eli5 How do waterproof phones work? Why are most phones only waterproof for a certain period of time?
In: 7
There is no such thing as a waterproof phone. The components are just fit in tight enough that damage isn’t as likely being briefly submerged. These sensitive components and their will degrade and short electrically over a time after being submerged.
Modern phones use wax and tight-mesh technology to keep water out. It’s what makes the phone water resistant.
No phone is water proof, but you can essentially call a modern iPhone water proof because no, you’re not going to drop it 3 meters under water for half an hour
Waterproof is a marketing version of a specific standard, like Intrusion Protection IP67 in the case of the iPhone. This standard requires a specific test, 1m of water for 30 minutes with no failure. That defines the test that the company ran, not how waterproof the phone is. The lawyers make the marketing people mention these parameters (1m for 30 mins) because they want to avoid future lawsuits.
In fact, Apple might know the actual failure point of the average iPhone, as part of some destructive testing program. Maybe it’s 7m of water or 1m for 3 days. That’s not enough for IP68 (which I think requires 10m). So, no reason for Apple to tell anybody that.
As with many things, the devil is in the pedantic details.
Waterproof means fully impervious to water. Water resistant means it just can resist water.
In the case of phones, it’s resist. The methods like seals, gaskets, and a crap ton of glue are only able to be *rated* temporarily.
There are edge cases like “woman drops phone in lake, recreational divers find it and return it months later. Still works.” But for a company to claim something, it has to be repeatable to a certain degree. That degree and certification has time and depth standardized.
Everything is only water proof for a certain period of time, it just might not be a useful time scale
Water is tricky. Its really good at slowly sneaking its way through things and around things. The more time you give it and the more pressure behind it, the more likely it is to make it through.
Phones use an assortment of creative fits, seals, and hydrophobic (water afraid) materials to keep water out. The water will slowly start creeping its way in and around and over all of those defenses as no seal is 100% perfect so if it spends enough time in the water it will eventually make it in. Similarly, the seals only fit with a certain amount of pressure, if you were to take an iPhone down to the Titanic(3800 meters down), it would experience 380x standard pressure and the water would pretty quickly bust through any seals to get inside.
We test phones against reasonable occurrences. One of the standard Ingress Protection (IP rating) tests against water is 1 meter for 30 minutes and the device has to work afterwards. Its a reasonable timeframe to test and a depth your phone might encounter so most things targeted IP67.
There’s now a push for better protection specs so you’ll see more things rated to IP68 where the manufacturer can get certified for long time or greater depth. They still generally pick 30 minutes because that’s what the competitors are using and opt to prove it out at a deeper depth. A phone good for 30 minutes at 6 meters is definitely good for 30 minutes at 1 meter but might not be good for 3 hours at 1 meter due to the significant increase in time for things to slowly creep around the seals
Water resistance is created by effectively blocking up the holes where water can leak into the phone.
A lot of this is fairly simple to do, just awkward for various reasons. For example rather than having a back that sides off to allow you access to the battery compartment, the battery is sealed permanently inside, and rather than a loose rear panel that clicks into place, you have a much tighter fitting and glued panel that doesn’t have that slight gap around the edges. Or rather than just having an exposed button that water can leak around, there will be a rubber membrane between the button and case that stops the water leaking in around the button.
The reason for the different ratings you see mentioned is the way water resistance is tested. The deeper underwater (and therefore higher water pressure) and the longer the time spent underwater the more likely it is that water will be able to migrate in through the tiny gaps that are left in the case.
So we consider these two factors when we do testing to confirm water resistance – because of the fact that a higher water resistance rating is harder to reliably produce without defects, the manufacturers will choose a certain rating of depth and time, test their phones to confirm that they are capable of withstanding those values and pass them when they do.
Your phone may actually be capable of withstanding far greater pressures and times, but more phones will start to fail if they chase higher numbers, so a practical option is chosen instead.
Latest Answers