How do IP65, IP66, IP67 and IP69K differ? Can a Panel PC rated IP65 at the front be hosed down?

An IP code has two digits under IEC 60529. The first is dust protection, where 6 means fully dust-tight. The second is water protection: 5: withstands water jets from a small nozzle in any direction. 6: withstands powerful jets from a larger nozzle. 7: temporary immersion up to 1 m for 30 minutes. 9K: close-range high-pressure, high-temperature jets, used for food equipment washdown. A common mistake: the levels are not cumulative in the sense of a higher number being better in every way. A device rated IP67 (immersion) may not withstand IP66 powerful jets, which is why many devices carry dual ratings such as IP66/IP67. For a Panel PC rated IP65 at the front: it tolerates splashes and wet wiping on the front when correctly mounted in a cabinet door. Do not aim high-pressure or hot water directly at it, and the rear is not protected to that level. Pressure washdown areas need a fully sealed unit with a suitable IP rating.