Methods of Making Flow Tests and Their Value to Water Works Engineers

About twenty years ago, the National Board of Fire Underwriters organized a corps of engineers to survey and report on the adequacy of the fire fighting facilities of the larger American cities; since that time other fire insurance organizations have undertaken similar work for the smaller towns and villages and have extended its scope to cover individual plants or risks. It was early emphasized that pressure alone meant nothing with respect to the delivering capacity of a water system, and various attempts were made to devise a practical method of measuring fire flow available. Calculations could be made in some cases, but these became much involved in a well gridironed system, and were misleading in many instances. In some of the early tests of systems, a number of engines were connected to hydrants and operated simultaneously; this was expensive and inconvenient, and left the city poorly protected during that time. Other methods were used, such as the flow from a number of hydrants through short hose lines or the discharge of individual hydrants through a special venturi nozzle. Eventually a system of testing by groups of hydrants was evolved, and after