arpadveress 
The explosion-proof products, equipment installed elsewhere in the possible hazardous area Ex zone, other installations responsible for the explosion protection and the technical solutions for handling the effects of the explosion must be maintained in an explosion-proof manner until the explosion-proof technology exists.
Which means lifetime tracking of Ex installations is a must have for all Ex sites in terms of electrical / non.electrical installation and systems as a matrix of before mentioned Ex installations.
Keep up good work!
