All has its sources of origin and informations.
Product Ex certification: ISO 17065
Ex personnel competency: ISO 17024
Ex design, Ex installation, Ex inspection, Ex maintenance and repair: ISO 17020
If we say, we do Ex – we shall mean we follow those ISO standards as well. Validation of Ex shall always refer to.
Keep up the good work!
Arpad
In case of hazardous are compliance we shall not make any difference
A possible ignition source: your shoes in potential hazardous environment
#exprofessional
Inspecting a non-electrical device with Ex h (explosion-proof) protection method in a
The main environmental factors which may affect the equipment intended for use
arpadveress 
