What sort of pipe diameter do you really need?
They're all handled by a small continuous extrusion mill, which is adjustable for pipe diameter.
The range of pipe diameters for each pipe system does vary.
The wrench is adjusted to different pipe diameters by rotating the key ring (silver in the picture).
With a decreasing pipe diameter, the drag reduction is increased.
The standard pipe diameter was typically 2 inches.
One benefit to this drainage technique is the reduction in required pipe diameter to drain a given roof surface area, up to half the size.
The deeper the well, the smaller the pipe inner diameter must be, given the available power constraints.
The length of the reduction is usually equal to the average of the larger and smaller pipe diameters.
At distances greater than 25 pipe diameters the error asymptotes to zero.