Stopping container rain with calcium chloride systems sized to the box and the voyage.
The problem
A sealed container is a closed system with a large thermal mass and a steel ceiling. Every night the roof cools below the dew point of the air inside, water condenses there, and in the morning it drips back down onto the cargo. Shippers call it container rain; underwriters call it a claim.
Silica gel cannot fix this — it saturates at 40% of its weight and a container holds far more water than that. Calcium chloride systems absorb over 200% of their weight and retain it as a gel or brine that cannot run back into the load.
The method
A repeatable sequence, in the order that matters. Skipping the first step is the usual reason the rest disappoints.
Ambient air, cargo moisture content, packaging materials and any dunnage all contribute.
Absorpoles hang in the corrugated side-panel recess. Container bags hang from the rails. Adhesive cargo bags mount flat where there is no hanging point.
Four to eight poles per 20 ft container is the working range, moving toward eight for long humid routes and hygroscopic cargo.
Desiccant belongs in the air space near the ceiling where condensation forms, not buried in the load.
Record placement and dosage so a claim, if it happens, has evidence behind it.
What you will need
Calcium chloride hanging pole
Vertical calcium chloride poles that hang in the corrugated recess of a container side panel and collect brine in a sealed chamber.
Four to eight poles protect a full 20 ft container
Dual-layer container desiccant
Leak-proof dual-layer Tyvek and non-woven bags that hold a sea container dry across a full long-haul voyage.
Over 200% absorption capacity, protecting for more than 90 days
Calcium chloride & bentonite clay
High-profile food-grade desiccant in DuPont Tyvek, blending bentonite clay with calcium chloride.
Stops container rain, dewdrops and transit odour
Adhesive-mounted cargo bags
1 kg units supplied as 200 g × 5 strips with an adhesive sticker for direct mounting.
Sticks in place — no hooks, no hanging points needed
Calcium chloride hanging unit
Our own calcium chloride moisture absorber in a hanging format, available from just 25 pieces.
Low minimum order for trial shipments
Food-grade calcium chloride packs
Food-grade calcium chloride desiccant packs for high-moisture cargo.
High-capacity absorption in a food-grade pack
Who this applies to
Talk to our experts
Send us the product, the enclosure, the route and the storage period. You will get a desiccant type, a dose and a format back — not just a price list.