Shipping Container Moisture Problems
Condensation can appear when storing in shipping containers and during the inclement months of the year this can
become more of an issue. There are a number of contributory factors that create this problem. To understand this
problem in greater detail well endeavour to explain. Used shipping containers may have moisture in the floors from
previous uses, and even new builds if left shut for prolonged periods may produce some moisture inside.
The biggest fact anyone needs to know is and ultimately digest is the fact that
ISO SHIPPING CONTAINERS DO NOT CONDENSATE WHAT IS PLACED IN THEM CAUSES THE PROBLEM
Much is written and much is debated about this subject please read this section of our website to understand what
causes and what solutions there are to avoid this issue. After many years in the industry we have become a
seasoned veteran in this subject. It is the subject most self storage people discuss and do not understand see web
Fabrication and Site Services UK have extensive shipping container background with over 30 years in the industry.
Our new build containers have vented doors and front panels, increased airflow reduces the opportunity to create
moisture from damp or wet cargo. See our website www.multiboxxuk.com for a photographic library of these units.
The items you are storing may well contain moisture of some kind even a bed mattress has a moisture content.
Other house hold items like dishwashers, clothing washing machines, fridges and freezers, even in winter or summer,
will turn that moisture to vapour and as the temperature changes. Ultimately the result is that vapour will become
water droplets that gather on the ceiling and start falling to the floor or on stored items. To help prevent this there are
many views and suggestions about, but in reality the most successful method is the use of chemical dehumidifiers.
These work very well as they either contain silica gel or desiccant clay depending on the product you buy. Shipping
lines have always traditionally used gel packets within clothing containers and electrical goods transportation.
However “dry poles” as they have become known do work well. The costs vary greatly but you should not pay any
more than around £30.00 each. Our recommended supplier of these is us!! a very good and environmentally safe
product supplier. Ours is the only EEC safety approved product on the market, with official EEC regulations set out
on the instruction panel of each unit.
Manually insulating shipping containers with ply clad compressed foam works but it is costly to achieve. Take a look
at www.welderjohn13.com our online shop for photos of insulated containers we build they are exceptionally good and
have enormous insulated properties.
Equally there is another product proven to be helpful in this area this is like a spray on porridge type product which is
water based. This seems a very strange way to eliminate moisture but it is very good in the short term. This insulates
the roof internally keeping heat in and cold out. Please contact us if you wish to learn more about this method of
Container moisture technical bulletin
When deciding whether a certain Shipping Container is suitable for transporting a certain cargo, it is vital for those
involved to have sufficient knowledge about the anticipated climatic conditions in the Shipping Container. The three
major factors which have a decisive impact upon the crypto climate (microclimate) in the Shipping Container are as
follows : external climatic conditions, the type of Shipping Container and the cargo being transported.
External climatic conditions have a decisive impact upon the climatic conditions inside containers. The transport
route in particular determines external climatic conditions, season and time of day and the current weather (rain,
sunlight etc.). Due to the diversity of these factors, it is not straightforward to predict how the container climate will
change in transit. It is not possible simply to transfer the experience gained from one transport operation to another,
as the conditions prevailing in transit often vary greatly, but an awareness of how the factors interact is helpful in
assessing transport risks. In a nutshell mother nature rules the roost.
The factors influencing Shipping Container climate are highlighted in greater detail below:
1. Temperature conditions in the container:
The temperatures encountered in containers are primarily determined by heat exchange across the container walls.
Good heat-transfer properties, especially through the steel walls, and the relatively large ratio of container surface
area to container volume have a favourable impact in this respect. There are reflective materials available on the
market to reduce heat transfer, although expensive.
In addition to solar radiation, external air temperatures, wind and precipitation also have an impact upon
temperatures. Due to the wide variation in levels of solar radiation over a day, considerable temperature variation also
occurs inside the container. This particularly applies to the air layers located directly beneath the container roof, as
this is where the effects of solar radiation are at their strongest and thus where the greatest heat exchange occurs.
On exposure to precipitation, such as rain, the container roof likewise cools more rapidly than, for example, the
sidewalls, and the underside of the roof thus cools down most readily. Overheating of the air inside the container, i.e.
heating to above the external air temperature may be considerable even under normal weather conditions. In contrast,
the variations in temperature of the cargo inside the container are less marked.
2. Humidity conditions in the container:
Humidity conditions in the container are primarily determined by internal factors, i.e. the prevailing conditions are
largely determined by the hygroscopic characteristics of the cargo and its packaging. Hygroscopic auxiliary
packaging materials, such as squared lumber for cargo securing, and the water content of the flooring may also play
a significant part. Incoming outside air usually has no negative impact upon humidity. Since the temperature
prevailing inside the container is generally higher than the outside temperature, incoming air would also reduce
relative humidity. Seawater or rain may penetrate damaged containers. This constitutes a considerable potential risk.
If the container is packed in wet weather (snow, rain), additional moisture may get into the container.
As always the visual inspection of Shipping Containers is crucial for the safe transit of goods. Refer to our web site on
Shipping Container inspection for useful pro-active information. Any of our team will be able to offer services relating to
repairs and inspection along with CSC certification.
any queries you may have. If you need help contact us on + 44 2380 361247 or use email