This post also appears on the Clove Technology Blog
When looking at a new smartphone or other item you may have seen an IP rating advertised: IP67, IP68, IP57 or IP58.
IP stands for Ingress Protection. The numbers denote how well a product is resistant to solid objects / particles and liquids.
The first digit is in the range 0-6 and the second ranges from 0-8. Most products that are advertised as rugged fall into to 57, 58, 67 or 68 categories, however others are still fairly common.
An 'X' can be substituted for one of the digits if there is only one class of protection; i.e. IPX4 would address splashed water resistance only - the product may not have been tested for solid objects.
The first digit recognises the mechanical protection as detailed below:
The second digit illustrates the the level of water ingress protection the device offers, as detailed below:
When put together these ratings indicate how well the device is protected from foreign bodies and water.
Some older phones or wearables may have lower ratings such as IP54 or IP55 where they can withstand splashes and rain but haven't been designed to be completely immersed in water or used in severely dusty environments such as deserts.
The difference between 7 and 8 on the liquid scale is subtle but important. 7 is "Protection against immersion" whereas 8 is against "complete, continuous submersion".
Immersion could be considered a quick drop into a body of water such as a puddle or toilet bowl. Where an X8 rating is given, you could effectively leave the phone underwater for a continued time. You'll often see adverts that describe up to 2 metres for 30 minutes.
A cheap way to offer an IP rating is to cover sensitive areas with rubber plugs and seals. This includes charging ports and headphone sockets. Invariably these covers create the required rating, but can frustrating if you have to regularly pop them open.
Newer (and generally more expensive) IP rated phones have opted to cover sensitive areas with a water-resistant (hydrophobic) coating.
You'll see this on the newer consumer-oriented phones from Samsung and Sony where the design and fashion of the phone are important. You can also buy these yourself in the form of Crystalusion Liquid Glass.
More trades-oriented phones from Cat, DeWalt and Defender tend to use rubber seals or screw in plastic. These are less likely to fail in extreme conditions. Nano-coated ports also need to dry before they can be used safely.