Experience has shown that dust accumulations of 13 mm (0.5 inch) on the test item are not uncommon during the chamber dust exposure. This can create a condition that may not be experienced in the life cycle of the test item. This layer of dust may form a protective layer over the seals. Removing the dust during the reorientation of the test item may provide a more realistic application of the fielded environment. If dust removal is to be performed, the item specific dust removal procedures shall be documented prior to test in the approved test plan.
In the event of an operational test this build-up of dust will reduce the ability of the test item to shed the thermal load generated by electronics. If dust accumulations are expected in the field perform the operational test without removing the dust. If the item will be routinely maintained or exposed to other environments (high winds, rain, etc.) that will mitigate dust buildup consider removing the dust prior to operation.
Procedures for dust removal must reflect the in service use in accordance with the field manual with the tools available in the field. Remove accumulated dust from the test item by brushing or wiping taking care to avoid introduction of additional dust or disturbing any that may have already entered the test item. Do not remove dust by either air blast or vacuum cleaning unless these methods are likely to be used in service.
Photographs prior to and following the dust removal must be performed.