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The introduction of asset management period six, known as AMP6 by industry regulator Ofwat has seen water company costs measured on a total expenditure basis for the first time, which requires the proper consideration of the long term performance of assets in addition to capital cost efficiencies.

The five year period of AMP6 between April 2015 and March 2020 aims to increase the efficiency of asset management without increasing costs for consumers.


Under previous asset management periods, water companies have tendered contracts to construction firms to update some of the company’s assets and to keep existing infrastructure properly maintained for the five-year duration of the AMP. Ofwat, however, was concerned that under these AMPs water companies may have been using capital expenditure (capex) to build assets, such as water treatment works, to make a business more valuable for its shareholders rather than on reducing operational expenditure (opex) to deliver better value to customers.

Read more »

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main_image_v2This blog focuses on deflection of flexible (e.g. plastic) sewer pipelines and aims to inform the reader so that appropriate decisions can be made when designing, specifying, buying, installing and operating a sewer pipeline.


It is vitally important that users understand the differences between flexible pipes such as plastic and rigid pipes such as concrete and to appreciate how these materials perform in terms of structural integrity and hydraulic efficiency.

CPSA has produced a number of publications covering this subject, all of which can be downloaded free of charge on our web site.

What do you know


Posted by & filed under Sustainable Drainage.

The latest issue of Pipelines, CPSAs eNewsletter focuses on sustainable drainage systems (SuDS). It contains an excellent case study at where a residential development in Leicestershire used a combination of soft landscaped SuDS features and precast concrete SuDS components. Also featured is information on latest SuDS technical guidance and standards in England and Wales plus other useful references and case studies from the CPSA.

For more information on the use of concrete for sustainable urban drainage systems visit our website. If you would like to receive regular updates in the concrete drainage industry you can register to receive our free monthly eBulletins and quarterly eNewsletters!

Posted by & filed under Newsletters.

Welcome to the Winter 2015/16 issue of Pipelines, your eNewsletter from the Concrete Pipeline Systems Association.

It’s a sad fact that the need for effective surface water management, flood prevention and resilience tends to get insufficient attention until we are confronted with the problem. But we do have the tools to make a real difference. In this issue you will find lots of valuable information and access to material to bring you right up to date with sustainable drainage systems (SuDS) Best Practice. This is a seriously important step in getting to grips with the situation. I hope you find these insights useful.

Stuart Crisp, Director, CPSA

SuDS solution combining Concrete Proprietary Drainage Products with Soft Landscaped Drainage Features. has published an excellent case study demonstrating the intelligent combination of vegetated components with proprietary precast concrete SuDS systems to achieve a technically valid sustainable drainage system and commercially viable housing development for Jelson Homes at London Road, Markfield, Leicestershire LE67 9UR.

CIRIA’s Updated SuDS Manual (C753)

The SuDS Manual first published by CIRIA in 2007 (C697), is the onestop-shop for delivering SuDS and it is this guidance that has been significantly revised. The updated SuDS Manual incorporates the very latest research, industry practice and guidance and is available to download free of charge.

Recommended non-statutory standards for sustainable drainage in Wales

The Welsh Government has published it’s recommended Standards for Sustainable Drainage Systems (SuDS) in Wales. These standards have been developed over the course of two years, during which time extensive engagement with stakeholders was maintained for public consultation purposes.

The next steps will be to work with stakeholders to determine how best take forward the SuDS agenda. This includes whether or not to commence with the Flood & Water management Act 2010, which states that new features of SuDS must not only comply with but help in the development of national standards.

CPSA Case Studies

FPMcCann precast concrete pipes and tunnel segments are key to alleviate flooding in North West London Read More >

Severn Trent approves Stanton Bonna Elliptical Pipes Read More >

FPMcCann precast concrete rainwater attenuation tanks help manage storm water runoff from new housing development Read More >

CPM precast concrete provides Perfect drainage solution on the first Government supported self-build supersite in St Helens Read More >

FPMcCann precast concrete culverts enable innovative surface water drainage solution at Wakefield and District Housing development.
Read More >

CPM Bespoke Solution Saves Time at Gainsborough Project
Read More >

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CPSA Information on Precast SuDS

The use of SuDS should be an integral part of any development’s surface water management strategy.

CPSA members offer a wide variety of proprietary SuDS components and systems suitable for use within a sustainable drainage system. These are listed in the table indicating their functions within the Management Train. For more information on Precast SuDS products, consult the table here or view our references online.


CPSA currently offers industry professionals the choice of four accredited CPD presentations. These presentations have also received the approval of The Chartered Institution of Water and Environmental Management (CIWEM) and are recognised as CIWEM Accredited Short Courses. All the presentations can be offered as a free seminar at your local office or at a suitable location. CPD certificates are available to all attendees.

Posted by & filed under Uncategorized.

Stuart Crisp, Business Development Director of the Concrete Pipelines System Association explains the advantages to be gained from working with precast concrete pipeline manufacturers to deliver the optimum drainage solution.

The more challenging a pipeline project the more important it is that contractor, distributor, manufacturer and client work effectively together to deliver the optimum drainage solution. This was the case with construction of the Chelmsford Effluent Pipeline. Here the project team had to overcome a lack of site storage, a high water table and, most challenging of all, a delivery date which was abruptly brought forward by six months and yet were still able to deliver the project on schedule.

This £9million project for Essex and Suffolk Water, part of Northumbrian Water, was constructed to almost double the capacity of the existing dual sewerage outfall from 828l/s to 1524l/s with the installation of a third pipeline.

The 1.4m diameter gravity pipeline was installed by civil engineering contractor Roadbridge along an 11km route from the Chelmsford sewerage treatment works to an existing outfall location on the River Blackwater Estuary. Buried between 3m and 5m below the surface, the pipeline connects to existing concrete pipelines both upstream and downstream. This made precast concrete the obvious material choice for the new pipeline.

Roadbridge worked with consultant RPS Group to develop the scheme’s detailed design. One of the challenges the team had to overcome with the pipeline’s route through the low-lying Essex countryside was dealing with a very high water table. To enable the pipeline to be installed in the low-lying ground, Roadbridge constructed a series of de-watering boxes 200m ahead of the pipe laying team. These temporarily lowered groundwater levels to keep the trench free of water during construction, while the self-weight of the concrete pipes helped guard against flotation during and after installation.

It was, in fact, because of the high water table and the likelihood of winter flooding that the project’s delivery date was brought forward by six months to ensure its completion by November.

Suddenly bringing forward the project’s delivery date by six months placed an increased onus on precast concrete pipe manufacturer and CPSA member Stanton Bonna Concrete to deliver. To meet the revised deadline Stanton Bonna introduced double shift working to significantly increase pipe production. Alongside increasing output the manufacturer also arranged storage for 4000m of pipe to enable the pipe supplier Keyline to meet a just-in-time delivery schedule. Keyline’s Gareth Twohey said the company did “a fantastic job” in working with Keyline to ensure it met the revised completion date.

Delivery of the precast concrete pipes was also a challenge. Access to the pipeline was predominantly from narrow, single lane country roads with limited space for delivery vehicles and storage. To ensure the operation ran smoothly, Keyline took the unusual step of pre-booking the haulage three months in advance.

This project demonstrates the benefits that can be gained from working closely with precast concrete pipe manufacturers and the advantages of pipes with high inertia (due to high self-weight) to counteract the risk of flotation in high groundwater. For the Chelmsford effluent pipeline, the efforts of the supply chain and precast concrete pipe manufacturer were essential in helping deliver this challenging project on schedule.

Posted by & filed under Design.

Wikipedia defines inertia as the resistance of any physical object to any change in its state of motion (this includes changes to its speed, direction or state of rest). It is the tendency of objects to keep moving in a straight line at constant velocity. P08 Pipe Stabilitycropped copy

So, why is inertia important for buried sewerage structures? Without (lots of) inertia, pipes can become more easily dislodged from their intended position during and after installation.

  1. Most sewer pipes are jointed using a push-fit design where an elastomeric seal is compressed between the interlocking ends of two pipes being joined together. If the receiving pipe has low inertia and insufficient resistance to the jointing force applied from the pipe being laid, additional restraint may be required to hold the receiving pipe steady and to maintain the correct position while the pipe being laid is pushed home. This additional effort during installation can increase construction time and means that operatives are working in the trench for longer periods and can be subject to higher safety risk exposure.
  2. Backfilling and compaction. Pipe embedment should be placed and compacted evenly around the pipe to the correct specification. Unbalanced forces acting on each side of the pipe due to uneven backfilling and compaction can lead to a greater tendency for the displacement of pipes with low inertia.
  3. After installation, if the surrounding ground is subject to a high water table or if the ground is saturated, for example during a flood, pipes of low inertia are at greater risk of flotation. Take a look at the video below demonstrating a stunning failure of a corrugated steel culvert in Maine State, USA due to flotation during a flood. In known areas of flood risk or high groundwater levels, resistance to flotation can be designed into the installation for low inertia pipes, at extra cost and requiring a more complex, longer installation time.

Why does concrete outperform other pipeline materials?

Concrete is the Heavyweight Champion of the drainage world. The intrinsic self-weight of concrete provides high inertia to pipeline systems and a natural resistance to being moved out of position during jointing, backfilling, compaction and against flotation.

High inertia concrete pipes are the only sensible choice for a strong, stable, robust and durable wastewater pipeline system.

Posted by & filed under Case Studies, Health & Safety.

Have you ever wondered the comparative flammability of different drainage pipes?


Polypropylene pipe, reinforced concrete pipe and high density polyethylene pipe. We look which drainage pipe will be crowned champion with this unedited test conducted in October, 2015!

Dry hay is ignited in three 18/18 in pipes and allowed to burn safely. What happens next? Which pipe will survive?!

For more information on concrete pipes please visit the CPSA website in the link to the left.

Posted by & filed under Design.

In their 2014 Spring newsletter, the American Concrete Pipe Association (ACPA) decided there was the need to publish an abrupt and insightful article rejecting claims that the direct design method provided by the American Association of State Highway and Transportation Officials (AASHTO) should be used to design reinforced concrete pipes. This position may have been initiated by competitors from the HDPE pipe industry making claims that concrete pipes, designed with the indirect design method (also provided by AASHTO) would not sufficiently withstand the loads for which they had been designed. ACPA boldly stated within the article that there was no basis for these claims and that they were being used as a ploy to obscure the long-term proven history of the indirect design method with scare tactics with no technical justification.

The indirect design method is a proof of manufacturing method that has spanned two centuries and is simple to use. It uses a bedding factor which relates the governing moment applied to installed pipe with the moment on a concrete pipe that is tested using a three edge bearing test. The pipes are given strength classes according to the test loads they sustain. The pipes can then be specified for application using the strength class and bedding factors. Since the steel requirements of the pipe produced are dependent on the proof-of-manufacturing test, not directly designed by an engineer, this is called the indirect design method.

The direct design method is based on design coefficients utilising uniform pressure distributions along the sides, tops and bottoms of the pipe; not unlike the pressure distributions that were used for the bedding factors when the indirect method was initially developed. These pressure distributions were considered a rough approximation of the pressures induced on a pipe in its installed condition. The pressure distributions and resulting design coefficients could then be used to develop equations for the moments, shears and thrusts in the concrete pipe wall. Using these values, an engineer can then directly design the steel reinforcing required for the concrete pipe wall. Hence, the term ”direct design”.

The article then went on to inform that HDPE pipes are extremely installation sensitive, no such proof-of-performance test exists and that an extensive design method must be followed to analyse the capability of thermoplastic pipes; along with the post installation inspection program that must follow. It then also implored engineers to base design on sound engineering principles rather than be taken in by the fear tactics of an alternative industry trying to increase market share.

Strong words! It is satisfying to know that the UK use a similar method of design to the indirect design described above. Would you not agree that confidence is gained from using a pipe that has been routinely proven by test? The proven performance throughout the history of indirect design certainly gives assurance regarding design life. So much so that, as up to around 80% of the design strength is inherent within a concrete pipe itself, it can be used in many cases to allow users to choose from a range of bedding solutions requiring less granular embedment thus reducing installation cost, construction time and environmental impact. The use of sound engineering principles using the indirect design method certainly should be recommended.

Written by: Gareth Hughes, Chairman CPSA Technical Committee and Technical Manager at CPSA member company FPMcCann.

Posted by & filed under Maintenance.

JettingCodePracticeOne of the most common forms of maintenance carried out on wastewater pipelines is high pressure water jetting; a process used to ensure that pipes run free of blockages and to remove accumulated material that would otherwise compromise the hydraulic performance of the system.

In the UK, sewer jetting is a widely used technique for clearing blocked pipelines with comparatively little routine preventive maintenance on sewer networks. As such, it is generally considered an emergency operation and there is a considerable burden on the operative to clear the blockage quickly.

Some pipe materials such as concrete and clay have a very high tolerance to the jetting pressures often required to remove blockages and some water companies already specify 4000psi minimum jetting resilience for sewers, so it would make sense for this to be consistently applied nationwide.

Some may argue that pipelines can be cleared at lower jetting pressures, but the risk remains that higher pressures may sometimes be used to clear stubborn blockages and in these situations some pipes of certain materials, such as thin walled plastic, are vulnerable and may become damaged.

When specifying a pipe with a high jetting resilience such as concrete, an indirect benefit of superior robustness, strength and durability can be achieved. Click here to download the Jetting Factsheet

Posted by & filed under eNewsletters & eBlasts.


Welcome to the Autumn 2015 issue of Pipelines

In this issue you will find lots of information on sustainable drainage systems (SuDS) including a compelling case study, blogs, reference sources, a Factsheet and a free CPD seminar. Surface water management is entering a new phase and CPSA members are well placed to offer advice and product solutions.

I hope you find this material useful.

Stuart Crisp, Director, CPSA


SuDS solution combining Concrete Proprietary Drainage Products with Soft Landscaped Drainage Features. has published an excellent case study demonstrating the intelligent combination of vegetated components with proprietary precast concrete SuDS systems to achieve a technically valid sustainable drainage system.

Click here to read more


We are a Susdrain Supporter

CPSA joined the impressive cross-sector group of organisations in 2014 dedicated to supporting the initiative, further demonstrating growing industry support for widespread delivery of Sustainable Drainage Systems (SuDS).

Over the next two years, it is anticipated that there will be a significant increase and improvement in the delivery of SuDS, with positive change driven by new guidance and the potential implementation of National Standards for Sustainable Drainage. susdrain will help support improvements in SuDS delivery through a range of initiatives including new resources, summaries of the latest guidance, case studies and a series of topical SuDS events.

CPSA is one of 29 organisations including Defra, the Environment Agency and other key industry players involved in the project from September 2014.

Since its launch in 2012, Susdrain has provided a valuable range of resources for those involved in delivering SuDS. Susdrain will continue to support drainage and highways engineers, planners, urban designers, landscape architects, land or housing developers, suppliers, flood risk managers, biodiversity / environment managers and the general public to increase knowledge and confidence in the delivery of SuDS.


CPSA Sustainable Drainage Solutions

The use of SuDS drainage systems best management practices should be an integral part of any development’s surface water management strategy. This should provide a basis for replicating the response of a catchment and its surfaces by mimicking, to some extent, the behaviour of surface water on the developed site as if it had remained undeveloped.

CPSA members offer a wide variety of proprietary SuDS components and systems suitable for use within a sustainable drainage system, many of which are listed in the download.