Factors Controlling the Lifetimes of Polyethylene Pipes in the Slit Mode Failure Regime [PE]

Author(s) : J.Bowman

Polyethylene (PE) resins are known to be sensitive to both sunlight and high ambient temperatures, such that excessive exposure can degrade the material. The inclusion of stabiliser packages into the polymer controls this potential for damage from outdoor aging. Reported in this paper are results on the stability and...

Author(s) : Christodoulou, Wilson, Hunter, Bowman

Polyethylene (PE) based and metallic pipe systems have been assessed for their ability to stop petrol migrating through the pipe wall, fitting or joint and into water contained within the pipe. A quantitative test was devised that is capable of distinguishing between the different pipe systems. Plain PE pipe...

Author(s) : Lever, Palermo, Wright, Oliphant

The piping industry has a need for a well-founded methodology to predict lifetime of pipeline components subject to stress concentration. Another useful tool would be a method to assess the impact of manufacturing processes on the slow crack growth (SCG) properties of a resin that can be used for process control in a...

Author(s) : Wood, Richards, Street, Muckle, Bowman

For the movement of fuel gas and water, plastics pipes are dominant in many markets, and this success has been based on single material solid wall pipes. There are now an expanding number of multi-layered plastics pipes, and described here for the first time is the performance of the second-generation of skinned pipe...

Author(s) : Hunter, Christodoulou, Greaves, Bowman, Bott

The development of a pipe system designed to transport potable water through contaminated ‘brown-field land’ is described. The system is based around a multi-layer, aluminium reinforced PE pipe, and includes a full range of specially designed mechanical fittings to provide the end user with a total system solution. We...

Author(s) : Stokes, Potter, Metcalfe, Bowman, Graham

The response of three different forms of polyvinyl chloride (PVC) pipe has been explored when the pipes had attached to them ferrule straps. Pipes were subjected to fluctuating internal pressure (fatigue) loading at 20°C, and the lifetimes, location of any failures and the types of failures recorded. Tests were made...

Author(s) : Wright, Burley

Advanced Engineering Solutions Limited (AES) and Colin Burley Associates have jointly developed and patented a Silane cross-linked polyethylene liner for the internal lining of pipelines, known as the (SPEX ) liner. For a number of years Medium Density Polyethylene (MDPE) pipe has been extensively used as a liner to...

Author(s) : Bowman

The many technologies associated with the production, installation and uses of plastics pipes systems increase in their sophistication and diversity This paper selects and reviews changes that have and are taking place with polyvinyl chloride (PVC) and polyethylene (PE) pressure pipe systems designed for canying...

Author(s) : Cartwright, Troughton, Hinchcliff, Bowman, Jenkins

For the butt fusion joining of PE80 polyethylene pipes on site, long heat soak and cooling times predominate in the United Kingdom and other countries. The literature is reviewed to propose that these heat soak and cooling times can be significantly reduced via the use of machines with verifiable, reduced short...

Author(s) : Bowman,Medhurst, Portas

For two sample shapes different procedures have been examined as methods to quickly and quantitatively assess the strength of electrofusion joints. It is shown that the peel test, specified in BS7336, can be added to in order to obtain a quantitative measure of joint strength either using the % ductility on the...

Author(s) : Bowman

The influence of time and temperature on the long term strength of a multilayer pressure pipe has been investigated. The pipe consists of five layers, one of which is an aluminium foil while the other four layers are polyethylene based and form the significant ( > 8 5 % ) part of the pipe wall. In respect of strength...

Author(s) : Aboutorabi, Bowman

A rwte for the marufaoture of large diameter polyethylene pipe fittings, based on a unique combination of mtommld- ing and irradiation, is pmposed. The method requires a low investment in twling but can give rise to pressure rated, mulded fittings, capable of being fusion jointed to polyethylene pipe. This...

Author(s) : Bowman

Elevated teqerature fatigue of MDPE pipe system showed socket and electrofusion fittings had similar fatigue lifetimes, while butt jointed pipes failed at repmducibly lower lifetimes. Extrapolatims to 2O'C preserved the raking in joint performance, although combined creep ad fatigre tests showed pure fatigue...

Author(s) : Parmar, Bowman

The performance of aligned and controlled misaligned butt welds in 63 and 90mm polyethylene pipe systems was determined under fatigue loading conditions designed to induce brittle failure. The results showed a significant reduction in fatigue lifetime for butt welds having fractional misalignments greater than 10% of...

Author(s) : Barker, Bowman, Bevis

The influence of the incorporation of injection moulded fittings and the presence of mirror plate butt welded joints on the performance of polyethylene pipe systems has been assessed. Systems have been tested at 79.5OC under, predominantly, internal fatigue pressure loading. Both fittings and butt welded joints have...