Sweat in Shipping Containers

This guide is intended to discuss the causes the treatment methods for sweat or condensation in shipping containers. If you are shipping goods or using a shipping container for storage use and you worry about container sweat please read on!

Do Shipping Containers get Damp?

Yes – shipping containers will get damp. As they cool down overnight, water suspended within the air inside your container will condense against any cool surface which will cause a layer of damp or condensation to form on the inside of the roof. This can drip down into the cargo space of the container and potentially damage goods inside your shipping container.

Do Shipping Containers Sweat?

Grafotherm
Grafotherm

Yes Рthis is the same process as described above with a different name. As a shipping container cools down overnight, water suspended within the air inside your container will condense against any cool surface which will cause a layer of sweat or condensation to form on the inside of the roof. This can happen in almost any climate globally.

What is Container Rain?

Container rain is the process of condensed water that has formed on the inside of the container roof, falling down and ‘raining’ on your goods inside the shipping container. This can damage cargo being shipped or any goods being stored inside the shipping container. We outline various ways to tackle this below.

How much damp will i get in a 20ft or 40ft shipping container?

The amount of volume of damp that you get in a shipping container will vary depending on a number of factors

  • How full is your shipping container? the more cargo you have inside your container, the less free air remains. As condensation forms from this free air, the less air you have the less condensation you will get
  • The rate at which the container cools down (The weather conditions or the general climate in your part of the world). The faster the outside of the shipping container cools, the more condensation will form (assuming the shipping container is untreated)
  • How old (how damaged / how worn) is your shipping container? Anecdotally we can report that younger shipping containers experience less damp. This we believe is down to a less or not at all damaged or worn container roof may have slightly better thermal insulating properties when compared to a used shipping container roof.
  • Other external factors. did you carry any more damp into the shipping container. If you loaded it when it was raining there is a good chance you carried more water into the container which will now evaporate into the air and then condense?

Unfortunately the amount of damp experienced in a shipping container can vary widely so we don’t’ think it would be fair to quote a firm figure here. Across the whole roof of a 40ft container a number of litres of damp would not be out of expectations but this will rarely all fall into the cargo space.

Will every shipping container get damp?

All normal / standard (or dry) shipping containers will suffer from damp or condensation if untreated. The condensation forms as the shipping container cools, so only refrigerated shipping containers (which have a lot of insulation built in) and standard containers whcih have otherwise been insulated after manufacturer will be free of damp or condensation.

Fortunately there are a wide range of options available to prevent or treat damp in shipping containers. Please feel free to check out our ultimate guide to shipping container condensation treatments for a wide range of temporary, permanent, DIY and ‘supplied by us’ solutions.

Will Damp or condensation in my shipping container damage the goods?

This very much depends on what your goods (or cargo) is as well as how is it packed or wrapped. Unless very specific factors are at play all your condensation will form on, and drip off the roof only. Condensation will typically not form on the sides of a shipping container unless it is exposed to extreme cold on one side only for some reason.

Some customers get away with making sure their goods are well wrapped and perhaps covered with an extra layer of plastic sheeting which will act as a waterproof barrier between any moisture and the goods.

But if your goods are very sensitive to moisture, for example foodstuffs that may spoil, expensive artworks, fabrics and textiles all may spoil if exposed to water and especially when the goods are high value some form of condensation treatment for your shipping container may be wise.

grafo manExporters commonly go for our range of desiccants which are proven effective in the worldwide shipping market.

How do I remove damp from a shipping container?

There are 3 common ways to deal with damp or sweat in a shipping container:

  • Thermal Barrier. Line and insulate your container to slow the rate at which the air inside your container cools down, preventing the condensation from forming in the first instance.
  • Desiccants. (AKA: Damp sticks, moisture absorbers, silica gel. These can easily hung inside the shipping container and these will soak up any moisture directly from the air.
  • Dehumidifiers or heaters. Both require power and this is not suitable for exporters but reasonably commonplace for private storage containers.

for more detailed info on the products available and how they are used, please feel free to check out our ultimate guide to shipping container condensation treatments.

Still having issues with or questions about damp in shipping containers?

With years of experience supplying shipping containers for exporters as well as selling shipping containers for storage use and supplying converted containers for a wide range of specialised applications – whilst we will never say we’ve seen it all we’ve come across the vast majority of common applications and questions about shipping containers.

If your looking for a shipping container, please feel free to browse our online catalogue where you will find the biggest online range of shipping containers that we know of.

If your still stuck with any condensation issues please feel free to contact us with any questions.

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