This week I'm thinking about waterproofing electronic devices. Many products today are designed to survive being dropped, dunked, or damaged. How does waterproofing criteria feed into the design cycle? This can be tricky. Sometimes a spec creeps in and adds significant design work to a development project.
Should I define ingress protection rating? Devices that carry an official IP rating are certified to be resistant to dust and water ingress. The IP rating system is a quantitative measurement of the protection level a device has to dust and water. It gives a measurable value to the marketing terms like 'waterproof' or 'dustproof' Devices that carry the certified rating have been tested in a laboratory setting, under controlled conditions, and proven to meet or exceed these standards as defined by the IEC. Read carefully though. Some devices say something like, "conforms with IP68 standard" but they do not bear the cost of certification. Also, many OEMs will certify their device to be IP67/IP68 but won't warranty their device for water damage. Why? Once the device leaves the factory, there's no telling what a customer will do to their device. So the rating becomes a selling point only, a bit of insurance against accidental submersion. Sometimes it's an irrational spec war User-needs or market requirements will drive the addition of an IP certification. "We want to meet or beat the competition which has IP67...so let's go to IP68 on our device!" (for reference, IP67 is 1-meter submersion for 30 min, IP68 is 3-meter submersion with no defined time limit) The challenge with this type of thinking is that a higher IP rating doesn't necessarily serve the end customer. It's an irrational spec war that can't be won. What's higher than IP68? I'll tell you: IP69/K. That's it. That's the top of the heap. The certification doesn't get any higher than IP69/K. It will take a dedicated effort to move a device designed for IP67 to IP68, and a significantly higher effort to hit IP69/K. IP69K is high-pressure, high-temperature water blast. There's few reasons to certify your device for IP69/K, unless you're building electronic equipment for the inside of a car wash. Or a dairy barn, or vehicle electronics that get blasted with a pressure washer.
But my watch says 30m, 3atm, Water Resistant... This is where ingress protection ratings can get really confusing. The diver's watch Water Resistant Rating is a totally different rating system Watches have their own rating of test pressure, but it's NOT a waterproof rating. The watch rating is only a static pressure test that's performed ONCE during manufacturing of the device, and is in no way a certificaiton of what that device is capable of under normal use. Be careful when comparing apples to oranges. As you're defining requirements for your next product, consider matching the ingress rating to the real user needs. At COVE Design, we help product designers take a product idea and engineer it for manufacturing. We specialize in solving complicated design problems in the consumer electronic and medical device spaces. Send me an email if you're looking for help, or if you want to consult on IP design or testing methods.