Gate valves, special reinforced threaded ends, Buna-n, sizing: 1-1/2-inch. Schedule 80 pipes are thicker, heavier designed to handle more PSI than Schedule 40. In the United States, Schedule refers to the thickness of the pipe wall and, therefore, how much pressure it will hold. In most aquaculture applications, Schedule 40 is used. The main reason to use Schedule 80 is if it is mandatory in your area for specific applications but it can also be used on cold water loops to help insulate. Schedule 80 is rated at no less than 200 psi at 73 degrees F (up to 2 inches) and is usually Gray (similar to the Schedule 40 pipe used for electrical conduit). The outside diameter (O.D.) is the same as Schedule 120 and 40, but the inside diameter (I.D.) is smaller. Backed by over 40 years of both product and process development experience, Spears have become one of the leading manufacturers of thermoplastic valves, fittings, and piping system components. Spears broad product line offers a complete selection of 1/8-inch through 12-inch injection molded fittings and fabricated fittings through 48-inch, many specialty products, and a full complement of manual and mechanically actuated thermoplastic valves in a variety of types, sizes, and configurations.