It has long been known that pressure transients (water hammer) can have an adverse effect on the integrity of pipelines and becomes evident when water hammer causes a pipeline to fail.
It is now believed that up to 60% of mains failures and bursts are pressure transient event related.
Transient events can be caused by numerous operations in the network, from pumps start up and shut down, closing of reflux valves, improper valve and hydrant operations, large consumer demand, process plant operations, fire service operations, water tanker filling, all can cause damaging effects to your assets and greatly reducing their life expectancy.
Identifying these events and their cause allows corrections to operations to be made, which will in turn reduce mains failures, burst and extend the life of the assets.
However, most pressure transients occur without ever being noticed because the event duration can be as short as 100 Hz and can cause incremental damage every time a transient occurs. Unfortunately shockwaves of this nature can significantly weaken the pipeline to the point of failure so measuring the operating pressure in a pipeline is an important aspect of understanding the system hydraulics.
Due to the speed of the shockwave conventional pressure data loggers are not adequate to detect and quantify pressure transients but we use a specially designed Transient Data logger which has been designed and tested to meet the stringent requirements to record pipeline transients.
The GCR Triton IT Transient data logger range of data loggers use a new data logging architecture that allows the user to monitor pressure input in terms of average values based on typical 15 minute logging rate plus minimum/ maximum values based on fast sample rates down to 1 second for the main recordings. In addition the Triton IT Transient logger can also detect and log pressure surge data up to 1000 readings per second without interfering with the main recordings. During threshold logging, the logger checks the pressure signal against the threshold settings 10 times per second and once triggered starts logging data at one of the configured log rate of 10Hz, 100Hz or 1KHz.If external power is connected the logger can sample pressure at 1KHz continuously, detect and record data at 10Hz, 100Hz or 1KHz before during and after the surge event.
At Detection Services we have been commissioned to monitor many sites both potable water and rising sewers with great success and the graphs below show actual field results from the logger.