Abstract: A fire resistant flexible seal for sealing a breach between movable architectural barriers. The flexible seal is comprised of a plurlaity of layers of fire resistant materials. In a preferred embodiment, a first non-porous sheet is affixed to each side of the breach and forms an open loop within the gap. The size of the loop may be varied to accommodate the amount of movement anticipated by the architect. A blanket of ceramic insulating material is nested within the loop formed by the non-porous sheet and a second blanket is mounted in an open loop across the breach, thereby defining an enclosed air space between the ceramic insulating blankets. A second non-porous sheet is nested within the upper ceramic blanket and serves to enclose the ceramic blankets within a moisture resistant envelope. In alternate applications in which it is desired to achieve the capability to withstand high pressure, an additional sheet of high strength heat resistant material can be added to the seal.