Temperature & Humidity in Ocean Containers

Effect of Container Contents:
In our recordings, a typical shipment will see an increase in humidity as the temperature
drops within a container. However, at some point, humidity stabilizes and eventually falls even as
the temperature continues to drop. We believe the corrugated boxes in the container slowly
absorbed the moisture from the air preventing condensation at the lower ocean temperatures.
To test this theory, we recreated these ocean conditions using an environmental chamber
and large sealed jars to simulate an ocean container. One jar held fiberboard boxes, while the
other held plastic boxes of the same volume. The jars were exposed to 86° F [30°C], 75%
humidity for 48 hours before being sealed. As Figure 12 shows, the simulated container with the
fiberboard boxes had a much lower relative humidity. Clearly the contents can change the
relative humidity.
Temperature F and Relative
Humidity %
100
90
80
70
60
50
40
Figure 12: Simulated Container Test
Temperature
Humidity-Jar with Plastic Boxes
Humidity- Jar with Fiberboard Boxes
0:00:00 48:00:00 96:00:00 144:00:00 192:00:00 240:00:00
Time
Conclusion:
We now have a much greater understanding of the temperature and humidity conditions
in an ocean container for some of our common shipping routes. While we learned much about
our distribution environment, we also raised a number of questions. Further study focused on
quantifying the affect of certain variables may be useful. Some areas that could be further
explored include: container color and design, position on the ship, type of load, positions along
the length, width and height of the container, position at port, routing differences.
References
(1) Onset computer website:
http://www.onsetcomp.com/Products/Product_Pages/hobo_u12_loggers/u12_logger_specs.html
Ocean Container Temperature and Humidity Study
Dave Leinberger – Dimensions.06
34
29
24
19
14
9
4
Temperature C