arpadveress 
Primary – Secondary – Tertiary explosion protection
So far we can say it is all about prevention.
Primary: prevention like how to avoid the presence of hazardous material…
Secondary: prevention like how to avoid presence of ignition sources…
Tertiary: prevention like how to avoid any harmful consequence of a blast or similar…
Picture gives a good indication: partial we can be successful here and the remaining dangers we shall cover with the next possible protection layer.
All 3 shall be with importance for the complete technology in possible hazardous environment. Completeness shall be with all presence there.
Keep up good work!
Arpad
This is the kind of apparently useless data that I like to know about. Zebra pattern functionality was previously explained as a sort of camouflage. The black and white bands were widely used i the I and II World Wars. Especially on ships. The argument was that the Zebra pattern disrupted the sense of perspective, thus altering the perceived geometry of the object.
I wonder if the crews of ships painted with the Zebra pattern in WW II suffered less from mosquitoes in the Pacific theatre.