Container breathing? It’s time to go back to school
Physics at school… you either loved it, hated it or were lost somewhere in the middle. That all changes today. Now we’re all going to love physics and how it helps us deal with the life of our goods out on the open seas.
How much do you remember from your school physics? The angle of incidence equals the angle of reflection? Ohm’s Law might ring a bell … Volts = Amps x Resistance? And there’s a good chance you’ll remember Charles’s Law – the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature, if the pressure remains constant. Or V = kT if that floats your boat.
Respect the law
Right about now, you’re either journeying into the past remembering the time you almost electrocuted your friend in the lab. Or you’re wondering why on earth we’re talking about laws on gases and temperature. Well, the reason we’re giving you a refresher course is so you’ll understand how Charles’s Law can affect container moisture and needs to be incorporated into an effective moisture damage prevention solution. Yeah, it just got real …
During a voyage half-way around the world, the temperature in the container will rise every day and fall every night. This temperature fluctuation means that the air expands during the day, spilling out from the container and then contracts, bringing in new, humid sea air at night. This is what is called container breathing.
Time is not on your side
So, why should you care? Well, the difference in temperature between sunlight on a container and darkness can be 30°C or more. That can translate into a 10% change in volume and 10% new air being brought in every 24 hours. Which in turn can add an extra 1 decilitre of moisture every day for a standard container. You might think that a decilitre isn’t so much. But repeat that every day for 3-5 weeks of a voyage plus waiting in port and we’re talking 2-3.5 litres of water … on top of what you would already calculate for a container.
So you have to take container breathing into account – especially with the risk of delays in transit and port congestion. How will this extra moisture affect your goods? How will it affect your choice of packaging? And how much moisture do those wooden pallets already sweat out during the day?
Clearly, you never want to be in the danger zone when it comes to precious cargo. The good news is that you never have to. Just get a moisture protection solution tailored around your goods and their journey – plus cost-effective dimensioning thanks to the most powerful calcium chloride-based desiccants. Then you and your container can breathe easy.
End of lesson. And this time no homework.
Talk to us
You haven’t got time to worry about optimal moisture damage prevention, but that’s pretty much all we think about. So just gives us a call – we’re here to help.