The secret to waterproof phones

Sasha.shine.bright/Shutterstock.com

Ever wondered if your phone would still work if you accidentally dropped it down the toilet? Or left it out in the rain? Its ability to survive depends on its IP rating, which is defined in an international standard.

Many phones these days are water resistant to some extent, designed to withstand the occasional splash or even a very brief immersion down the toilet. But the precise level of their resistance can vary widely, and terms such as ‘waterproof’ or ‘water resistant’ give little information about how much water they will resist, at what pressure and for how long.

To help clarify this, the industry uses a rating system called the Ingress Protection (IP) rating.

IP ratings explained

An IP rating is the internationally recognised way of classifying the degree of protection provided by mechanical casings and electrical enclosures against dust and water. Defined in IEC 60529, it grades the resistance of a casing or enclosure against liquids or dust.

The rating is composed of two numerals. The first refers to the protection against ‘solid foreign objects’ such as dust, ranging from 0 (non-protected) to 6 (dust tight). The second refers to the ingress of water and ranges from 0 (non-protected) to 9 (protected against high pressure and temperature water jet.

For example, a phone with an IP rating of IP69 is one with the highest rating, meaning it is ‘dust tight’ and protected against high pressure and temperature water jets. One with an IP67 rating would be equally dust tight but only resistant against temporary immersion in water.

IP ratings in action

Many of the latest popular phone models are around IP67, IP68 or IP69. But this does not mean they are all made equally when it comes to water protection.

The standard defines the test methods and the IP rating defines its resistance at the time of testing, but not the overall quality of the phone, nor does it control how testing laboratories interpret each rating.

How a phone reacts when water gets into it can differ depending on the make and model, as can how long the device remains resistant, and it does not cover hot, salty or soapy water which could degrade the seals.

The standard does, however, provide a catalogue of internationally agreed test methods that is used widely around the world for a wide range of electrical and non-electrical products.