Engineering & Specs. Capacity Charts Permastore U.S. Gallons Permastore Metric Climate Tanks™ U.S. Gallons Diameter Nominal (DN millimeters) to Nominal Pipe Size (NPS inches) Climate Tanks™ Shop Drawings Firewater 3D Firewater Perspective Silo/Standpipe Conical Roof & Railing Rectangular Tank Trough Deck Roof Climate Tank™ Renderings Standpipe Silo Sides & Roof Sides & No Roof Conical Roof Conical Overhung Roof Flat Roof Elevated Tank