Abstract: A thermally-resistant composite fabric sheet for use as single or outer layer of protective garments, comprises inside and outside fabric layers (B,A) joined together by an array of connection lines (12,22,32) arranged so that the inside layer forms bubble-like pockets (16) when the outside layer (A) is caused to shrink by the external application of intense heat. The array of connection lines (12,22,32) is constituted by a plurality of isolated single connection lines (22) and/or by a plurality of isolated groups of connection lines (12,32), for example forming a series of Y or V shapes. The connection lines are arranged at different angles and are spaced apart from one another to leave gaps (42) where the two layers (A,B) are not connected to one another. These gaps (42) unite a continuous expanse (40) of the two unconnected layers that surrounds each isolated connection line (22) or group of connection lines (12,32).