Humidity (moisture content) has an effect on packaging reliability, as the properties of both wooden pallets and boxes and cardboard cartons and retail packages are affected by humidity in different ways and too much could cause packaging damage.
Sofeast’s Quality Engineer, Helen, who has special expertise in packaging, provided the following information.
Is there an international standard of humidity range in wood or cardboard?
There is no international standard of humidity range and acceptable levels vary in different areas/countries. Usually, the most acceptable rate should be around 8%-12%, but in some countries/areas between 6%- 14% can also be accepted.
How does humidity affect cardboard cartons?
For cartons, if the moisture content is too low, the paper is too brittle, easy to break, and the folding resistance is poor. If the moisture content of the paper is too high, the cardboard is prone to curl, which will reduce its compression strength.
How does humidity affect wood?
For wood, if the moisture content is too low, it is easy to get shrinkage, cracking, paints bursting, curl, deformation. While if the moisture content is too high, it is easy to get discoloration, swelling and cracking, mildew, worms, decay, etc.
Do we need to check the humidity of individual products, too?
Sure, this may be appropriate if the products are either prone to attracting humidity or could be damaged by it.
For example, electronic products are vulnerable to humidity and it could damage them or cause them to malfunction. On the other hand, apparel and footwear may attract humidity and be damaged or soiled by mildew, for instance.
Therefore, by checking the humidity of such items before shipping it’s possible to ascertain whether the packaging you have selected is providing enough protection from humidity, and, if it’s found wanting, actions can be taken to improve protection, such as adding a plastic wrap or including sachets of silica gel desiccant.
What tools can be used to check humidity?
A handheld moisture meter (here is an example) is usually adequate for this purpose. These battery-operated devices have a digital display and when their metallic prongs are placed onto the surface being tested they will provide a readout in % of humidity. As per the above percentages, when shipping from our fulfilment center, for example, our inspectors will use such a tool on cartons and packages.
Here you can see some images of an inspector using a moisture meter on common materials including wood, cardboard, and a sports shoe!
How to find out the cost of sending small packages from China to customers around the world? 📦
We created an easy-to-use small package shipping rates calculator which provides you with costs and shipping times to a range of countries, such as the USA, Germany, the UK, etc, from China.
