Abstract: An improved, soft-seated fire-safe ball valve is disclosed. The ball valve includes a body having a central passageway, a ball member positioned in the passageway, and a pair of radially inwardly extending shoulders in the passageway disposed circumferentially thereof on opposite sides of the ball member. The ball member includes a fluid flow opening therethrough and is mounted for selective rotation between valve open and closed positions to control fluid flow through the valve. An improved seat assembly is provided comprising a rigid reinforcing ring, an elastic seat ring supported by the reinforcing ring and configured for fluid sealing engagement to the ball member, and a deformable, heat resistant secondary seat ring interposed between the elastic seat ring and an associated one of the pair of shoulders. Also, a weir ring may be advantageously received in the seat ring. Upon fire damage to the elastic seat ring, the secondary seat ring engages the ball member to seal the valve.