Frequently Asked Questions – Moisture Absorber

Installation of Moisture Absorber in containers for international shipments

1. How do desiccants help solve moisture problems?
   This unique product absorbs moisture by extracting water vapor present in the air, thus preventing the humidity inside the container from reaching dew point and condensing. The desiccant then starts to turn into a gel as it continues to absorb moisture. The water absorbed is retained due to the presence of a special binding agent, thus preventing it from leaking. Lower relative humidity InterDry controls the humidity inside containers by preventing the air from reaching dew point and condensing, thus protecting your precious cargo.
2. What is Relative Humidity (RH)?
   Relative humidity measures the amount of moisture in the air. It is expressed in a percentage of how much moisture the air could possibly hold. The wetter or damper the air is, the higher the relative humidity. The drier the air feels, the lower the relative humidity. Thus, 100% humidity is actually rain.
3. What are the most common problems caused by moisture?
   Moisture in containers causes problems such as mold, fungus, mildew, rust decay, lumping, caking, agglomeration, and decomposition. Moisture can also cause electronics to malfunction.
4. Is moisture damage always instantly visible when handling the cargo?
   Unfortunately not. Though common forms of moisture problems such as corrosion, mold, or fungus are visible on the cartons, surfaces etc. there are some kinds of damages that are not visible. Mostly these damages are internal and visible only when the customer opens the shipments. In the case of devices, they often cease to function the way they should.
5. I fumigate my containers; do I still need to put in desiccants?
   Fumigation and using desiccants have two different purposes and are not alternatives to protect your goods against moisture damage. Fumigation is primarily to eliminate insects and eggs in the container and in the goods. It has no influence on the humidity inside a container. Desiccants will not influence the effects of fumigation and can easily be put in before or after fumigation.
6. If I use desiccant, will I have any more moisture problems?
   Dessicant prevents moisture damage by controlling the Relative humidity and indeed prevents those problems. However, the ventilation holes in the container need to be closed and the number of units to be put in a container needs to be adjusted to the situation.
7. I load my container under dry conditions and it is tightly sealed. Why are there moisture problems?
   If there are still moisture problems, we can easily say that the number of units per containers currently is not sufficient and it is advisable to increase the units per container. There are many factors for bigger amounts of moisture inside the container. Examples of those factors are:
   1. Container Floor: Recent studies carried out by R&D department, proved that the moisture content of the wooden floors is higher than they used to be. That is partly because of the quality of the wood that is being used nowadays and partly because the floors are being cleaned with water and they are not dried out enough before being used.
   2. Packaging: Wooden pallets always contain more than 20 % moisture, which always causes problems whichever products are put on the pallets. The packaging, often being cartons, contains a lot of moisture in itself, which will spread into the cargo or vaporizes into the air.
   3. Products: The biggest factor of moisture inside a container is the products itself. The MC varies roughly spoken between 10% and 35%. When the MC reach the 25%, the cargo is in the danger zone.
   4. Journey and climate factors: When all the above mentioned factors are controlled and there is still a problem, they surely are the conditions during transport. The first point of consideration is the transport time. It depends on the destination and more importantly the climate during shipment and final destination. Basically, the changes in temperature and automatically the relative humidity is the cause of condensation. If long transits cannot be avoided, again our advice is to add more units to absorb the extra water molecules.
8. I ship consumer goods in tubes/cans/jars etc that contain no moisture, yet I still have problems.
   As said before the moisture comes from the container floor, pallets, open ventilations, weather change during journey. And it will condense on the tubes/cans/jars that cause corrosion and labels to fall off.
9. Each container of my cargo of peanuts/coffee/cocoa contains tons of moisture. What difference does it make if the desiccant absorbs a few liters moisture during a voyage?
   Desiccants absorb the exceeding water molecules in the air and reduces the Relative Humidity inside the container, so that it will not reach the dew point.
10. Does it make a lot of difference that my cocoa beans have a moisture content of 8% instead of 7%?
    One percent more or less doesn’t make a difference, especially not when the MC is on the lower side.
11. My cargo of peanuts had suffered damage in the centre even though the outside of the cargo looked fine and there were no signs of condensation. Why?
    Condensation on the surface of your cargos can evaporate quickly, but it takes more time for the moisture which gets trapped deeper. Before it evaporates back to the air, mold and fungus would have already grown.
12. How does Silica gel works?
    Silica gel is the most common type of desiccant in use today. It is porous sand and can absorb moisture in the air. However, silica gel absorbs moisture best in small, confined spaces and often ends up getting saturated in a very short time span, making them unsuitable for container shipments. Beware that some silica gel – the blue contains cobalt – is toxic, and cannot be disposed of any which way.
13. Do I still need to use silica gel in my boxes?
    It is definitely not a bad idea to use sachets of silica where the air is tight, and moisture is trapped, like in boxes and items packed in plastics.
14. My cargo was damaged even though I used a lot of silica gel and there was no condensation. Would it help to switch to special container desiccant?
    Perhaps there was not enough Silica Gel put inside the container. You need about 40Kg Silica Gel for a 20″ container. I can assure you a better result with specialized container desiccant. Silica works pretty well in smaller closed spaces, like shoeboxes. It absorbs very quickly and is often already saturated before the container is moved.
15. What is so great about container desiccant anyway?
    We have superb products that actually reduce the RH inside the container. When it absorbs moisture, the powder base will change into a gel. It is more efficient and safe in use. Even when the product gets damaged, it will not spill any water on the goods. It is easy, safe, and inexpensive solution for the problems with moisture damage.
16. How many units must be put in one container?
    That depends on many things. The container size, the cargo, moisture of cargo, moisture of container’s floor, moisture of pallets, length of journey, and weather during journey and so on. An example: a 20 feet container with KD (Kiln Dried) furniture needs 4-6 units, while 20″ air dried furniture needs 6-8 units. We generally offer expert advice regarding optimum usage of the desiccants for best results.
17. Do I need to line my container with Kraft paper?
    Kraft paper is a commonly used method of containing “rainfall” that occurs inside a container. Normally it is installed under the ceiling to absorb the moisture that may occur due to container rain. It is most useful while shipping goods that have very high moisture condensation, but it cannot replace a desiccant that soaks up the humidity before it even turns into rain.
18. My containers are stuffed till the top. Can container desiccant still be useful?
    It seems that there is almost no free air in the container, while there is actually a lot of free air between the products, and InterDry absorbs the moisture in that air and prevents condensation.
19. I have problems with mold growth inside my shrink-wrapped pallets. Will container desiccant help?
    No, unless you make holes so the water molecules won’t get trapped.
20. My shipment of steel/galvanized components, aluminum, machinery etc. arrives corroded, stained or discolored, despite heavy packaging. Will container desiccant help?
    Yes, as long as you put enough units per containers and do not wrap the items in plastic.
21. Can I re-use my container desiccant?
    Container desiccants are one-time usable, environmentally friendly and disposable as normal waste.
22. My cargoes are outdoor furniture with brass parts on it. When the goods arrive at the destination, the wooden part is in perfect condition but the brass part has slight stains on it. What should I do to avoid this?
    In some cases, it can happen. I can suggest adding one or two more units and wrapping it properly with only single face carton.