IP and more
IP rating is a measure of how protected the mobile phone is against water and dust. This is what the numbers stand for.
The IP rating is given as IP and two numbers. The first number is a measure of protection against gravel, sand and dust. The higher the IP class, the smaller particles the mobile phone is protected against. This is probably something that most people don’t worry too much about. We don’t expose the phone to sand if we can avoid it altogether, regardless of what the enclosure class says.
The second number is the one that interests us here because it is the measure of water protection. Each level means that the device passed a test where it was exposed to water. This is what the scale looks like.
IPX1: Water drips vertically over the test object for 10 minutes (equivalent to 1 mm of rain per minute).
IPX2: 15° obliquely incident water drops fall on the test object for 10 minutes (equivalent to 3 mm of rain per minute).
IPX3: Water is sprayed over the test object for 5 minutes at 0.7 liters per minute with a pressure of 80 – 100 kPa.
IPX4: 10 liters of water per minute are sprayed over the test object for 5 minutes with a pressure of 80 – 100 kPa.
IPX5: 12.5 liters of water per minute are flushed towards the test object from a distance of 2.5 to 3 m for at least 3 minutes.
IPX6: 100 liters of water per minute is flushed with 100 kPa pressure against the test object from a distance of 3 m for at least 3 minutes.
IPX7: 30 minutes immersion to a depth of 1 m
IPX8: Immersion in water depth and time specified by the manufacturer, but more than required for IPx7.
IPX9: Water that is flushed at high pressure around the entire object must not have a harmful effect.
IPX9K: Same as above but with water temperatures of 80 degrees.
In addition to these classifications, there is also pressure classification, which is mainly used for watches. This means that they are airtight up to a certain pressure measured in atmospheres. In practice, we are interested in liquid pressure here, and one atmosphere corresponds to a depth of ten meters in water. 5ATM, which is the most common rating, corresponds to the pressure from the water at a depth of 50 meters, and the device must handle it without taking in water.
If you look at these classes, you can perceive that already IPx1 makes the phone resistant to rain, at IPx7 you can swim with the phone without risking damage, and a watch with ATM5 you can use when diving with tubes. It’s wrong. These tests are performed in a lab environment with very strictly defined test methods. The reality is much messier. For example, if you have the phone in the rain, not only will water drops fall on it at different angles, the drops will also stay and rub against the phone with some pressure if you put it in your pocket. The underwater tests are carried out on phones that are slowly submerged in still water, which is different from swimming with the mobile phone as the phone is exposed to moving water with a completely different force. The fact that a phone can withstand 30 minutes at a depth of 1.5 meters under water, which most mobile phones with IP68 class can handle, does not mean that it is guaranteed to withstand that you drop it in a pool and it lands at a depth of 1.5 meters, because it is not certified to withstand the journey to the bottom in that way.
This tip comes from an article where we went over how waterproof your phone actually is, with explanations of IP rating and military certification. The article that you will find in its entirety here was previously published exclusively for Plus members at Mobil.se. Here you can become a Plus member and thus get direct access to all articles on Mobil.se. As a plus member, you get collected tips and many other in-depth, guiding articles.