ESDU 84013 provides a simplified graphical method for predicting maximum pressure changes in liquid filled pipework systems that may be treated as one-line systems. The method applies to pressures induced by partial or total valve closure@ covering all common valve types@ or pump trips. Data are also given for the estimation of the size of air vessel@ situated just downstream of a pump@ to protect against excessive upsurge and downsurge pressure changes following pump trip. A Basic program listing is included to analyse transients in one-line systems and does not use the simplifying assumptions necessary for the graphical data. Practical worked examples@ illustrating the use of the methods@ are included and guidance is given on the data required for a full fluid transients analysis going beyond the scope of ESDU 84013.