MIL-D-3464E Desiccant usually are clay or silica gel based desiccant which will be used in electronic industry. Available sizes in 1/6, 1/3,...32 units
20% RH, the activated clay bags will absorb 50% more moisture than required by MIL-P-116-E,
whereas silica gel will only absorb 3.5% more moisture than required by MIL-D-3464E. It also
meets Method II Packaging Standards in MIL-P-116-E, which covers the basic requirements of
military packaging methods of preservation. This involves packaging an item inside a sealed
waterproof and moisture vapour-proof container with the inclusion of a desiccant to prevent
rust, mildew or corrosion damage. In Method II packaging, the package is maintained at a safe
humidity below 40% RH during the normal storage period of 18 months to 2 years.
What factors affect the amount of desiccant needed in an enclosure?
There is not an easy way to calculate how much desiccant is needed in an enclosure or how quickly the desiccant will need to be replaced. The following conditions affect the replacement interval:
How much humidity the enclosure is exposed to
The size of the enclosure
How often the enclosure door is opened and how long the door remains open
How airtight the enclosure is
It may be advantageous to use more than one desiccant packet at a time inside an enclosure. Campbell Scientific recommends keeping an extra supply of desiccant on hand for as-needed replacement in the enclosure.
When should the desiccant inside an enclosure be replaced?
The desiccant should be replaced when the top colored dot on the humidity indicator card (pn 28878) turns pink; the humidity indicator card is included in the enclosure supply kit that is shipped with each enclosure. If the CS210, Enclosure Humidity Sensor, is used, replace the desiccant when the measured humidity exceeds 35%.