In the art of fortification blast valves have major applications. Openings in a defence structure are potential weak points. To obtain a balanced hardening of a structure it is essential that the openings provide protection at the same level as the rest of the installation. Whether there is a threat of nuclear (long duration) blast or blast from conventional weapons - which might be of short or long duration depending e.g. on geometry - there exists a great number of valves for different applications and protection levels. The Research Department of FortF applies special test procedures for valves using a high-explosive driven shock tube. Varying the charge yield and the distance between charge and object facilitates modelling of the impinging shock wave within certain limits. For some testing applications the tube is open in the rear end resulting in a suction phase succeding the overpressure as in a real case. The paper describes different kinds of blast valves and their applications for protective structures and gives examples of testing procedures.