Sprinkler system with a pre-action sprinkler head

A sprinkler system for installation in a building, the building comprising a room to be protected by a double interlock pre-action sprinkler head, the system comprising:

• a source of a fire suppressant fluid outside the room;
• a sprinkler system piping in fluid communication with the source of the fire suppressant fluid;
• and
• a plurality of sprinkler heads fluidly connected to the piping for receiving the fire suppressant fluid from the piping, the plurality of sprinkler heads comprising the double interlock pre-action sprinkler head inside the room to be protected,
• wherein each double interlock pre-action sprinkler head comprises
• a conduit inside the room having an inlet fluidly connected to the piping and an outlet configured to permit flow of the fire suppressant fluid through the conduit from the inlet to the outlet,
• an electrically actuatable valve controlling flow of the fire suppressant fluid only in the double interlock pre-action sprinkler head, the electrically actuatable valve directly attached to the inlet of the conduit, the electrically actuatable valve configured to prevent the fire suppressant fluid in the piping from entering the conduit through the inlet, the electrically actuatable valve actuatable in response to a signal from a fire detector to permit the fire suppressant fluid in the piping to flow through the inlet into the conduit,
• a heat-sensitive valve directly attached to the outlet of the conduit of the double interlock pre-action sprinkler head, the heat-sensitive valve actuatable from a closed state in which the fire suppressant fluid in the conduit is prevented from exiting the conduit through the outlet to an open state in which the fire suppressant fluid in the conduit is permitted to exit the conduit through the outlet, the heat-sensitive valve actuating from the closed state to the open state when ambient temperature at the heat-sensitive valve is at or above a predefined temperature, and
• a state detector configured to monitor whether the heat-sensitive valve is in the closed state or the open state,
• wherein the fire detector and the state detector are in electronic communication with a controller, the fire detector and the state detector are configured to provide electronic signals to the controller and the controller is configured to:
• open the electrically actuatable valve when the fire detector signals existence of a fire and the state detector signals that the heat-sensitive valve is in the open state;
• and,
• keep the electrically actuatable valve closed when the fire detector is not signaling existence of a fire but the state detector signals that the heat-sensitive valve is in the open state.