IP5X and IP6X Dust Test: Talcum, Concentration and Duration

Dust testing looks crude and is actually tightly specified. The powder, its concentration, the circulation method and the duration all affect whether a product passes, and labs that improvise produce results that cannot be compared.

The powder

The standard specifies talcum powder with a defined particle size distribution, typically passing a 75 micrometre sieve. Cement, flour or sand are not substitutes: particle shape and size determine whether dust penetrates a given gap.

Concentration and circulation

The chamber holds 2 kg of powder per cubic metre of volume, with a maximum total of 2 kg, and the powder is kept suspended by a blower for the duration of the test. A chamber that settles its dust in the first ten minutes is not testing for eight hours.

Duration and pressure

The test runs for 8 hours. For IP5X the enclosure may breathe normally; for IP6X the standard allows a partial vacuum inside the enclosure, up to 2 kPa below atmospheric, to simulate thermal cycling that draws dust in. If a vacuum is used, it must be applied continuously and monitored.

Pass criteria

IP5X allows some ingress provided it does not interfere with operation or safety; IP6X allows none. Inspect the interior under good light, and check moving parts and contacts specifically, since a small amount of dust in a bearing is more serious than a visible film on a housing wall.

Related technical notes

• Turntable Speed in IP Testing: Why 1 rpm Matters
• IPX4 or IPX5: Choosing the Right Water Level
• Preconditioning Before an IP Test: The Step Everyone Skips