The Challenge
A manufacturer ships dense, hygroscopic cargo in sealed 40ft containers from India to Northern Europe, a voyage of roughly 25 days that crosses the equator and the Bay of Bengal. Inside a closed container the relative humidity routinely climbs past 90% on tropical legs, and the daily temperature swing between a sun-baked steel roof and a cool night causes water to condense on the ceiling and walls. That condensate drips back onto the load. This is container rain, and it shows up at destination as rust bloom on metal, water staining, softened cartons, and mould, any of which can trigger a rejected shipment or an insurance claim.
Ordinary silica gel or clay sachets do not solve this. Those adsorbents saturate at roughly 25 to 40 percent of their own weight and then stop working, usually well before the container clears tropical waters. The moisture load of a full container over 25 days is simply too large for them.
The BENZ Solution
BENZ specifies BENZPACK BE DRY ULTRA, a high-purity calcium chloride container desiccant. Calcium chloride works by absorption, not adsorption: it chemically takes in water and can hold up to 300 percent of its own weight, and over 400 percent under optimal conditions, roughly ten times what silica gel manages per unit. Critically, its uptake accelerates as humidity rises toward 100 percent, exactly the profile of a tropical container, and a modified-starch gelling agent locks the absorbed water into a leak-proof gel so it can never drip back onto the cargo.
The quantity is not guessed. It is calculated with the DIN 55474 desiccant-unit method from the container volume, the cargo and packing materials, and the length of the voyage:
- Container: 40ft, roughly 67 cubic metres of internal air volume.
- Load: timber-and-carton packed, a heavy hygroscopic moisture reserve.
- Voyage: about 25 days across tropical humidity.
- Result: approximately 10 to 12 one-kilogram BE DRY ULTRA units, hung along the container walls before the doors are sealed.
Every shipment is sized individually. Use the DIN 55474 calculator or send us your container, cargo and route for an exact figure.
The Outcome
With the right chemistry sized correctly, the container interior is held below the point where condensation forms for the full voyage. The cargo arrives dry, rust-free and assembly-ready, with no water staining or mould and no moisture-related rejection. The economics are decisive: a single container-rain event can write off cargo worth more than a full year of desiccant spend, so the protection pays for itself many times over on the first avoided claim.
Up to 300%
Moisture absorbed vs its own weight (400%+ optimal)
~10-12
1kg units for a 40ft hygroscopic load, per DIN 55474
Dry
Cargo arrives rust-free and claim-free
This is a representative application, based on the container-desiccant problem BENZ solves for exporters worldwide. Absorption figures are product specifications; quantities are illustrative of a typical 40ft hygroscopic load and are calculated per shipment.