The media is a buzz about the new iPhone 7 and its water resistance. In the hearing aid industry, they have been employing the same technology for several years to prevent water and perspiration from damaging sensitive electronics. How do they do this?

A nano-coating is essentially a microscopically thin film that’s sprayed over the internal components to help water roll away from anything that could potentially be damaged by moisture.

Waterproof vs. Water Resistant
There is only one hearing aid rated as “water proof” – the Siemens Aquaris. It can be submerged up to 3 meters with an appropriate ear mold that prevents water from entering the tube. It is available in only a behind-the-ear style. The rating is IP68. What does that mean? Hearing aids have adopted the same system as many other consumer electronics at rating their water-resistance.

Rating System
IP ratings – what do the letters and numbers stand for?
IP ratings are made up of four characters.

The first two characters, I and P, stand for Ingress Protection or – in other words – how good it is at stopping stuff getting inside it. The third digit is the number that indicates how good it is at protecting against small solids (dust/sand etc), with a maximum rating of 6. This ranges from no protection at all, through small screws, a little dust or all dust.

The last digit is the liquid or water resistance rating, with a max rating of 8.

In other words, if you see IP68 somewhere, you know it offers the highest IP rating for both dust and water resistance. At least, when it comes to the IP-rating certification.

What does IP67 mean?
The hearing aids that I fit (other than the waterproof) are rated IP67. There’s a large number of combinations when it comes to IP ratings, and it can get confusing. IP67 devices, like the iPhone 7 and iPhone 7 plus, for instance, have the same dust resistance as the IP68-rated Siemens Aquaris, but can only survive being up to 1 meter deep in water. Any more than that and the water could push through any protection in to the internal components of the device.

It’ll come as some relief that the “6” also means it’s good with deliberate contact with a body part, so it won’t crumble like a Jacob’s Cream Cracker when you pick it up.

IP = Ingress Protection
6 = Dust Tight
7 = Survives being submerged in water up to 1m deep (normally for 30 minutes)
It’s probably worth noting, just because something is IP67 rated and great at lasting underwater, it may not be tested to withstand rain or spray from a jet of some kind.

Keep in mind that the test is taking place once in a lab with a new device, not repeatedly over a period of years. Hearing aids are frequently exposed to sweat, rain, and dust on a regular basis. The better the rating hopefully the greater the durability. That still means due care is needed to prevent exposure for long term reliability.

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