During an explosion in a container like a filter or silo, rupture discs prevent excessive pressure from building up. If the response pressure is exceeded during an explosion, the rupture discs will rupture in a controlled way. It is important that no parts fly out in the process. Flames will escape from the released opening in a range extending from a few metres to up to 60 metres due to the overpressure in the container, causing pressure effects in the external area.

The letter Q stands for "quenching". Like conventional venting, a rupture disc is also used but unlike other options, it has a downstream stainless steel mesh cage, which extinguishes any flames escaping as a result of the explosion. The pressure effects in external areas are significantly reduced.

This option also requires a defined opening surface on the container that will be released in the event of an explosion. In this case, the venting mechanism is a damper blade, which springs open if a defined response pressure is exceeded. After an explosion, the damper blade returns to its original closed position by the force of gravity.