When relative humidity is at least 90%, use these desiccants. They are often used to protect cargo sent in large containers from moisture.
The area covered is calculated at 77° F and 90% relative humidity.
Bags
Bag
Bag With Hanging Strap
and Locking Carabiner
10 1/4" Long—Thirty-two 10 1/4" long desiccant bags are recommended for a 20-ft. shipping container.
22" Long—22" long desiccant bags are best for large sea containers, rail cars, and river barges. They have a hanging strap and a locking carabiner, so you can secure them off the floor to save valuable floor space. Three bags are recommended for a 20-ft. shipping container.