Galvanized Steel Pipe Specs

• Galvanized pipe can be used for many applications. Chris Leschinsky/Photodisc/Getty Images

  Galvanized steel pipe is used in a wide range of industries and applications, from electrical conduit to water pipe. Due to the variance in application, galvanized pipe is classified according to a few specifications including the outside diameter, inside diameter or wall thickness, and even the overall shape of the pipe.

Outside Diameter

• The most common starting point for many pipe applications is the outside diameter. When coupled with the wall thickness, the outside diameter determines the volume inside the pipe and the flow rate of fluid running through the pipe when used in plumbing situations. When used in electrical applications, the diameter determines the amount of wire or cable the pipe can hold. Diameters generally range from less than one-half-inch up to 36-inches wide for the largest applications.

Schedule

• In engineering terms, the wall thickness specification is measured in increments known as schedule under the nominal pipe size. These sizes include schedule 5, 10, 30, 40, 80, 120 and 160. The most common schedules are 5, 10 and 30 with schedule 10 being used for many plumbing applications. Though the schedule is standardized, the actual wall thickness does vary within schedule according to the outside diameter. This variance in thickness maintains strength across the schedule.

Shape

• Another pipe specification is determined by the shape of the material. While round pipe is often the least expensive and most commonly used, different shapes exist for other applications. Square, oval, hexagon and rectangular pipe is available though these shapes are more often referred to as tubing and not pipe. These non-round shapes also preclude the pipe from using threaded fasteners.