The ATEX classification system classifies equipment and protective systems intended for use in explosive atmospheres into two main categories:

Equipment group (II), which is further divided into two categories:

+ Category 1 equipment is intended for use in Zone 0, Zone 1, or Zone 2 locations where explosive gases or dusts are present continuously, frequently, or for long periods.
+ Category 2 equipment is intended for use in Zone 1 or Zone 2 locations where explosive gases or dusts are likely to occur only occasionally.
+ Temperature class (T1, T2, T3, T4, T5, T6) refers to the maximum surface temperature of the equipment under normal and abnormal conditions. This classification system is based on the expected maximum surface temperature of the equipment when it is in use and in the event of a fault.

In addition to the equipment group and temperature class, the ATEX classification system also includes additional codes and markings that provide information about the specific requirements for explosion protection that the equipment or system must meet. For example, equipment may be marked with codes indicating the type of protection that has been built into it, such as "d" for flameproof enclosures or "e" for increased safety.

Another important aspect of the ATEX classification system is the requirement for regular inspections and testing of equipment and protective systems. This ensures that the equipment remains safe to use and that any potential issues are identified and addressed in a timely manner.

It's also worth noting that compliance with ATEX does not guarantee that the equipment will be safe in all circumstances; rather, it's a guarantee that the equipment has been designed and manufactured to meet certain safety standards and that it has been tested and certified to be suitable for use in explosive atmospheres. Therefore, the equipment must be used in accordance with the instructions and guidelines provided by the manufacturer and the local regulations.

It's important to note that the equipment and protective systems must be marked with the appropriate category, temperature class, and zone they are suitable for.