The results of water hammer
Many papers have been written about the results of water hammer damage to pipelines and pumping equipment and mostly concentrate on extreme damages caused – such as catastrophic pipe breaks and total equipment failure. With modern tendencies of reducing water project costs to enable affordability, wall thicknesses are kept to a minimum, and also with ageing pipelines long term damages are starting to appear in the form of cracks, seal/gasket leakages and other non-catastrophic failures which are not always obvious to maintenance staff, as pipelines are mostly buried. Such damages result in leakage and contaminant intrusion, and their resultant economic, environmental and public health repercussions. This is particularly true in the case of wastewater systems.
Engineers worldwide still have a concern about the reliability of air valves, and often consider that they can cause more damage than what they solve. Some engineers even go to the extent of designing out the use of air valves on Wastewater pipelines due to the traditional poor experience with these valves. The advancement made in some air valve designs is such that very reliable and inexpensive solutions are available which increases the lifespan and integrity of pipelines by reducing water hammer events, and the steady deterioration of the integrity of pipelines.
A Paper written by Naftali Zloczower of A.R.I Flow Control Accessories discusses this topic in great depth, and how the increased usage of air valves can reduce these damages to a minimum. This paper is available for download here.