arpadveress 
Primary Ex is about prevention.
Secondary Ex is about protection.
Tertiary Ex is about follow up action, how to mitigate the consequences of possible explosion.
just received the question: if there is a well engineered gas sensoric and ventillation system, is there any need for tertiary Ex? is it a good question? what about secondary? what about any management issues to co-ordinate explosion protection on site?
is one of them simply enough?
my answer: No. in all cases all 3 shall be considered, but maybe not applied. it depends on many factors: 1) Ex personnel competency (understanding of epxlosion protection) 2) HAC (hazardous area classification) 3) …
what is Your comment to here?
previous exprofessional.com post to here: link
Keep up good work!
