Design Safety

This chapter addresses important safety issues associated with pipeline and pumping systems. Quite often hydraulic systems are designed without safety measures, resulting in system failure and financial losses. The chapter opens with a summary of the equations used. It goes on to describe causes of hydraulic system failures and the equations needed to evaluate system tolerance to various adverse conditions. Charts and tables for calculating the risk level and designing safety measures are included, together with examples of safe design of hydraulic systems and risk assessments for various components of typical hydraulic systems. This chapter addresses important safety issues associated with pipeline and pumping systems. Quite often hydraulic systems are designed without safety measures, resulting in system failure and financial losses. Sudden change of flow or velocity in a pipe due to valve closure, valve opening, pipe breakage, pump turn-on or turn-off can result in excessive change in pressure which can cause a pipe to burst or collapse. Excessive change in pressure will also cause pipe fatigue which can lead to its eventual failure. The resulting force would be infinite. Fortunately, such an instantaneous change is almost impossible because a mechanical valve requires a certain amount of time to complete a closure operation. In addition, neither the pipe walls nor the water column involved are perfectly rigid under high pressure. The soil is said to be homogeneous if there are identical elastic properties at every point of the mass in identical directions.