{"id":2118,"date":"2022-09-01T21:46:25","date_gmt":"2022-09-02T04:46:25","guid":{"rendered":"https:\/\/www.fictiv.com\/?post_type=cpt_blog&p=2118"},"modified":"2022-09-09T07:00:05","modified_gmt":"2022-09-09T14:00:05","slug":"nothing-gets-in-waterproof-enclosure-design-101-and-ip68","status":"publish","type":"cpt_blog","link":"https:\/\/www.fictiv.com\/articles\/nothing-gets-in-waterproof-enclosure-design-101-and-ip68","title":{"rendered":"Nothing Gets In: Waterproof Enclosure Design 101 (and IP68)"},"content":{"rendered":"\n

Remember going through National Geographic magazines from 30 years ago? I spent hours poring over images of life at the extremes: expeditions in glacial caves, Amazonian insects, Saharan dust storms, and underwater coral. But for my young nephew\u2019s generation, pictures are too static, largely due to one innovation: GoPro.<\/p>\n\n\n\n

A GoPro is a drop-proof, waterproof video camera most often used to capture the most mundane aspects of people\u2019s vacations, but is also used by semi-pros to capture underwater video and crazy adventures. Given the beatings I\u2019ve seen GoPros take, I\u2019m really impressed by the robustness of the GoPro\u2019s housing design and how foolproof the seals are.<\/p>\n\n\n\n

Whether or not you\u2019re making the next breakout electronics product, waterproof enclosures are used in all types of industry, from oil fields to iPhone cases. In this article, we\u2019ll explore the design aspects necessary to make sure you never ruin your company\u2019s four-thousand-dollar prototype again.<\/p>\n\n\n\n

Before diving in, we need to establish what the term \u201cwaterproof\u201d means, because it\u2019s subjective. For example, a smartphone case designed to keep rainwater from ruining a $1000 smartphone has different requirements than an electronics housing for monitoring deep-sea drilling equipment. So, how waterproof is waterproof enough for your application?<\/p>\n\n\n\n

The International Protection (IP) Marking System<\/strong><\/h2>\n\n\n\n

The International Protection (IP) marking system is the generally accepted method for evaluating electronics housings that\u2019s also called the Ingress Protection marking system. It gives concrete meaning to the term waterproof by using standardized tests that must be passed to achieve different levels of waterproofness. The system has two unrelated numbers following the IP: The first number indicates the level of dustproofness, while the second indicates waterproofness. <\/p>\n\n\n\n

If you want to only indicate the level of waterproofness, an \u201cx\u201d can be used in place of the first number. For example, IPx7 means we know how waterproof the enclosure is, but we neither know nor care about its dustproofness. <\/p>\n\n\n\n

The higher the IP rating, the better the sealing design of the part\/product. For instance, a product with an IP67 rating has much higher protection against the elements than a product with an IP14 rating. You can see the full spectrum of rating numbers below: <\/p>\n\n\n

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\"IP65\"<\/figure><\/div>\n\n
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\"IP<\/figure><\/div>\n\n\n

For most applications, the lowest rating considered \u201cwater resistant\u201d is IPx4. This describes many older watches and means that the interior parts will keep working after a splash of water, but any more water will be an issue.<\/p>\n\n\n\n

IPx5 is decent step up \u2014 if you spray your housing with water from any angle, the interior parts keep working. However, this level only stays waterproof if the spray is light, or just over 4 psi and relatively low flow. IPx5 is a good level for a \u201crain-proof\u201d housing, which is why a lot of phone housings come from the factory with this level of waterproofing.<\/p>\n\n\n\n

At IPx6, the testing is more intense. A housing must remain waterproof for several minutes with a 100-liter-per-minute jet at 15 psi. Most consumer electronics can\u2019t survive this test, and if they can, their designers are bragging about their \u201cIP Rated\u201d product.<\/p>\n\n\n\n

\"most<\/figure>\n\n\n\n

At IPx7, the test requires immersion in a meter of water for 30 minutes. If this test goes wrong, it goes really<\/em> wrong, and you end up with scrap electrical parts.<\/p>\n\n\n\n

Pro-tip: Just because your housing can withstand the static pressure of water at a one meter depth doesn\u2019t mean that it can withstand the water jet test from IPx6, so test both if the design will need to resist forceful spray.<\/em><\/p>\n\n\n\n

With IPx8 we reach the level of a GoPro\u2019s housing. An IPx8 rating means that your housing can withstand long-term immersion in water of some specified depth \u2014 for GoPro, that depth is 60 meters. At that depth, the housings are guaranteed to stay sealed at a pressure of 87 psi \u2014 incredible!<\/p>\n\n\n\n

At IPx9, the tests focus on close-range, high pressure and high temperature spray downs. At this level, the enclosures start having esoteric specialty designs, and it\u2019s not difficult to imagine standard sealing mechanisms failing. <\/p>\n\n\n\n

So, now that you know what the levels of waterproofness are, the question remains: How<\/strong> do you create a seal that withstands those tests?<\/strong><\/p>\n\n\n\n

The NEMA Rating System<\/strong><\/h2>\n\n\n\n

The National Electrical Manufacturer Association (NEMA) created a rating system that determines how protected a product is by determining the product’s ability to withstand exposure to oil, corrosives, snow, and other elements. Unlike the IP rating system, NEMA is mostly used in industrial applications and deals with more than just protection from water and dust. <\/p>\n\n\n\n

To use the NEMA rating system<\/a>, you must first determine if the product is to be used indoors or outdoors. Next, you determine which elements the product may encounter, whether the product will be hosed down, and finally, if the product will be exposed to corrosive agents, oil, or coolant. <\/p>\n\n\n\n

According to the system, for indoor use you can have a rating between 1 and 13, which correlates to an increase in protection against elements found indoors. Like the IP system, the higher the rating, the better the protection. For outdoor use, there are ratings of NEMA 3, 3R, and 3S. NEMA 4 correlates to products used in conditions containing high-pressure water, such as washdowns. <\/p>\n\n\n

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NEMA ratings requirements <\/em>(Source<\/a>)<\/figcaption><\/figure><\/div>\n\n\n

Designing Functional Seals <\/strong><\/h2>\n\n\n\n

Though there are nearly an infinite number of different types of seals, three of the most common are face gaskets, static o-ring seals, and dynamic o-ring seals. I\u2019ll cover each briefly, but if you want to really dig into the depths of o-ring design, the Parker O-ring Handbook<\/a> is one of the best (and most boring!) resources on the subject. <\/p>\n\n\n\n

One of the great things about o-rings is that they\u2019re a well-known technology \u2014 the recommendations haven\u2019t changed in 50 years \u2014 so they\u2019re sure to keep your design waterproof.<\/p>\n\n\n\n

Static O-ring Seals<\/strong><\/h3>\n\n\n\n

Static o-rings applications represent an ideal scenario: The connection you\u2019re trying to seal is more or less round, convex, and the two mating parts will stay together forever (unlike Brad and Angelina, *sigh*), or will at least be mated most of the time.<\/p>\n\n\n\n

O-rings come in a wide variety of sizes, denoted by the \u201cdash\u201d number. And no, o-rings aren\u2019t sprinters \u2014 the dash number is an ASTM designation that indicates a standard size (chart here<\/a>). Generally, the larger the last two numbers, the larger the o-ring ID (inside diameter), while a larger first number indicates a larger cross-section diameter.<\/p>\n\n\n\n

\"o-rings
\u200d\u200dO-rings come in many sizes, but only one shape. <\/em>(Source<\/a>)<\/figcaption><\/figure>\n\n\n\n

When using an o-ring as part of your seal design, you\u2019ll need to design a groove where the o-ring can sit. Groove designs remain essentially the same whether you\u2019re sealing two faces, a screw thread, or even a square peg in a round hole (Ok, maybe the last bit isn\u2019t true, but the first two definitely are\ud83d\ude09). <\/p>\n\n\n\n

For the design, you need only to consider 4 elements: <\/p>\n\n\n\n