Posted by & filed under Construction, Design, Standards & Specifications.

All newly-laid drainage pipes, including manholes, should be tested for leak-tightness prior to backfilling.

There are two basic tests; the air test and the water test. An air test involves using inflated stoppers at both ends of a section of the pipeline under test. Pressure is then introduced into the section of pipeline and after a stabilisation period the pressure is checked. In the event of a single or continued air test failure, recourse to a water test is allowed and the result of the water test alone shall be decisive.

A water test involves creating a head of water in the pipeline which is examined for tell-tales signs of leakage. Following a period of settlement and acclimatisation, the level of water in the header tank is monitored for a specified period and the loss of water measured and checked. It is not unknown for a pipeline that has failed an air test to pass a water test.

For more information about leak-tightness testing refer to BS EN 1610:1998 – Construction and testing of drains and sewers.

We have a video on how to air test concrete pipelines on our YouTube channel. Please click here to view the video.

Posted by & filed under Pipes & Manholes, Standards & Specifications.

Off-site manufactured precast concrete base manhole systems offer some big advantages compared to traditional in-situ solutions. Clients, contractors and specifiers have, until now, been unable to take full advantage of the benefits of using a precast solution for circular manholes because the British Standard did not include a specification for the precast base unit.

That has now changed. The latest changes, BS5911-3:2010+A1:2014 Specification for unreinforced and reinforced concrete manholes and soakaways now covers the specification of precast base units. The Standard has additional significance because it is referenced in Part H of the Building Regulations, which defines the rules with which drainage systems must legally comply.

The benfit of using a BS-compliant, Kitemarked circular precast manhole solution from CPSA members is that users can be sure that the product will comply with all necessary technical requirements.

Another change is that two new rectangular manholes (in this case square) are included with preferred nominal sizes 1000mm x 1000mm and 1250mm x 1250mm. Two publications BS EN 752: 2008 Drain and Sewer Systems Outside Buildings and Sewers for Adoption 7th edition, provide guidance on minimum nominal sizes for circular and rectangular manholes.

Regardless of the shape, if a manhole includes a ladder or step irons then users need to refer to the HSE confined spaces regulations. These recommend a minimum 900mm clearance between the steps and the back of the shaft. Generally ladders and steps project more than 100mm. Users will need to use square manholes with preferred nominal size at least 1250mm x 1250mm or a circular manhole with a 1200mm diameter or greater.

The size of the manhole is also critical if the sewer is to be adopted by water and sewerage companies in England and Wales. Within Sewers for Adoption 1050mm diameter and 1000mm x 1000mm square manholes are too small to comply with the nominal minimum internal dimensions.

The revised Standard also makes a distinction between the structural behaviour of circular and rectangular manholes. Concrete is very strong when used in compression. As a result, a circular manhole is the ideal solution for constructing a vertical buried structure because the uniform, circular shape ensures that the forces acting on the manhole create distributed compressive stresses around the circular structure. This enables a circular manhole to be installed to a greater depth than for other shapes of chamber with similar material strength classes.

For square or rectangular manholes, ground pressure can be an issue because tensile stresses are created on the manhole’s flat faces and at the corners. The Standard provides a mathematical calculation method to help users determine the maximum permissible installation depth of rectangular manholes for a defined strength class to determine when, or if, it might be possible to use a square or rectangular manhole.  By contrast, using a circular manhole in lieu of a square equivalent is generally a straight forward process.

These changes to the Standard should enable users to take full advantage of circular, off-site manufactured manhole solutions. This will allow installation time to be cut by up to 50% and to reduce installed costs by 15-30%. The factory manufactured solution also has significant environmental benefits because it uses less concrete than equivalent units constructed on-site, which means there is up to a 43% saving in embodied carbon.

The CPSA’s publication Technical Bulletin 4 gives further information on the changes to the Standard.

Posted by & filed under SuDS, Sustainability.

On 12 September 2014, Defra and DCLG launched a joint consultation document, which set out a possible approach for implementing sustainable drainage systems and mechanisms for ensuring their long term maintenance. There are some important differences between the proposed new approach and the previous direction that the industry was heading.

The proposed new approach may avoid delays to the planning process, compared with the SuDS Approval Body (SAB) approach, but SuDS and drainage expertise is still required. This is not generally found in the town/district/borough councils and therefore may have to be sub-contracted. The anticipated general consensus among responses to the consultation is that the proposed approach is the path of least resistance and therefore could see SuDS delivered more quickly. There is however concern for the quality that will be delivered.

Sam Ibbott, Deputy Public Affairs Director of the Environmental Industries Commission stated “The government’s new proposal to deliver SuDS through the planning system is the path of least resistance – it will see SuDS delivered quickly, but not automatically to a high standard” This opinion was echoed by The British Water group “As a group, whilst we feel the proposed approach, if implemented in Spring 2015 will inevitably deliver a solution at least, it is not as far reaching and clear as the originally proposed SAB route.”

Furthermore, The Environmental Industries Commission as a whole stated “With these new proposals the Government has taken the path of least resistance. Overall, we do not feel that the new approach is ideal, but in the circumstance we believe it is workable. It is preferable to find a workable version of the current SuDS proposals by amending the planning system, than to start again and incur even further delays.”

Focus on maintenance is essential but with numerous scenarios, that the new proposal creates, in terms of asset ownership and operation, there will be less certainty in terms of responsibility and liability for maintenance. Gareth Twohey, National Sector Manager for utilities at Keyline raised some issues on this point “Who owns the new asset, and should therefore maintain it? The issue of adoption is crucial, but it’s purely down to how the local authority enforces it, and could leave the taxpayer with huge maintenance costs”

Also another major change with these new proposals is the minimum threshold for SuDS requirement of more than 10 dwellings (or “equivalent”). Many feel that this may lead to developers exploiting the potential loophole with partial development of plots in stages. British Water highlighted the loophole in their response to the consultation “This may well provide a loophole to be exploited by developers and it would be better if this requirement revert back to how it was originally intended, i.e. as a temporary measure during the early part of implementation so ultimately all developments needed to comply.”

The new proposal does not address cumulative effect of numerous smaller plots being developed in close proximity as highlighted by the DSSF response “We are not clear why there should be a special dispensation for developments of less than 10 properties. Clearly in any borough there could be several developments of up to 10 properties that could, taken together, have a greater volume of surface water run-off than a smaller number of larger developments. Furthermore there is no reference to the size of the properties or square area of the total development site.”

The withdrawal of Schedule 3 of the Flood & Water Management Act 2010 and the proposed changes will mean that SuDS will no longer be a legal requirement associated alongside the planning process but diluted down to a planning consideration; it will be down to each individual local authority to lay down their own requirements for SuDS.  This will lead to inconsistencies nationally between local authorities and their demands on developers, which could in turn lead to disputes based on precedent. Gareth Twohey, National Sector Manager for utilities at Keyline stated “By nature, local planning looks at local needs when it comes to new development, and not at the wider context. SuDS has to be holistic rather than site-specific to work properly, looking at crucial ramifications downstream of new installations. Moving the problem onto someone else’s patch could result in a nightmare scenario, when more joined-up thinking might have mitigated this risk”

The proposed changes also only relate to water quantity and flood risk mitigation.  They do not account for water quality and as such, apply to a narrower remit.  Some would argue that this is not true to the three fundamental SuDS principles of (i) water quantity, (ii) water quality and (iii) amenity and biodiversity.

In the British Water response to the consultation they state “There is a strong feeling that water quality is given much less of an emphasis with the new proposals and seems to have been framed almost entirely around flooding issues, probably as a result of the more recent and well publicised flooding problems (Somerset Levels etc.) and the needs to comply with WFD requirements seem to have been missed (accepting that the Water Quality standard No.12 is still currently included in the Draft National Standards).”

In summary the proposed changes in the consolation could see SuDS delivered more quickly which is something that all parties involved agree is a positive step forward. There are however various issues that will need to be addressed in order to produce successful sustainable drainage systems.

For more information on Sustainable Urban Drainage Systems follow the link or give us a call today!

Posted by & filed under Design, Health & Safety, Maintenance, Standards & Specifications.

On 28th September 2014 fire-fighters were called to a fire at a building site at Cargo Fleet Lane, Middlesbrough after reports that 20 large plastic sewerage pipes had deliberately been set alight. The blaze resulted in the streets surrounding the site having to be cordoned off after the area was blanketed in a cloud of noxious black smoke.

Similar incidents have been reported in America. One such example is where children playing in a 42” diameter storm culvert built a fire to keep warm; this then set light to the HDPE pipe which resulted in fire damage spreading for over 800’ along its length.

It is not just arson that pipe users need to be aware of, brush fires, vandalism, fuel spills and industrial accidents all have the potential to initiate fires in pipelines. As a result, designers, installers and asset owners should consider combustibility and the risk of fire when selecting pipe materials, gully tops and drain grates.

Plastic burns. If these pipelines had been constructed from a non-combustible material, such as precast concrete, it is unlikely that either of these fires would have occurred, simply because concrete does not burn.

Where a fire has occurred in a drainage pipeline a secondary consequence of a fire is the impact of the fire on the pipe itself. Fires in concrete pipes generally do not affect their structural strength, flow capacity or corrosion and abrasion resistance, whereas plastic pipes can melt and collapse.

All of which raises the question: is the use of drainage pipe materials other than concrete really worth the risk? Concrete has inherent strength and a proven service life of over 100 years … and it is non-combustible.

Posted by & filed under Training.

The construction CPD RoadSeminar Tour continues in October visiting Cambridge and Nottingham. The tour will visit Menzies Cambridge Hotel on 1st October and at the Novotel in Nottingham on 2nd October.

I will be presenting a seminar on ‘Surface water management using proprietary precast concrete suds systems’ at these locations. I see this as an important opportunity to provide leading edge, expert information relevant to our industry.

The subject matter itself is of particular interest at the moment especially since the release of Defra’s consultation document which I referred to in my last blog.

Whether you are involved with the construction of new or existing developments surface water management is something that you will be required to deal with. As such, this CPD will appeal to stakeholders with a particular interest in construction projects requiring surface water drainage.

The aim of the seminar is to provide an understanding of the legal framework driving changes in the design and construction of surface water management systems. I will outline the basic principles associated with sustainable drainage systems (SuDS) and their ownership, operation and maintenance. I will indentify proprietary precast concrete SuDS components and systems and their specific uses will be examined.

You can view the full programme and download your booking forms for both the Cambridge and Nottingham seminars online here .

If you can’t make these dates or locations then please refer to back to the CPSA website.  All of my presentations can be offered as a free seminar at your local office or at a suitable location. You can use the CPSA online booking form to book a CPD of your choice.

Posted by & filed under SuDS, Sustainability.

On 12th September a joint consultation document was launched by Defra and DCLG it can be viewed here. The consultation offers just six weeks to formulate responses with a deadline for returns by 24th October 2014.

The consultation sets out an alternative approach to that indicated in The Flood and Water management Act 2010 to deliver sustainable drainage systems that will be maintained for the lifetime of the development they serve.  This represents a modified approach to that seen previously and does not align entirely with the “final” draft National Standards for Sustainable Drainage published by Defra on 7th July 2014.

There appears to be a particular emphasis on changes to the current planning system to ensure that sustainable drainage is the system of choice for new development (there are exceptions and a size threshold, i.e. 10+ properties / 1,000+ sq metres floor area / 0.5Ha+ land area), that maintenance arrangements are put in place and that maintenance costs are ‘reasonable’.

The need for appropriate planned and costed maintenance fits precisely with the CPSA’s message regarding asset lifetime value and the importance of selecting proprietary SuDS components and systems using durable materials that offer a long, low maintenance service life.  Precast concrete provides a perfect answer with proven long asset life and authentic sustainability benefits

It will be interesting to see what feedback comes back to Defra / DCLG and what, if any of the proposed changes that will go through.

For more information on Sustainable Urban Drainage Systems follow the link or give us a call today!

Posted by & filed under SuDS, Sustainability.

In the past year extreme weather events have led to devastating flash floods and the occurrence of current global climate change has caused previously rare environmental issues in the UK.

As urban areas become increasingly developed, continued water management is a necessity. Although these urban drainage systems are complex networks it is possible for sustainable drainage to be achieved if a broad approach to the issue of drainage is adopted. Implementation of sustainable design techniques will ensure that a drainage system is a long-term viable option.

Surface water drainage systems which consider quantity, quality and amenity issues are referred to as Sustainable Urban Drainage Systems (SuDS). These drainage systems are more sustainable than traditional systems for many reasons.  Firstly they control the flow rate of surface run-off, reducing the impact of urbanisation. They also give consideration to the natural environment and community needs creating new wildlife habitats among the watercourses. SuDs also protect and / or enhance water quality and promote natural groundwater recharge.

The success of this sustainable approach to urban drainage is due to the system aspiring to deal with surface run-off at the point of which it occurs and to manage potential pollution at its source. The introduction of SuDS into an area means that future development can take place in areas where the capacity of the traditional drainage system is full.

SuDS are designed using the same principles as traditional drainage systems, but using different methods of application. Equal consideration must be given to the issues of quality, quantity and amenity resulting in a multi-disciplinary approach to drainage. It is essential that planners, designers, installers and operators of SuDS drainage systems take into account the importance of whole life maintenance and the use of suitable components that deliver authentic sustainable drainage performance and longevity.

In regards to how a sustainable drainage system is structured, this is underpinned by the Surface Water Management Train. The Management Train can be divided into the following processes: Collection, Treatment, Re-use, Infiltration, Attenuation and Conveyance. There are various vegetated and proprietary manufactured components that deal with these processes including precast concrete pipes and culverts. The management train recommends using a variety of techniques to deal with the issue of drainage. Drainage systems are part of a wider cycle of water and consideration of this is a must in terms of the development process.

If you would like more information on sustainable drainage please visit our main site.

Posted by & filed under eNewsletters & eBlasts.

Welcome to the Spring 2014 edition of Pipelines, your eNewsletter from CPSA.

An important step forward has taken place with the recent publication of of BS 5911-3 2010+A1 2014 “Concrete pipes and ancillary concrete products. Specification for unreinforced and reinforced concrete manholes and soakaways (complementary to BS EN 1917:2002) – incorporating the latest Amendment (AMD 1).
The latest changes include the specification of precast manhole base units, including provisions for benching arrangements along with some other significant changes. CPSA members’ innovative
circular precast manhole base systems are a water industry success story, providing a safer off-site construction solution combined with reduced installation costs, time savings, a consistently high quality build with durable, watertight joints and up to 43% lower embodied carbon compared with traditional manhole construction. The introduction of BS 5911-3 2010+A1 2014 along with the current Sewers for Adoption 7th Edition and the soon to be published revised Sewers for Scotland will complete the suit of industry specifications recognising the attributes of circular precast concrete manhole base systems. For more information, read Technical Bulletin 4 – BS 5911 Part 3:2014 – Important Changes

Have you seen our new
Blog Area? Please take a look and join the discussions. We also have news of the new Type 2 concrete pipe lifter, details of winners at the recent Water Industry Achievement Awards 2014, CPD News and details of the new “20 Reasons to use concrete” booklet.

Hopefully there’s something of interest for everyone!

Stuart Crisp, Director CPSA

New Type 2 concrete pipe lifter

CPSA is pleased to announce the introduction of a new Type 2 concrete pipe lifter, suitable for offloading and installing larger pipes DN1350 to DN2000. The Type 2 lifter is available from, Klepp Mek AS, a manufacturer working in collaboration with CPSA and Basal, a Norwegian supplier of concrete water and drainage products.

Klepp Mek’s contact details can be found on the main
concrete pipe lifter web page

Watch the video

Klepp Mek Type 2 concrete pipe lifter (DN1350 – DN2000)

Water Industry Achievement Awards 2014 – Winners announced

The largest and most prestigious Water Industry Achievement Awards to date took place on Tuesday 1st April where 470 of the water sectors finest came together at the Hilton Birmingham Metropole for an outstanding night of celebration, networking and entertainment.

CPSA is pleased to have supported the event as sponsor for the Most Innovative Use of an Existing Technology category, won by APEM and United Utilities. Congratulations to APEM’s Stuart Clough and United Utilities’ Dave Champness seen collecting the award from CPSA Director Stuart Crisp (left) and host Patrick Monahan (right).

Congratulations to all 2014 winners:

  • Carbon Reduction Initiative of the Year: Thames Water
  • Community Project of the Year: Northumbrian Water Group
  • Customer Satisfaction Initiative of the Year: United Utilities
  • Data Project of the Year: Wessex Water
  • Engineer of the Year: Anthony Thomas, 4Delivery
  • Health & Safety Initiative of the Year: Thames Water
  • Most Innovative New Technology of the Year: Severn Trent Water, Echologics and Loughborough University
  • Most Innovative Use of an Existing Technology: APEM and United Utilities
  • Partnership Initiative of the Year: Southern Water, PN Daly and RPS Water
  • People Initiative of the Year: Balfour Beatty
  • Sustainable Drainage & Flood Management Initiative of the Year: Morgan Sindall plc, Dŵr Cymru Welsh Water & Ove Arup
  • Water Resource Mananagement Initiative of the Year: Balfour Beatty
  • Outstanding Innovation 2014: Severn Trent Water,Echologics and Loughborough University
  • Outstanding Individual Contribution to the Water Industry: Geraint Williams, Dŵr Cymru Welsh Water

vidual Contribution to the Water Industry: Geraint Williams, Dŵr Cymru Welsh Water

Posted by & filed under Pipes & Manholes.

The development of circular precast manhole systems was introduced by the precast concrete pipeline industry in collaboration with the supply chain to provide a value engineered solution. The new manhole system comprises a circular, precast concrete base unit and new thicker-walled chamber rings with watertight flexible joints. These have the benefit of superior quality as a result of being factory manufactured off-site; they can be installed in less time, for less money, they improve safety on site, are watertight, and need no concrete backfill surround. In addition they have up to 43% lower carbon footprint.

An award-winning innovation is the concrete Pipe Lifter. Fitting a concrete Pipe Lifter to an excavator enables precast concrete pipes to be offloaded and installed quickly and economically in around half the time with less cost and less hassle than traditional means. Vitally, using the concrete Pipe Lifter significantly improves site safety because there is no need for anyone to stand on the bed of the delivery vehicle during offloading, there is no need for anyone to stand in the trench during installation and there are no slings or chains to trap hands and fingers.

Take a look at our video showing the concrete pipelifter in action.

These recent innovations help to ensure that precast concrete gravity foul water and storm water sewer systems continue to deliver best value.

Posted by & filed under Design.

The longevity of concrete and the inherent robustness of precast concrete pipes has become an increasingly attractive characteristic as regulatory changes have focused increasing attention on the whole life value of assets.

Concrete pipeline systems have been in use for over 160 years. This has given us evidence of what has worked and what has not worked so well so that, over time, it is possible to eliminate problems and achieve higher and higher performance levels. This evolution over time has allowed concrete pipeline systems to deliver a lower risk construction solution.

In addition, in the White Paper “Water for Life”, published December 2011, DEFRA noted that 0.125% of public sewers were replaced each year between 2000 and 2008. If that rate of replacement continues, sewers installed today will take around 800 years to be replaced. Our own research indicates that the implications of this are only now starting to be recognised and the need to look at service life expectation for all pipe materials is an essential part of the design and procurement process.

Sustainability is also becoming increasingly important with government targets behind a relentless drive to reduce carbon emissions and other environmental impacts across all aspects of construction.

The CPSA has put down a sustainability marker by investing in independently certified research, using a recognised methodology, to assess the carbon footprint of concrete pipelines. The report concluded that concrete pipes have a CO2e per meter of 17.8kg for a 225mm diameter pipe and up to 592.1kg for 2100mm diameter pipe, which is up to 40% less than the generic figures for precast concrete given in many industry databases.

Of course, the carbon footprint of the manufactured pipeline product is only one part of the carbon footprint of an installation. Once on site, another critical factor is the installation process. Because concrete pipes are structural elements they are less reliant on the quality of the installation on site to create a structurally sound solution and will usually require less imported granular bedding material (compared with flexible pipes), which further reduces the carbon footprint.

On the CPSA’s main website there is a structural design calculator and a material cost calculator, which can help optimise pipeline designs to the lowest cost and make the job of the engineer simpler and faster.