IP codes used in radio

Ever see radios labelled with IP codes, such as IP55, or IP67? In this post I will explain what they mean and how they were derived.
IP stands for ingress protection, and it is a way of measuring how water and dust resistant a device is.

The first number in an IP rating signifies the dust or particle protection. 0 is none, and 6 (the highest) means completely dust proof, and no dust can get inside the device. In between, you have various sizes of particles ranging from 50mm down to 1mm, and then dust. Almost all radios will be able to get a 4 in this section, so a 4 or below is not a very good score to get. A 5 means that the device is protected from dust enough so that the dust will not affect its operation, and a 6 means that no dust at all should get inside the casing of the dust.

The second number tells you how waterproof or water resistant the device is. If you want a device that can withstand even the heaviest rain (without being submersed), then look for a 5 in this section.  The specification  to get a 5 is that water jets can be sprayed from any direction without any damage occurring to the device. With radios, that includes receiving and transmitting while being sprayed with jets.
For a 6, the specification states more powerful water jets, with a rate of spray of 100 litres per minute.
7 and 8 are the highest ratings that can be achieved, where 7 is immersion in 1 metre deep water for 30 minutes, and 8 is immersion continuously, at a depth stated by the manufacturer. Level 8 will generally not be used for radios, since 8 is only really needed for diving or underwater uses.

As an example of the IP rating used for radios, the Motorola DP3400 is supposed to be IP57. This means that no dust will enter enough to affect operation of the device, and it can be submerged in water at 1m for 30 minutes and will still work fine.