ABSTRACT
This chapter considers friction loss in closed pipe systems. Friction losses occur with every foot of pipe length, and this must be included in head loss calculations. The longer the pipe, the more head loss. For determining head loss, find the proper discharge and line it up with the pipe diameter. For field use, as an alternate to calculating the Hazen-Williams formula, an alignment chart has become popular, and can be used with reasonable accuracy. It may yield an answer with one or more of its dimensions unknown. Minor Head Loss is caused by turbulence created at bends, valves, fittings, and changes in pipe diameter. Inspecting the nomograph, note the difference in equivalent pipe length between a fully open gate valve, and a 3/4 closed gate valve. In pumping operations, it is common practice to control flow rate by partially closing a valve on the pump discharge, thereby increasing the minor head loss, and restricting the flow.
