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INTRODUCTION TO URBAN WATER DISTRIBUTION - CHAPTER 4

Thiết kế vận chuyển nước và hệ thống phân phối bao gồm hai phần: thủy lực và kỹ thuật. Các thông số chính được xem xét trong thiết kế thủy lực đã được thảo luận trong chương trước. Ngoài dòng chảy đầy đủ, áp lực và vận tốc, một hệ thống được thiết kế tốt nên thực hiện đầy đủ các yêu cầu bổ sung sau đây: - giảm thiểu chi phí hoạt động trong điều kiện cung cấp thường xuyên, cung cấp hợp lý trong những tình huống bất thường (không điện / máy bơm, ống nổ, các sự. | CHAPTER 4 The Design of Water Transport and Distribution Systems The design of water transport and distribution systems consists of two parts hydraulic and engineering. The main parameters considered in hydraulic design have been discussed in previous chapters. Apart from sufficient flows pressures and velocities a well-designed system should fulfil the following additional requirements - minimised operational costs in regular supply conditions - reasonable supply during irregular situations power pump failure pipe burst fire events system maintenance rehabilitation or reconstruction and - flexibility with respect to future extensions. Engineering design criteria Keeping the hydraulic parameters within an acceptable range cannot by itself fulfil these requirements. Equally important are so-called engineering non-hydraulic design criteria such as - the selection of durable pipe materials joints fittings and other appurtenances - setting a network of valves whereby parts of the network can quickly be isolated and - providing easy access to the vital parts of the system etc. Respecting both the hydraulic and engineering design criteria guarantees satisfactory operation of the system throughout the entire design period. 4.1 THE PLANNING PHASE Choosing to commission a water distribution system means a huge investment with far-reaching implications for the development of the area that will be covered by the network. To avoid major mistakes starting with a good plan is a meaningful preparatory step before the detailed design considerations take place. The planning phase has to answer the following questions Pieterse 1991 1 Is the project feasible 2 What is the best global approach 2006 Taylor Francis Group London UK The Design of Water Transport and Distribution Systems 123 3 What are the estimated costs 4 What is the required timescale for execution Looking for appropriate answers in this case is often a complex assignment in which experts of different profiles are .