# 1982 York
A study has been carried out which has sought to establish the influence of processing conditions on the properties of medium and high density polyethylene. Residual stress and fracture toughness measurements have been carried out on hdpe pipe, from which predications of the influence of diameterlwall thickness on the stress rupture performance have been made.
Author(s) : Dr. Dane Chang, Dr. David Marshall, Chris Cox 2014 Chicago
Plastic pipe applications often require polymers to have adequate abrasion resistance during usage. Although typical polyethylene resins have reasonably good resistance to abrasion and can be broadly used with a variety of chemicals, there are some demanding applications that require a resin with enhanced abrasion and...
Author(s) : Marshall, Brogden, Shepher 1998 Gothenburg
Many early brittle failures in PVC water and sewerage pipelines, where repeated surge events are thought likely to induce embrittlement, were attributed to fatigue. The concerns of pipeline engineers led to the adoption of the British Standard Code of Practice CP 312 (ref. 1) by the UK water industry, which gives...
Author(s) : Marshall, Morley, Pearson 1998 Gothenburg
The Water Industry in England and Wales has responsibility for an approximate length of 300,000km of water main, ~nuchof which was laid over 70 years ago using cast iron.Subsequently, asbestos cement, PVCu and cement lined ductile iron have been used. The old iron pipe systems that were installed in many of the...
Author(s) : Marshall, Hepburn, Netherwood 1995 Edinburgh
The adoption of polyethylene as a pipe material by both the gas and water indusmes has undoubtedly led to several sigruf~cant economic and operational advantages. The development of narrow trenching techniques and insertion refurbishment methods only became viable once a complete fusion jointed polyethylene system was...
Author(s) : Marshall, Ingham, Brogden 1995 Edinburgh
When clients purchase plastics pressure pipes, they have frequently made that decision because they know that plastics do not corrode and they assume that if they do not exceed the pressure rating then a long lifetime should be assured. (Low cost has also been known to be a factor). It is thus of concern for the...
Author(s) : Marshall, Birch, Morley 1995 Edinburgh
Many UK Water Companies are now using PE pipe systems because it 1s believed that use of an all-welded pipe will minimise the number of mechanical fittings employed and therefore will reduce potential sources of leakage. With pipes such as ductile iron and PVCu, which are joined in short lengths, it is often...
Author(s) : Lowe, Marshall 1988 Bath
A Rotating Pipe Drum Test has been developed to assess the abrasion performance of plastics pipes to an extpnt where most test variables are understood. The procedure involves the rotation of relatively short pipe lcngths containing slurry on a conventional bail mlll. In the rest, the pipe surface repeatedly passes...
Author(s) : Marshall, Birch-Kisbenyi, Youd 1988 Bath
A complete analysis of the Charpy impact system has been made to relate measurements of impact toughness to the geometry of samples. Using data obtained on pipe grade polyethylenes, Gc values at 20°C and 3°C have been found to correlate wel! with measurements of resistance to fast fracture in pressurised pipe...
Author(s) : Young, Thomas, Marshall 1988 Bath
Within the Water Industry in England and Wales, there is an estimated length of 295,000 km of water main, much of which was laid in unlined cast iron prior to 1940. Subsequently, asbestos cement, UPVC and cement lined cast/ductile iron has been uscd. It is kn-that a substantial number of...
Author(s) : Marshall, Birch 1985 York
It is proposed that present Specifications for PE Pressure pipes are essentially undemanding and tests do not simulate service conditions. Perfect pipes are assessed rather than pipes which have sustained handling and installation ‘damage’.Flaws and defects have caused many problems with other thermoplastics pipes...
