Specifications include, but are not limited to: B. Fabrication Requirements: 1. Fittings a. Flange Nozzles: 1. Rated at 50 psig, minimum, with flange outer diameter and drilling per ANSI 16.5. 2. Back face of the flanges shall be spot-faced, flat, and parallel to the flange face of sufficient diameter to accept an SAE metal washer under the bolt head or nut. 3. Flange nozzles shall be conically gusseted with strength requirements of 1500 ft-lb of bending and 2000 ft-lb of toque. Flanged nozzles 4 inches and smaller shall be gusseted. 4. Standard orientation will have bolt holes straddling principal centerline of vessel and a radial line on tank top. 5. 40-50 durometer 1/8-inch thick full-face gaskets shall be used. Gaskets shall be suitable for chemical stored. b. Couplings, Nipples, Pipe Stubs: Shall be of filament wound or contact molded construction. Press molded fittings are not acceptable. c. Drain line shall include true-union ball valve. Drain fitting shall be designed and located such that the entire volume of the tank can be drained. d. Vent: Provide size as per the Tank Schedule, with 180 fittings, with FRP insect screen.