PerformanceRequirements for Elastomeric Sealing Pipe Joints –
WaterSupply and Sewerage
ReportNo WSAA 138
Poorperformance of pipe joints in water and sewerage pipelines means that waterauthorities unnecessarily spend millions of dollars annually in treatment andmaintenance work, such as clearing root intrusions and blockages. Some of thispoor performance occurs because of the lack of adequate joint performancerequirements in Australian pipe standards. The current performance requirementsgiven in standards for elastomeric sealing rings used in pipe joints have anumber of inconsistencies across the different pipe material types. They areeither currently unnecessarily restrictive through the use of prescriptiveproperty requirements or inadequate in that they define minimal or noperformance requirements. These problems increase costs, reduce freedom to takeadvantage of developments in technology and adversely affect competitiveness inexport markets.
Inthis report, previous and current research on the performance and evaluation ofelastomeric joints is reviewed and the inconsistencies across the differentpipe material types are discussed. To establish a background to the developmentof pipe and pipe joint systems, with a focus on elastomer joint design, asurvey was conducted among a range of rubber manufacturers, pipe manufacturersand water authorities. Based on the information from both the survey and aliterature review, the ability of elastomeric joints to resist root intrusionhas been highlighted as the main performance requirement necessary for seweragepipelines. Experimental assessment of root intrusion using sewerage pipematerials such as vitrified clay, plastic and fibre-reinforced cement has beenundertaken using various types of common joints, with different levels ofinterface pressure. A finite element modelling technique is described forevaluating whether the interface pressure between rubber ring and spigot andsocket, under shear load conditions, is adequate to stop sewer infiltration andexfiltration. Finally, uniform performance requirements for elastomeric pipejoints for pressure and non-pressure pipeline system components are proposed.
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