US Patent 9376803 Flood vent trigger systems

A flood vent includes a door pivotable within a frame between a closed position and an open position. A fluid trigger that is triggerable by a fluid to allow the door to pivot from the closed position to the open position includes a retainer and a fluid modifiable material. The fluid modifiable material is positioned between the door and the retainer thereby obstructing the door from pivoting from the closed position to the open position until the fluid modifiable material is modified by contact with the fluid.