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Designing a Waterproof Product With IP Ratings

The Big Picture: Manufacturers determine IP ratings, not an impartial group. Although useful for comparison purposes, they are not the panacea for rating electronic waterproof design.

Mallory McGuinness | March 25, 2020

If you are designing a waterproof product, and you are using IP ratings as a measuring stick, you may want to reconsider. When people think about IP ratings, what they normally understand as “waterproof” are IPX5, IPX6, IPX7, and IPX8. However, this is a misrepresentation. So why do we use IP ratings to measure the amount of liquid protection a device has?

Do IP Standards Measure Liquid Protection, or Are They Just a Marketing Measure?

Consumers have been demanding waterproof electronics for a while now, and in the past, manufacturing marketing teams were happy to deliver what they didn’t necessarily have. Marketing teams, for watches in particular, showcased the word “waterproof” in their messaging. But these watches couldn’t stand up to liquid submersion.

 

one phone underwater that is still working because of HZO protection and another that is dead because of water damage

In an attempt to clear the confusion, the International Organization for Standardization (ISO) replaced the word “waterproof” with “water-resistant.” This happened in 1990, when ISO issued the standard ISO 2281 for water-resistant products.

Nevertheless, a few years ago, commercials appeared with people using electronics in the shower, swimming with them in the pool, and dropping devices in the water – electronics, like smartphones, which again, weren’t waterproof.  

However, these commercials naturally led to the belief that the advertised products were, in fact, waterproof. However, customers described dropping so-called “waterproof” electronics for as little as 5 seconds, only to witness instant device destruction. The icing on the cake was that many manufacturers refused to mitigate liquid damage in their warranties.  

As you might have imagined, lawsuits ensuedISO tried to clarify again when they replaced the ISO 2281 standard with ISO 22810 to update the content in 2020. 

Now, the term “water-resistant” is used to describe products and the testing protocols qualifying them that were created by the International Electrotechnical Commission (IEC) and ISO. Let’s take a look at some of those protocols now so you can get an idea of just how “waterproof” IP rated devices are. 

What’s the Equivalent to IP Rated?

The first thing to know about IP testing protocols is that testing uses pure water only in laboratory conditions, while the device is powered off.

Additionally, IP ratings only test for very specific environments:

IP Ratings only test for very specific environments

  • Relative humidity range – 20% to 75%  
  • Air pressure range – 86 KPa to 106 KPa 
  • Test samples should be completely new and clean. 
  • Recommended temperature range – 15 C to 35 C 

After testing is complete, manufacturers inspect their devices’ enclosures for water ingress. Some water can even actually enter an enclosure and pass IP testing – under the condition that the exposure to water did not interfere with device operation or put user safety in jeopardy.

Do IP Standards Hold Up To Real Life?

Below are the requisites manufacturers must meet to deem a device “IP protected.”

The IPX6 standard test confirms that a device is placed at a specified depth (1 m) and can withstand freshwater for up to thirty minutes.  

The IPX7 test attempts to determine whether electronic enclosures can provide enough protection from temporary immersion in water. A device will be immersed in water for a half-hour. The temperature of the product and the water cannot vary more than 5 C.

IPX8 tests for continuous immersion and are completely subject to manufacturer’s requisites. In general, at least, they should be more severe than IPX7 conditions.

    The first thing to know about IP testing protocols is that testing uses pure water only in laboratory conditions, while the device is powered off.   

    So, it seems that if you are submerging a product out of the box into 1 meter of fresh water inside of a laboratory, your bases are covered. But what happens when you step outside the lab?

    If You Need a Completely Waterproof Device, the IP Rating System Won’t Help When Life Happens

    There are a few glaring problems when it comes to calling an IP rated device “waterproof” in real-life scenarios:

    • Device pressure is affected by how it enters the water for IPX7 and IPX8 tests. Fluctuations in pressure can affect the depth and time that a product can be submerged in water.
    • Temperatures in bathrooms, bathtubs, steam rooms, or saunas will probably exceed the specific temperature range that manufacturers test for, making the physical seals meant to protect electronics less efficient at protecting the device.
    • The tests use fresh water. Freshwater is in stark contrast to what the water that devices typically encounter, like tap water, swimming pools, saltwater, bathtubs, or toilets.
    • Chemicals commonly used like perfumes, oils, hair dyes, and solvents can eat away at the mechanical parts and seals protecting a product, dragging the water-resistance level down.
    • The fact that a device can be placed under 1 meter of water is great, but in the real world, products will probably fall to the bottom of the water, voiding the guarantee that water will not ingress.
    • The devices don’t have to be on during testing – if an electronic device is powered on underwater and is running programs, its internal temperature and pressure will increase, negatively affecting the depth of water the product can withstand.

    But what happens when you step outside the lab?  

    How to Design a Truly Waterproof Electronic Device

    If you want a waterproof (not “water-resistant”) device, you need Parylene conformal coating. As we explained above, commonly used mechanical seals don’t cut it.  

    Parylene is a polymer that coats the circuit boards powering your devices from the inside out. It doesn’t add thickness or bulk to devices that other conformal coatings do, and our Parylene can nullify water damage and last up to 20 years.  You can learn more about Parylene and our Parylene coating process here. 

    Not All Devices HAVE to be Completely Waterproof

     Although the IP rating standards are nebulous, they’re still useful for comparison, and many manufacturers require IP testing for devices that aren’t completely mission-critical. That’s why plasma-based nano coatings are sought out by engineers who are looking for affordable, ultra-thin conformal coating –  they can meet any IP rating reliably and with scale.  

    But we digress. So is IPX7 waterproof? The answer is no; it is just water-resistant. When you consider your mission-critical waterproof electronic design, remember that you aren’t building products for a lab, you’re building products for life on life’s terms.  

    If you want a waterproof (not “water-resistant”) device, you need Parylene conformal coating.

    Mallory McGuinness

    Mallory is an electronics protection evangelist who writes content for HZO. In her free time she is reading non-fiction, and hanging out with her beta fish, King Awesome.

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