Assessment of Pipe Failure Causes (Case Study on Chiro Town Water Supply Distribution System), Ethiopia
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Date
2021-09
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Addis Ababa University
Abstract
Intermittent water distribution is the key problem of many water authorities in developing countries including Ethiopia. Hence, this research was conducted to carry out a risk assessment of water supply pipe failure (burst) in the water supply system of Chiro town which is located in the eastern Oromia Region of Ethiopia. To investigate the cause of pipe burst in the town water supply distribution network, physical, pipe installation condition investigations of the distribution system and water GEMS modeling were utilized. Chiro town water supply distribution system was constructed in 2013 to 2015. More pipes were laid from 2014 to 2015 especially uPVC pipe and HDPE, but more pipe bursts were observed in uPVC pipe and HDPE pipe.
According to pipe failure (burst) history recorded in the town water supply distribution system, more types of pipe burst were found in plastic pipe (uPVC pipe and HDPE) than the other types of pipe (DCI and GI pipes). The water supply distribution piping is mainly of plastic pipes (89.17%) and 10.83 % other types. According to Chiro town’s water distribution system, the investigation of the factors causing pipe failure in the system was based on considering three factors (pipe condition assessment) such as physical factors (types of pipe materials, pipe diameter, pipe installation years), environmental factors or pipe installation conditions (pipe cover, pipe bedding and backfill practiced conditions) and hydraulic parameters (internal water pressure, transient pressure and also velocity).
As per the research results, the main causes of pipe burst in the water supply system were the type of pipe materials and its PN, water pressure, poor pipe installation practices, absence of selected material pipe bedding specially at rocky area and also absence of sufficient pipe cover and back fill for plastic pipe or uPVC and HDPE pipes.
In general, frequent pipe burst in the system leads to water losses and this contributes to interruptions (intermittent) of water supply in the town. Based on pipe condition/situation assessment and the relation between the parameters which contributes to pipe failure, identify which parameter/s are more related to the cases of pipe failure than the others and develop equation based on their relationship of the parameters with the probability of pipe failures. This is significant to rehabilitate /replacement/repair and improve the reliability of town water distribution system and providing more attention to pipe burst reduction strategies which are vital for remedial measures.
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Keywords
Pipe condition assessment, pipe break/burst, water GEMS modeling, Chiro town