IPX8: Continuous Immersion by Agreement

Unlike IPX7, IPX8 does not prescribe a depth or a duration. It requires continuous immersion under conditions agreed between manufacturer and user, and the agreement has to be more severe than the IPX7 conditions.

What must be declared

A valid IPX8 claim states the depth and the duration, for example 5 metres for 60 minutes, and the standard requires that these be more severe than 1 metre for 30 minutes. A product marked simply IPX8 without a stated depth is telling you nothing useful.

Pressure and sealing

At 10 metres the hydrostatic pressure is about 1 bar above atmosphere, which is enough to compress a soft gasket and to force water past a cable entry that relies on a light interference fit. Seals that rely on a lip and a spring work better under pressure; flat gaskets with low compression set do not.

Test practicalities

Use a pressure vessel for depths beyond a few metres, and hold for the declared time with the enclosure in the orientation it will be used. Record the temperature, because a warm enclosure tested in cold water is a harsher test than the reverse. After the test, allow the enclosure to reach room temperature before opening it, so that condensation does not get mistaken for ingress.

Related technical notes

• IPX9K: High Pressure, High Temperature Washdown
• IP5X and IP6X Dust Test: Talcum, Concentration and Duration
• Turntable Speed in IP Testing: Why 1 rpm Matters