IP55 sits between two ratings that actually appear in Robustbook's range, IP53 and IP65, which is probably why it rarely gets specified on its own and instead gets assumed to be some kind of midpoint. That assumption is wrong on both counts: the second digit 5 is a genuinely different test from the 3 or the 4 that come before it, and the first digit in an IP55 rating stays at a level that many buyers rate higher than it deserves. This article explains what actually changes between digit 4 and digit 5, where the real weak point of the class sits, and which devices in the range do not reach it.
The two digits after IP are defined independently in DIN EN 60529 and tested separately: the first covers contact and foreign-object protection, the second covers water. In IP55, the first digit 5 stands for complete protection against contact and against dust in harmful quantities. The second digit 5 stands for protection against a water jet from a nozzle, from any angle.
Anyone reading IP55 tends to focus on the second digit first, but the actual gap to many rugged devices in the range sits in the first. The 5 means dust-protected: dust may still get in, as long as it does not affect function or safety. Dust-tight, meaning no dust ingress at all, only starts at digit 6. On a device that works for years on a dusty construction site or in a sawmill, that gap becomes noticeable, because fine particles that are allowed to enter under IP55 accumulate over time in vents, keyboard openings and connectors.
Between the second digit 4 (IP54) and the second digit 5 (IP55) sits a change in test method, not just an increase in the amount of water used. For digit 4 the device is sprayed; for digit 5 it is aimed at directly with a 6.3 mm nozzle, delivering 12.5 litres per minute at 30 kilopascals of pressure from a distance of three metres, for at least three minutes, from every direction. In practice, this means an IP55 device withstands a garden hose or a wash station; an IP54 device is not built for that.
The difference shows up most clearly during cleaning. An IP54 device can stand in the rain but should not be hosed down; an IP55 device can. For workshops where devices get routinely hosed off rather than just wiped, the second digit 5 is the threshold that matters, not the 4. The first digit stays identical across both classes: dust-protected, not dust-tight.
No. An IP55 rating covers protection against a directed water jet, not against submersion. A device dropped into a puddle or a bucket of water is not covered by this test at all. "Waterproof" in the sense of submersible only begins at the second digit 7.
On the second digit, IP55 and IP65 should not be confused with each other: both stand for a water jet from any angle, tested with the same setup. The difference sits entirely in the first digit, since IP65 is dust-tight and IP55 is only dust-protected. For water, the two classes are equal; for dust, a full step separates them. The complete digit-by-digit table is in the article The Different IP Protection Classes.
No simple ranking applies here either. IP67 tests 30 minutes of submersion at one metre depth, not a water jet. A device rated IP67 has not necessarily gone through the water-jet test, and a device rated IP55 is not automatically fit for submersion. Anyone who needs both types of protection has to find both markings on the datasheet.
The most common disappointment with IP55 devices has nothing to do with water at all. After years in service, users occasionally report dust build-up around fans or port covers, exactly what the first digit 5 permits in contrast to the 6. For environments with sustained heavy dust, such as sawmills, cement plants or dry construction sites, the first digit 6, dust-tight, is the criterion that actually matters, not the second.
Of the 45 documented laptops and tablets in the range, 35 meet the IP55 requirement, exactly the same 35 devices that also meet IP65. Every one of them already carries a first digit of 6, dust-tight, which automatically covers the first-digit-5 requirement, and most of them add water-jet protection from any or a reinforced angle on top of that. A dedicated table for these 35 devices would only repeat what the article IP65 Rating Explained already lists in full, alongside the Laptop Comparison Table and the Tablet Comparison Table. The remaining 10 fall short, for two different reasons: five are rated IP53 or IP5X and do not reach the second digit 5 at all. Five more are rated IP67, dust-tight and tested for submersion, but without a documented water-jet test, which is why they do not formally count here, even though in practice they would likely withstand a water jet too. What that IP67 group does cover is detailed in the article IP67 Rating Explained.
| Device | Display | Rating |
|---|---|---|
| Durabook S14I | 14.0 inch | IP53 |
| Durabook S15 | 15.6 inch | IP53 (optional) |
| Durabook S15AB | 15.6 inch | IP5X |
| Getac S410 G5 | 14 inch | IP53 |
| Getac S510 | 15.6 inch | IP53 |
| Fieldbook F57G2 | 5.7 inch | IP67 |
| Fieldbook N101 | 10.1 inch | IP67 |
| Fieldbook N80G2 | 8 inch | IP67 |
| Getac ATEX EX80 | 8 inch | IP67 |
| Getac ZX80 | 8 inch | IP67 |
For water, yes. For very dusty environments, with a caveat: IP55 withstands rain and hosing down, but unlike the dust-tight digit 6, it allows small amounts of dust in over time.
Both digits apply independently. A device rated IP65 has passed the same water test as an IP55 device but is tested more strictly for dust. A higher first digit does not automatically improve water protection, and the reverse is also true.
Yes, that is exactly what the second digit 5 covers. A pressure washer is not covered by this test; that would require a higher digit or IP69K.
Yes, for water: the second digit 6, powerful water jets, includes the 5. For dust, IP66 and IP55 are not equal at the first digit, since IP66 is dust-tight and IP55 is only dust-protected, so an IP66 device exceeds IP55 on both digits.
If you are weighing IP55 against a dust-tight class for your own environment, the Robustbook team can help you match the rating to the actual conditions on site.