The IP code that comes in connection with your chosen radio may be somewhat of a confusion to the average user. The official meaning behind this code is to classify the degree of protection your radio has against intrusion, covering things such as dust and water immersion for set periods of time.
The two digits following the IP both stand for protection against different substances, for example the first number is in terms of solids that your radio may come into contact with, whilst the second being in relation to water. Solids range from a rating of 1 through 6, whilst water is protected from a rating of 1 through 9K. Should a digit of 0 appear in either the solids or liquids position, then this indicates that the radio is not protected against said material.
Radios without an Ingres protection would be IP00, although this is extremely rare for a two way radio to have no Ingres protection, with the most common protection rating from manufacturers such as Motorola and Hytera being IP54. This covers the radio for a limited Ingres protection against dust, whilst also being safeguarded against splashes of water from all directions.
ATEX radios are designed to be used in some of the most dangerous working conditions in the world, environments such as mining, oil refineries and power plants are common places for these types of two way radios. Due to the high level of danger in place, the IP rating tends to be higher at IP67. This rating not only conceals the radio completely against dust, but also protects the radio from immersion in water up to 1 meter deep for around 30 minutes.
Differentiating working environments will determine the level of Ingres protection you will need for your radios, for example in an education environment purchasing radios that are IP68 rated would be completely unnecessary, where radios that are IP54 would be the more logical choice. Leisure centres can be dependent on the fact of if there is a swimming facility, should this be the case then a radio that is IP67 and protected against immersion in water would be a better fit.