Transienter i VA-ledningsnät – en statusbedömning för VA-sverige
Unintentional or planned operations of valves and pumps create pressure waves, called transients, which travel through pipe systems with the risk of, among other things, breakage and fatigue. Knowledge about transients in pipes and associated effects are not new. The problems with transients in Sweden were elucidated in a report published in the 1980s, where several municipalities reported examples of pipe damage created by transients. With the aim of performing a follow up on the conclusions from this report, an overall survey was conducted to assess if problems and handling of transients have changed. The survey was carried out in the spring of 2021 and sent to seven of the larger water- and wastewater authorities in Sweden, where an assessment of the status on transient management was requested. For reasons of comparison, the survey contained similar questions as the survey from the 1980s. Results show that the problem with transients still exists for the authorities. Examples include injury among the operation staff, when hit by a valve detached from the piping system. Another example involves a flooded booster pumping station for fresh water. In total, all of the authorities provided examples of pipe bursts originating from transient events, indicating room for improvement. However, the authorities are familiar with the problem and stand positive to future cooperation in research and development projects within the field of transients.