Application as installation explosion-proof and endurance burning proof for certain flammable liquids of the explosion group IIA with a maximum experimental safe gap (MESG) > 0.9 mm and a maximum operating temperature of 60 °C. As venting and breather device for fixed roof tanks to prevent inadmissible pressure and vacuum and to minimize gas losses by variable pressure setting of the weight-loaded and/or spring-loaded valve devices. Installation of an explosion-proof condensate drain device is possible.