Specifications include, but are not limited to: A. Acceptable manufacturers. 1. Wayne-Dalton Corp. - Thermospan Door, Model 200 2. ThermoMar 530 3. Midland CU-175 4. Clopay Model 3730 5. Substitution only by written approval of Mn/DOT D8 Physical Plant Manager at 320-214-6314. B. Doors 1. Door sections shall be sandwich construction consisting of exterior and interior steel skins pressure bonded to expanded polystyrene or polyurethane core, steel skins shall be roll formed commercial quality hot dipped galvanized G-60. Minimum skin thickness - exterior 26 gauge and interior 27 gauge. Exterior and interior skins shall have a complete thermal break separated with silicone or vinyl extrusion. 2. All sections shall have double wide end stiles to accommodate long stem rollers. End stiles shall be totally closed 16 gauge minimum separated from exterior skin with vinyl thermal break. Top section shall have rubber or vinyl seal (door greater than 16'-0" shall be minimum 3" wide) and bottom shall have an extruded aluminum retainer with vinyl U astragel, sides of opening shall have vinyl jamb seal that are easily replaceable.