A firefighting installation includes a network of vacuum sprinklers. The installation incorporates a trip device that triggers the application of water to the network of sprinkler. The trip device includes: a master actuator sensitive to pressure present in the sprinkler network and capable of moving a yoke from a first to a second position; a lock for locking a member of the actuator in position; and a transmission member transmitting between the yoke and the locking means. The master actuator includes a membrane able to move between a first position corresponding to the sprinkler network being under vacuum and a second position corresponding to the sprinkler network being subject to atmospheric pressure, the first and second positions of the membrane corresponding to the first and second positions of the yoke.