This series is used for a garage or conditioned space where flood protection is required but air ventilation is not desired, for situations where a sealed crawlspace is being utilized in a floodplain, flood protection is still required and the Insulated Flood Vent series is the perfect fit for those applications. Ventilation: The flood door contains a 2″ styrofoam core that has an R-value of 8.34. There is also a felt weather stripping that lines the entire vent frame helping to keep the enclosure as insulated as possible. Flood Protection: The vent door is latched closed until it comes in contact with flood water. Entering flood water lifts the patented internal floats which unlatch and allow the door to rotate open. This allows the flood water to automatically enter and exit through the frame opening, relieving the pressure from the foundation walls. Certified flood debris clearance is demonstrated with a 3″ diameter opening when the flood door is activated. Covers 200 sq ft (square feet).