WET News

right bedding for pipes is easier as a number of factors need considered. Stuart Crisp explains. challenge: Putting the to bed JUNE 2015 WET NEWS 19 THE CONCEPT • Most of the rigid pipe's design strength is inherent in the pipe itself • Concrete pipes, installed with cover depths of between 2m and 4m, can be used with Class B bedding under a main road • Class B uses much less bedding because it requires only the lower half of the pipe to be surrounded • Class B bedding can be used for pipelines installed at depths of up to 8m • Class B bedding is a common solution for concrete pipelines right bedding for pipes is easier as a number of factors need considered. Stuart Crisp explains. challenge: Putting the to bed NEED TO KNOW • A common bedding solution for concrete pipeline installations is Class B • Flexible pipes need to derive a proportion of their structural strength from the embedment either side of the pipeline • The more bedding used for an installation, the larger the volume of excavated material that will be displaced • Flexible pipe installations depend on a high quality installation where the surrounding embedment takes most of the pipeline's designed loading THE VERDICT Opting for rigid pipe, drainage contractors will have scope to select the most economical bedding solution based on material cost, installation time and environmental impact. installation will depend on the material from which the drainage pipe has been fabricated, the strength characteristics and structural classification of the pipe itself, traffic loading and the depth at which the pipe is installed. BS9295 provides examples of common pipe materials, their strength and their structural classification. Concrete, clay and reinforced concrete, have a structural classification of 'rigid', ductile iron and thick-walled steel pipes are termed 'semi- rigid', while thermoplastics, glass reinforced plastic and thin- walled steel are all classed 'flexible'. Bedding is particularly important for flexible pipes, such as sewer pipes manufactured from HDPE. This is because flexible pipes need to derive a significant proportion of their structural strength from the embedment either side of the pipeline to prevent them deflecting under load, usually by flattening on top and spreading laterally - a condition termed ovalisation. As a consequence of their lack of inherent strength flexible pipe installations depend heavily on a high quality installation where the surrounding embedment takes the majority of the pipeline's designed loading. The problem with using a large quantity of imported granular embedment is that it will o‰en require considerable quantities of aggregate to be extracted from a quarry, gravel pit or by marine-dredging. It is then graded before finally being transported to site, which can add considerably to a scheme's cost. Also, the carbon embodied in the embedment can be substantial. And, the more bedding used for an installation, generally the larger the volume of excavated material that will be displaced from the trench, where disposal of this material by transport to landfill is likely and where both the cost of the installation and the carbon embedded in it will increase further. For installers of flexible drainage pipes, this means the option of using a cheaper, more e n v i r o n m e n t a l l y - f r i e n d l y alternative to Class S bedding is less likely. by 26 June Book by 31 July Full rate (+VAT=£426) £395 (+VAT=£474) £435 (+VAT=£522) (+VAT=£546) £495 (+VAT=£594) £535 (+VAT=£642) by 26 June Book by 31 July Full rate (+VAT=£714) £635 (+VAT=£762) £675 (+VAT=£810) (+VAT=£786) £765 (+VAT=£918) £805 (+VAT=£966) Charity Partner Organised by Supported by The Water Industry Energy & Carbon Management Conference is the only event to specifi cally address the challenges of reducing energy usage and carbon emissions and increasing renewable energy investment and innovation in the uk water sector. Taking place on Day 2 of Sustainable Water 2015, the 4 th annual event brings together senior representatives from water companies, contractors, consultants and other key stakeholders in the water sector to examine innovative approaches to: • Maximising energy e' ciency and recovery opportunities in AMP6 • Investment in e' cient infrastructure to deliver cost-e" ective and sustainable projects • The CRC Energy E' ciency scheme and how the water sector has fared so far • Gaining operational e" ectiveness through meeting mandatory audits and going beyond compliance • Multiple demand-side programmes and their cost/operational benefi ts and challenges • Creating self-su' cient treatment works through energy recovery and onsite renewables Book online at www.WWT-energy.net Maxine Mayhew Commercial Director Northumbrian Water Matthew Pluke Energy Manager Anglian Water Chris Toop General Manager - Energy Scottish Water Dr. Bruce Horton Senior Consultant UKWIR Dan Green Head of Sustainability and Innovation Wessex Water Mike Denbigh Technical Lead and Government Liaison CRC EŽ ciency Scheme - Environment Agency EXPERT SPEAKERS INCLUDE Professor John Bridgeman Director - Research & Knowledge Transfer, Birmingham University, Vice Chair, ICE Water Expert Panel CHAIR Follow us @WWTlive using #suswater Supported by SusWater-WIECM-brochurevs2.indd 3 18/05/2015 17:16 Industrial Penstocks Limited Total Flow Control Quality Assured Products Quality Assured Service Unit 1 & 2 Washington Ind Est, Washington Street, Netherton, West Midlands DY2 9PH t: 01384 458411 f: 01384 246952 sales@industrialvalve.co.uk Industrial Valves Limited Total Valve Packages Penstocks Installation and Site Support Actuated Valves Pipeline Products PolyLine ® - the simple solution for water treatment sera ProDos UK Ltd. 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