The propagation of the explosion from a part of 'protected' plant to another 'non protected' part via the connection piping (e.g. pneumatic conveyors) takes place in many cases and is necessary to guarantee the protection and safety of the staff that work in the adjacent area through the use of Decoupling Systems (prescribed by EN 1127-1) to prevent the explosion propagating through the pipes that connect the equipment in question to the rest of the plant. The block valve is studied, designed and tested especially to safely partition the production rooms from the filters.