ARIavCAD ensures proper air valve sizing and installation for smooth water flow

In an irrigation project in Oldonyiro town in Isiolo county, Kenya, executed by the National Irrigation Authority through a local contractor, water is pumped through an OD315 uPVC rising main pipeline from the Ewaso Ng’iro River to a reservoir tank. The water then flows from the reservoir to irrigation distribution systems downstream. Just four A.R.I. D-040 air valves had been installed along the >9 km-long pipeline – a model smaller than required, and less than half the number of valves needed for such a distance.

During test pumping, the pipeline experienced various bursts. The water was never successfully pumped above 10 bars of pressure, the level required to pump it to the reservoir tank. No air valve sizing and location analysis had ever been conducted, and the pipeline did not have drainage valves installed, making it impossible to drain the pipe to remove debris during test pumping.

Air valve sizing and location analysis was carried out using ARIavCAD sizing and location software. Following this analysis, D-46 air valves, properly sized and with the required air flow capacity, were installed along the pipeline to minimize pressure transients, control air, and optimize flow. Air vent pipes were installed on the air valve chambers, and washouts were installed at all the low points, to enable flushing of debris from the pipeline.

ARIavCAD Sizing and location report
Data collected from the field was input into the ARIavCAD and analysis was carried out. The ARIavCAD graphical representation below shows the locations and types of air valves required.

Technical spec: A finely-tuned balance

Following installation of the new A.R.I. D-46 air valves in accordance with the ARIavCAD analysis, the air locks and accumulated debris that had prevented water flow were eliminated, and the upsurges and down surges that had been causing pipe bursts were mitigated. As a result, water is now successfully pumped to the reservoir tank.