On 26 August 2010 the Department of Environment, Food and Rural Affairs (Defra) and the Welsh Assembly Government launched a consultation on draft regulations to facilitate the transfer of private sewers and private lateral drains to water and sewerage companies in England and Wales. This process has now been concluded and the implementation date for the transfer is 1 October 2011.
This in itself is a major change in UK sewer policy but alongside this legislation the new Sewers for Adoption 7 document has been drafted. One of the most significant elements of this document is that a revised minimum build technical standard will be applied to all new sewer applications throughout England & Wales. With the original planned implementation date of October 2011 having been missed, it is likely to come into effect in April 2012. This standard requires gravity sewer pipe systems to have a minimum water-jetting resistance of 4000psi which most plastic and structured wall pipes cannot achieve.
Because some plastic sewer pipes had been damaged during routine maintenance, 4000psi water jetting resistance was made a requirement by Thames & Anglian Water in 1995 and by Southern Water in 1997 and the Ultra Fortis structured wall pipe system was developed specifically by Radius Systems Ltd to address this, with Burdens as principal distributor.
>> Plastic drainage for adoptable sewers PDF <<
Fully approved to BSEN 13476 and with 4000psi jetting resistance independently witnessed and certified by BSi, the Fortis system comes with a manufacturer’s lifetime jetting guarantee.
On product launch in 2005, Southern Water – who have always welcomed innovation – quickly became aware of the significant advantages and greater long-term asset life that the system offers and began to build all their first-time sewer schemes and maintenance replacement projects using it. Similarly, when Wessex Water in 2010 had to overcome difficult engineering conditions as well as a restrictive time-frame in constructing the transfer pipeline for their wastewater treatment works at Doulting, innovation was seen as the key. Wessex therefore opted to use the Fortis system to overcome the anticipated difficulties and actually completed the scheme ahead of schedule.
Apart from its 4000psi jetting resistance, the system also addresses other concerns raised by water companies regarding plastic and structured wall pipe systems: for example, the ‘thinness’ of pipe walls is overcome with an increase in wall thickness of Fortis pipe over similar systems of between 48% and 73% depending on pipe diameter. Another great concern for water companies is the proliferation of tree root ingress into sewer pipelines. Joints are typically the weakest points of pipeline installations and it is recognised that lip-seal type joints actually enable roots to penetrate. Fortis is manufactured in 3m lengths, reducing the number of joints in a system compared with traditional pipe materials and uses a compression ring seal that forms an efficient barrier against tree roots.
As well as the benefits offered, the system is very user-friendly for contractors and installers: the pipe can be cut using a simple handsaw and, with a 3m long 300mm pipe weighing just 21kg, there is no need for mechanical handling on site.
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