Sadler, Burn, Whittle
Joints & Joining # 2001 Munich
Root intrusion into sewer pipelines is a major concern, especially in areas with a combination of dry climate and vigorous vegetation growth. For elastomeric pipe joints to resist root intrusion, some national standards specify a minimum interfacial pressure that must be maintained between the elastomeric ring and the spigot. The appropriate interfacial pressure has been under discussion for some time and different values have been stated in different standards. This matter has been the subject of considerable controversy, as decisions on the interfacial pressure used will affect both the performance and the ease of insertion of an elastomeric ring joint. If interfacial pressure is low, root intrusion may occur, resulting in infiltration or exfiltration through the pipe joints. High interfacial pressure can make installation difficult and increase the risk of ring dislodgment. A study has been undertaken to assess the effects of interfacial pressure and spigot deformation upon root intrusion into PVC pipelines. This follows previous work investigating the role of socket geometry and controlled flaws. Root intrusion occurred in many joints with deformation and average interfacial pressures of 0.04, 0.10, 0.11 and 0.20 MPa. However, no intrusion occurred in joints with interfacial pressures of 0.37 MPa, even with socket deflection, despite these joints having small contact widths of less that 0.5 mm where the interfacial pressure exceeded 0.3 MPa. In light of these findings, the current Australian Standards requirement for an interfacial pressure of 0.4 MPa to be exceeded over a minimum contact width of 4 mm is considered more than adequate to prevent root intrusion. The interfacial pressure requirement is considered conservative, but satisfactory. The contact width requirement is also considered conservative, but necessary to account for the possibility of damaged pipes or rings.
Related papers
Author(s) : Alan Whittle, Jim Campbell
The coal seam gas industry in Australia is currently undergoing a major expansion with over 50,000 km or 30,000 mile of PE100 pipes to be installed in diameters ranging from DN110 to DN710. The pipes are being used to carry produced water, gas and treated water. The considerable quantity of pipe to be installed in...
Author(s) : Nigel Jones, George Macovaz, Alan Whittle, and Mark Heathcote
Key Words : PVC, Green Building Until recently the Australian green building rating tool effectively created a disincentive to use PVC pipe. The PVC industry in general and the PVC pipe industry in particular worked with the Green Building Council of Australia (GBCA) and associated stakeholders to establish an...
Author(s) : Alan Whittle, Nigel Jones and Mark Heathcote
PVC has been used successfully for sewer and sanitary drainage pipes in Australia for over 40 years. It is the predominant material for these applications. The reason for this success is the superior, all round performance of PVC piping systems compared to the various alternatives. Equally important has been the...
Author(s) : Whittle, Pesudovs
The process of extracting scrap plastics pipes from the demolition and construction waste stream in a major city is described together with a quantification of the proportion of the most common plastics pipe materials in the waste. The condition of the pipes and the methods used to turn them into a re-usable form is...
Author(s) : Whittle, Tennakoon
Ipswich Water commenced reviewing the service lives of different pipe materials in its gravity sewer system. Unlike other pipe materials, PVC sewers did not have failure histories, or deterioration revealed in CCTV inspections, even after 25 years of service. Therefore establishing a realistic predicted life was not...
Author(s) : Whittle, Teo
PVC-U and PVC-M pipes may be used in applications where they are subjected to cyclic pressures generated by the operation of pumps and valves. It is therefore important that the pipe material’s response to cyclic loading is quantified and that pipelines are designed and operated within the material’s established...
Author(s) : Tjandraatmadia, Burn
To increase understanding of chemical jointing in pipes, the strength of solvent cement joints in acrylonitrile-butadiene-styrene (ABS) and poly(vinyl chloride) (PVC) pipes was investigated, using mechanical tests and morphology studies. The strength of solvent cement increases with curing time, and it was found that...
Author(s) : Whittle,Burford, Hoffmann
A series of modified PVC pipes, with different concentrations of chlorinated polyethylene, were manufactured under carefully controlled processing conditions. The strength and toughness of each pipe was measured by a variety of methods including uniaxial tensile strength, notched C-ring, essential work of fracture,...
Author(s) : Davis, Burn, Whittle
The C-ring test method is widely used by the water industry to determine the fracture toughness of poly(vinyl chloride) (PVC) pipes. The test currently forms a draft ISO standard (ISO/DIS 11673.2) and an interim Australian/New Zealand Standard (AS/NZS 1462.19(Int)) for fracture toughness assessment. Whilst results...
Author(s) : Stahmner, Whittle
A number of PVC pressure pipes were exhumed from a large rural water supply scheme constructed in the early 1970s. The pipes had been extruded by three manufacturers in both elastomeric seal and solvent cement joints. The pipes were subjected to a range of mechanical tests in order to assess whether there had been any...
Author(s) : Burn, Davis, DeSilva, Marksjo, Tucker, Geehman
To allow long-term strategies to be implemented for the replacement or refurbishment of water pipelines, a planning model called the Pipeline Asset and Risk Management System (PARMS) has been developed. This model, although based upon life cycle costing methodologies has been designed to incorporate whole of life...
Author(s) : Lu, Burn, Whittle
For rubber ring joints to resist plant root penetration, it has been reported and promulgated into Australian Standards that a sufficiently high contact pressure between the rubber and the pipe must be maintained. The evaluation of the appropriate interfacial pressure to be used has been under discussion for some time...
Author(s) : Lu, Burn
One of the characteristic behaviours of plastics (or viscoelastics) materials is the creep phenomenon, which is defined as the continuing deformation under a constant load with time. Although research on creep of plastics pipes has been widely carried out in other plastics, little work has been reported for creep in...
Author(s) : Whittle, Burford)
Modified PVC pipes are being introduced for water reticulation where their tough, predictable behaviour offers advantages in both performance and material utilisation. CPE is one of the modifiers used, either alone or in combination with other additives. The effects of changes in processing conditions on both the...
Author(s) : Burn, Richards
Fracture toughness tests have been used with uPVC pipe for more than a decade. Standard methods of testing are described in British and ASTM Standards and in an I S 0 draft. Analysis of the British methods associated with the introduction of a fracture toughness test into joint Ausmlia/New Zealand Standards for...
Author(s) : Burn
When plastics pipes are installed in water reticulation or pumped sewer systems they are normally subjected to installation damage, the level of which can vary enormously depending on the care taken during installation. Cyclic pressure testing of uPVC pipes with various levels of simulated installation...
Author(s) : Samt, Whittle, Hoffman, Burford
Author(s) : Ambrose, Rahilly, DeSilva, Burn
Author(s) : Whittle, Resenberger, Tan
Members of the Association
