Mil-D 3464E is a U.S. military specification for clay and silica gel bags. One “Unit” is the amount needed to adsorb 3 grams of water at 25˚C and 20% RH, and also 6 grams at 40% RH. The approximate weight of a unit is one ounce, when dry.

Classifications

Type I – the basic requirements for absorption, reactivation, dusting, and durability.

Type II – same requirements as Type I, but with a fabric that’s low dust (usually Tyvek).

Type III – same requirements of Type I, but with a fabric that’s resistance to hot water.

Specification for dust is less than 5.0 mg/unit for Type I and III, and less than 0.5 mg/unit for Type II.

Reactivation

Mil Spec. bags can be reactivated in an oven. On each bags is printed the temperature and time needed. After reactivation, the bags must have 90% of their original adsorption capacity and be able to pass a drop test, to show that the sealing is still intact.

Markings

This information shall be printed on each bag:

  • Desiccant, Activated, Bagged For Package Use and Static Dehumidification
  • MIL-D-3464
  • Type I, II, or III
  • Manufacturer’s designation
  • Number of Unit’s
  • Reactivation temperature in bag ____ºF
  • Reactivation time ____ hours
  • Manufacturer’s name and address