The main objective of this publication is to analyse the performance of pressurised irrigation systems operating on-demand (also under other conditions) and to provide revised criteria for the design of such irrigation networks. For this purpose, new approaches and a computer tool (COPAM) have been developed. Calculation examples have been included to demonstrate the procedures and facilitate the understanding and practical use of formulae. This publication should be of particular interest to irrigation district managers, consultants, irrigation engineers and companies, university professors, students of irrigation engineering and planners. Includes diskette.