Specifications include, but are not limited to: A. Roof Hatches: Metal roof-hatch units with lids and insulated double-walled curbs, welded or mechanically fastened and sealed corner joints, continuous lid-to-curb counterflashing and weathertight perimeter gasketing, straight sides, and integrally formed deck-mounting flange at perimeter bottom. 1. Manufacturers: Subject to compliance with requirements, provide products by one of the following: a. Babcock-Davis. b. Bilco. c. Milcor. d. Williams Brothers. B. Type: Single-leaf lid. C. Loads: Minimum 40-lbf/sq. ft. external live load and 20-lbf/sq. ft. internal uplift load. D. Hatch Material: Zinc-coated (galvanized) steel sheet. 1. Thickness: Manufacturer's standard thickness for hatch size indicated. 2. Finish: Baked enamel or powder coat.