Evaluation of minimum residual pressure as design criterion for South African water distribution systems

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dc.contributor.authorJacobs H.E.
dc.contributor.authorStrijdom J.L.
dc.date.accessioned2011-05-15T15:58:09Z
dc.date.available2011-05-15T15:58:09Z
dc.date.issued2009
dc.description.abstractThe South African civil engineering fraternity has grown to accept 24 m as the design criterion for minimum residual pressure in water distribution systems. However, the theoretical peak demand in many systems has increased beyond the point where minimum residual pressure exceeds 24 m - at least according to hydraulic models. Additions of customers to existing supply systems have led to increased peak fows with time, often without infrastructure upgrades to internal reticulation. Increased fows imply reduced pressures. This is not necessarily a concern: peak fow conditions rarely occur in a supply system and also, customer complaints often act as a frst sign of 'low pressures'. No complaints imply 'no low pressures'. The researchers analysed hydraulic models for 14 different towns in 5 municipal areas of South Africa, including 2 large metros, to identify the minimum residual pressures currently expected. The results include almost 55 000 model nodes and show that about 20% of the nodes in the distribution systems analysed have pressures of below 24 m, while pressures of below 14 m are not uncommon. Whether this relatively common occurrence of low pressures under modelled peak demand is found in practice is not known at this stage. A new guideline for minimum residual pressure based on previous criteria and results from this study is presented, noting that a physical lower limit of about 10 m water pressure is specifed in home appliance specifcations.
dc.description.versionArticle
dc.identifier.citationWater SA
dc.identifier.citation35
dc.identifier.citation2
dc.identifier.issn3784738
dc.identifier.urihttp://hdl.handle.net/10019.1/10803
dc.subjectCustomer complaints
dc.subjectDesign criterion
dc.subjectDesign standard
dc.subjectDistribution systems
dc.subjectHome appliances
dc.subjectLow pressures
dc.subjectLower limits
dc.subjectPeak demand
dc.subjectPeak fow
dc.subjectReduced pressure
dc.subjectResidual pressure
dc.subjectResidual pressures
dc.subjectSouth Africa
dc.subjectSupply system
dc.subjectWater pressures
dc.subjectCivil engineering
dc.subjectDesign
dc.subjectDomestic appliances
dc.subjectHydraulic models
dc.subjectHydraulic structures
dc.subjectLocal area networks
dc.subjectWater supply
dc.subjectWater distribution systems
dc.subjectcivil engineering
dc.subjectdesign
dc.subjectdistribution system
dc.subjecthydrological modeling
dc.subjectinfrastructure
dc.subjectpeak flow
dc.subjectpressure
dc.subjectwater supply
dc.subjectAfrica
dc.subjectSouth Africa
dc.subjectSouthern Africa
dc.subjectSub-Saharan Africa
dc.titleEvaluation of minimum residual pressure as design criterion for South African water distribution systems
dc.typeArticle
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