Q & A: What is the correct order for Sand, Dust, and Salt Fog in MIL-STD-810

Blowing Sand and Dust Chamber for MIL-STD-810, MIL-STD-202 and RTCA DO-160

Question: I have a military customer who requiresBlowing Sand, Blowing Dust, and Salt Fog tests according to MIL-STD-810. However, my customer did not specify which test should be performed first. Is there a specific order in which these tests should be performed? Does it matter?NTS Answer: Although not necessarily clear in previous revisions, guidance was added to Method 509 starting with the F revision of MIL-STD-810:

Although generally inappropriate, if sand and dust testing is required on the same test item, perform it following salt fog testing.

This is due to the fact that the sand and dust tests can produce severe abrasion of a test item. This is particularly true for the surface treatments often applied to the exterior surfaces of items in order to reduce or eliminate the possibility of corrosion. Paint, anodizing, iridite, and other surface preparations can all be adversely compromised by the sand and dust tests so that the test item could easily show corrosive effects if subsequently subjected to the salt fog test.Additional guidance was also added to method 510 (Sand & Dust):

If both sand and dust procedures are to be applied to the same test item, it is generally more appropriate to conduct the less damaging first, i.e., blowing dust and then blowing sand.

Therefore, the most appropriate sequence for the three tests in question would be:1. Salt Fog2. Blowing Dust 3. Blowing Sand