A Panasonic survey from 2018 has shown that a lot of professional customers don’t know what an IP rating stands for. 40% believe the X in IPXY is a rating for energy efficiency.
Although ruggedness is seen as an important requirement, the terminology is confusing. You don’t need to become an expert though. Here are the 2 most important standards.
IP rating by the International Electrotechnical Commission (IEC60529)
The IP rating is a standard for ingress protection. The first digit stands for solid particles, the second digit for liquids.
Most rugged devices are between IP54 and IP68.
It is not only that a higher number is better. A device with IPX8 (immersion in water) may actually fail a water jet (IPX6). So, it depends.
Many smartphones are IP rated nowadays. They have gone through the same laboratory tests as a “rugged” device. Rugged devices have a much more robust design. There is simply more material and it does not rely on a hydrophobic coating. This coating may lose its effectiveness over time. Apple actually denies warranty cover with liquid ingress. IP rating for phones is a great thing but it's not designed for the same durability.
Which IP rating should you buy? Well, make sure you have an IP rating. IP54 is the basic level to claim ruggedness. IP X8 means you can theoretically dive with it (1m). But why would you? You can accidentally drop the device into water, you can wash it in a puddle of water if it got dirty, and you know for sure you can work in rain. Not once, but over the life of the product. And that’s the difference between smartphone IP rating and rugged device IP rating.
MIL-STD by the United States Military
Military standard. That must be rugged!
The MIL-STD for “ruggedness” is -810. There are many other MIL-standards. There is a tiny difference in what manufacturers state: Tested to MIL-STD or simply “MIL-STD” or “designed for…”. Products can be designed for MIL-STD-810 without even being tested for it. It’s also important to note that the tests are also laboratory tests only.
The MIL-STD-810 is a good assembly of tests to confirm the product is rugged as long as the tests are done p[roperly and preferably by a certified laboratory.. If you want to be really sure what exact test is used you’d need to look up the test, the method, the procedure, the category and also the version of the revision, but that means you become an expert. Therefore: If the manufacturer is specifying vibration, then that means someone was at least thinking about vibration. The test should also be done by a certified laboratory.
An example highlighting some of the dependencies are drop tests. The test is mostly done dropping the device on all edges, faces and corners. If in real life the device is dropped and hits a rock with the display, it will probably break. The drop test can refer to MIL-STD-810. However, there are no drop tests for GNSS receivers in the MIL-STD. Here the manufacturer should provide a 2m pole drop test although there is no standard for that. It can still be aligned with MIL-STD tests though.
The most common tests are: Operating and storage temperature, drop, humidity, vibration, and altitude.
At the end of the day it’s a decision as to whether you trust the manufacturer that they comply with the standards being claimed. It’s good practice to state to what standard the test has been done (e.g. IEC60529 or MIL-STD-810) If standards are claimed it is likely that the product will indeed meet and exceed or at least get close to that standard.
There are plenty of other certifications like RoHS, WEEE, FCC, CE, REACH. These are regional environmental or regional safety certifications.