A Survey on Effective Factors in Accidents of Geisour-Gonabad Water Supply Pipeline

In this paper main factors associated with the accidents of Geisour-Gonabad water supply pipeline are investigated including continuous and transient pressures, water hammer control devices, air-valves, environmental conditions, and pipe material quality. The pipeline system is modeled for steady state condition, using WaterGems software, to calibrate Hazen-Williams roughness coefficient. A transient flow is initiated and the pressure heads are measured and compared with the computational pressures from Hammer software. More numerical tests indicate satisfactory performance of the system in the presence of surge control devices. Air-valves have no significant effect on transient flow. Laboratory tests demonstrate that water is neither corrosive nor scale forming. Finally, ensuring the satisfactory performance of protective devices, corrosion and low quality of pipe material are suggested as the predominant causes in the accidents of this pipeline. Estimating the maximum allowable length of corrosion and failure stresses based on ASME-B31-2009 code and comparing with the measured values confirm this assumption.