Roof Hatch – Ladder Hatch, factory fabricated, Dur-Red Products curb and curb frame and lid shall be 14 gauge galvanized steel or aluminum, fully welded and ground smooth for absolute weather tightness; completely assembled with “heavy-duty” 3/16″ galvanized pivot hinges; lid to have a fiberglass insulation, protected by a 22 gauge lid liner; inside, outside handles with padlocking provisions; “heavy-duty” air-flow pressure intensifier control; automatic hold-open and operating arms with red vinyl handle grip; and bulb-neoprene seal