damage.

If you have questions or concerns on any of the issues raised here, or have specific supply chain challenges, EMAIL Andrew Smith who can advise on the effectiveness of desiccants, humidifiers, alternative packaging and insulation for different types of cargoes and geographies.

The reliability of container shipping lines’ vessel schedules dropped at the beginning of 2023, with Sea-Intelligence reporting that schedule reliability improved for the majority of 2022, but a fall of 3.8% in January meant reliability sat at just 52.6%.

The vessel schedule reliability of all top 14 carriers fell in January 2023, with Wan Hai recording the biggest decline at 15.4% and Hapag-Lloyd the smallest at 0.4%.

ZIM was the least reliable carrier in January 2023 with schedule reliability of 41% In January, while Maersk was the most reliable line, with 58.3%, followed closely by MSC at 57.7%.

CMA-CGM, Hapag-Lloyd and Hamburg Süd’s schedule reliability passed 50%, with the remaining carriers recording schedule reliability of between 40 and 50%.

Despite January’s 3.8% schedule reliability fall to 52.6%, it is still considerably higher than the previous two years and sits some way above 2022’s dreadful schedule reliability of just 30.4%.

In January 2023, all carriers except for Hamburg Süd recorded double-digit year-on-year improvements in schedule reliability, while the average delay for late vessel arrivals is currently 5.26 days, a month-to-month improvement of 0.24 days.

From a low base, global vessel reliability improved throughout last year, particularly over the last quarter with almost 57% of all ships arriving on time at the end of the year, up from 30% in January 2022.

On the main shipping routes, the greatest improvement was seen for cargo from Europe to Asia, where reliability increased from 13% at worst to 52% now. 

In contrast, congestion on the US east coast led to the least improvement being seen among the major routes: from Asia to the US east coast and from Europe to the US east coast, where on both routes more than 40% of ships still do not arrive on schedule.

Overall vessel delays have improved significantly, meaning only 5.5% of the global container vessel fleet is unavailable due to delays and if operations continue to improve at the same pace, alongside the currently suppressed demand, global operational performance could return to normal over the next months.

The freight market is changing constantly, across all transport modes, routes and regions, which is why we work closely with our offices and network partners to monitor the global situation and share the latest intelligence, as it emerges.

To learn how we can help you avoid vessel delays, to develop supply chain resilience, or to request our regular ocean market report, please EMAIL our sea freight director, Andy Smith, who can advise on the best solutions for your ocean supply chain.