arpadveress 
all who apply for any electrical/non-electrical project in any potential hazardous industry shall be Ex competent. that is not a question, that is fact. there are good brands of Ex personnel competency on the market. Ex personnel competency shall be refreshed within 5 years. this is the practice.
what about actual (theoretical/practical) knowledge? shall it be measured?
Ex knowledge shall be actual. continuous refreshment of knowledge is the minimum requirement of all hazardous area owners, they want to be sure: not only fancy papers people are equipped with, but actual knowledge is there too. it shall be measured and confirmed.
good topics are selection of proper Ex equipments based on zoning, glanding, …
Keep up good work.
Arpad
exprofessional.com
