IPX9K: High Pressure, High Temperature Washdown

IPX9K is not part of IEC 60529. It comes from DIN 40050-9 and is widely referenced by automotive and food processing specifications for equipment cleaned with high pressure steam.

The conditions

Water at 80 degrees Celsius, delivered at 80 to 100 bar, at 14 to 16 litres per minute, from a nozzle held 100 to 150 mm from the surface. The jet is applied at four angles: 0, 30, 60 and 90 degrees, for 30 seconds at each, with the sample rotating at 5 revolutions per minute. The pass condition is no water ingress that could be harmful.

Why it is brutal

The combination of pressure, temperature and proximity defeats most elastomer seals. Materials that survive IPX6 at room temperature soften at 80 degrees and take a permanent set, so the seal leaks after the test even if it held during it. Vent paths and label adhesives also fail.

Specifying it

If the cleaning procedure really uses a steam lance at close range, specify IPX9K and test with the actual nozzle. If the cleaning is a low pressure hose, IPX6 is the honest requirement, and IPX9K adds cost without benefit. Do not accept an IPX9K claim without the distance and angle used in the test.

Related technical notes

• IP5X and IP6X Dust Test: Talcum, Concentration and Duration
• Turntable Speed in IP Testing: Why 1 rpm Matters
• IPX4 or IPX5: Choosing the Right Water Level