Scientific analysis and providing a way to improve the reliability of high-pressure urban gas networks for sustainable and safe gas supply by suppliers is essential. A reasonable forecast for the achievable flow for each subscriber at the time of failure is the critical network hydraulic reliability in quantitative analysis and is not easy in loop networks. In this article, based on hydraulic indicators and the principles of engineering economics, the degree of reliability and availability of the city gas network has been analyzed. The proposed method relies on the data and findings of the hydraulic analysis and hydraulic regime of node flow in the network and the reliability in different situations with the utilization coefficient of the pressure drop, based on actual flow is analyzed, and provide a solution in determining the cost of the gas supplier company. The results show that the hydraulic reliability of the network has a high impact on the stability of the gas network and for improve of it, the gas companies have to pay attention to design and implementation costs as well as repair and operation costs in network service time.
