After outlining some of the problems associated with the design of fluid flow networks a brief survey is made of the methods whereby such systems have been simulated. The use of analogue techniques for this purpose is discussed and an attempt has been made to compare the various methods proposed. As a result of this study certain improvements were considered to be worth seeking, and a new type of simulator is described based on the exponential family of pipe resistance laws. A novel feature is the independent control of simulated length and diameter.