Notice: This blog piece was created prior to the formation of the British Precast Drainage Association.

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The manhole system the drainage industry has been waiting for

The UK concrete pipeline systems industry has  introduced a new precast manhole system packed with many benefits that will satisfy designers, contractors and operators alike.

  • Reduced construction time
  • Decreased installation costs
  • Improved safety on site
  • Superior quality, reduced maintenance
  • Watertight –reduced running costs at treatment works and pumping stations
  • Reduced carbon footprint

Traditionally, manhole construction has required the base to be formed in-situ where building of the channel, connections and benching occurs in the trench, often in wet and unpleasant conditions.  The process can take around 40 hours per manhole and is not always successful, particularly in terms of leakage where egress of waste water can lead to contaminated groundwater and ingress can contribute to the common problem of overloaded sewer networks plus increased energy usage and running costs at treatment works and pumping stations.

The new manhole system comprises a precast concrete base unit, complete with channel and benching with predetermined combinations of inlet(s) and outlet and new chamber rings with watertight flexible joints and no lifting holes, thereby removing points of possible leakage.Both base units and chamber rings are made with thicker, stronger walls.  The robust design means that the requirement for a concrete surround is eliminated, unless specifically required.  The excavation is backfilled sooner and there is less need for men to work in confined spaces.  This reduces time spent in the excavation, further improving site safety and reducing installation costs.

Installation of the whole system is speedy and efficient.  Once in position, wet trades are eliminated, formation of benching on site and sealing of lifting holes is avoided and follow-up operations can start immediately.  Field trials indicate that time savings of over 30% can easily be achieved, particularly when installed without a concrete surround. The system also yields environmental advantages as less concrete is used, there is less waste and less excavated material is disposed to landfill.  An annual saving of over 15,000 tonnes of CO2 is estimated in the UK if all manholes manufactured by members of CPSA changed to the new precast base system. The quality of material and finish is well above that normally achieved on site and the full system is manufactured under factory conditions by third party certified companies to ISO 9001 quality management system.  Products are Kitemarked  to BS EN 1917:2002 and BS 5911-3:2002 Concrete Manholes and Inspection Chambers and tested under laboratory conditions.UK Water Companies have embraced the new precast manhole system and given their acceptance to use the design for new projects in lieu of traditional in-situ concrete construction.  Full acceptance is anticipated throughout the UK in the near future.

For further details about precast manhole bases and product availability, please contact CPSA on 0116 253 6161

Eco project adopts sustainable Easi-Basefor manholes

Cawrey Homes have been building houses in Ratby, Leicestershire since 1968, completing over a 1,000 new build and refurbished properties all to an exacting high standard and using the most energy efficient and cost effective materials available. The most recent development of 36 homes have all been designed to meet the Code for Sustainable Homes – Level 4, a sustainability standard that will be mandatory from 2013.

In recognition that the total build extends below ground to include storm and waste water drainage, the house builder in conjunction with its civils ground worker, M&J Beddard Construction, was quick to see the benefits FP McCann’s Easi-Base manhole system could bring by fitting into the sustainability criteria for materials.

The DN 1200 Easi-Base addresses a long-standing problem associated with traditional methods of manhole construction. Labour intensive, in-situ practices typically taking up to 36 hours are eliminated by the fully integrated unit which can be installed and connected in a matter of minutes. There are also considerable savings associated with reductions in embodied energy and embodied greenhouse gas emissions due to reduction in materials use and installation efforts.

The precast concrete base complete with channels and benching formed into a polypropylene liner is placed on a formation comprising compacted granular material. Pipe connection is made simple as connection bells are cast into the base for the specific pipe in use, thus allowing the ground worker to simply push the pipe into the base via the sealed connector. A watertight seal is instantly achieved. Water flows through the unit via a 1% preformed fall in the channel exiting at the outlet point. Conventional methods of constructing the manhole above the base are then followed, with precast concrete chamber rings placed directly on top.

In total, 12 DN 1200 Easi-Base units were supplied to the Ratby scheme, mainly for the site foul and storm system, however the ground worker was so impressed with Easi-Base, that Severn Trent Water was persuaded to use the product in adopted sewers. Each unit was installed and connected within 30 minutes.

John Cawrey, MD of Cawrey Homes commented, “The Easi-Bases have helped to speed up drain-laying and have reduced time spent benching manholes. The base being pre-formed, can be set and left ready for inspection once the cover is on.The system saves on labour and materials; there should be less time spent ‘snagging’ chambers prior to formal adoption by the water company.”

Learn about Carbon Footprinting and gain CPD hours, for free!

The CPSA training programme for industry professionals has been extended with the launch of a new CPD accredited presentation “Embodied Carbon Emissions in Concrete and Other Pipeline Materials”.

Everyone today is talking about sustainability. The UK’s pledge to reduce carbon emissions by 80% by 2050 will place immense pressure on industry to deliver. Carbon reduction and efficiency targets are appearing in all sectors. However confusion is widespread and “Carbon Accounting” can still be considered in its infancy. The new CPD presentation:

  • Explains the fundamentals of carbon accounting and the data required to produce a carbon footprint
  • Identifies recognized information sources and indicates limitations to the reliability of some data
  • Includes a detailed analysis of pipelines and provides comparisons with alternative pipeline materials and installation methods
  • Provides an overview of other environmental impacts such as responsible sourcing, recycling and embodied energy

To register your interest or to learn more about the full CPD programme click

Perfect timing from CPM’s Perfect Manhole

CPM’s Perfect Manhole was ready and waiting for Laing O’Rourke  as they marked the spot at their £13 million Springwell Community School in Barnsley project and just 25 minutes later the manhole was complete, proving that the CPM’s Perfect Manhole not only saves on labour and materials but also time.

How to install Perfect Base in six images – the process took 25 minutes only

Precast Drainage Products Attracts visitors at the BEST/Infrastructure show

All members of CPSA took part at the Infrasructure Show at Birmingham’s National Exhibition Centre between the 18th and 20th of October last year. The show proved to be a success to members as a number of new precast pipeline products and innovations were exhibited at the show -, including different types of the new precast manhole bases currently produced by CPM Group, Stanton Bonna and F P McCann. F P McCann’s UK Precast General Manager, Andy Cooper commented, “Our stand and range of specialist  products on offer generated much interest, attracting a healthy cross section of business prospects from contractors and merchant groups, to civil engineers and consultants. We’ve had very good interaction with and encouraging feedback from our visitors, giving us plenty to follow up on in the coming weeks.”

Stanton Bonna launches Perfect Manhole video on YouTube

Now that the majority of water companies have approved Stanton Bonna’s new watertight manhole and pre-formed base, known as The Perfect Manhole System, the company has launched a video to demonstrate the ease of achieving a safe, rapid and consistently high quality installation.

Stanton Bonna’s short video, available on its web site and on You Tube, shows a typical installation to help contractors, specifiers and merchants to appreciate the benefits of the system, as outlined at the top of this Newsletter. The six minute film shows a straightforward step-by-step installation of:


  • a DN1200 factory made watertight base unit, pre-benched with a 167º channel bend, DN300 inlet and outlet holes with seals
  • DN300 concrete spigot and socket butt pipes
  • 1 no. 1000mm and 1 no. 500mm thick-walled watertight chamber rings
  • 1 no. cover slab



t was the first time that Yorkshire based contractor Peter Duffy Limited had installed the Perfect System and despite being unfamiliar with it, the total installation time was only 1¼ hours including all pipework and partial backfilling. As a concrete surround is not required with the Perfect System, contractors can continue pipe laying immediately, gaining substantial and valuable time over the traditional method of manhole construction. Stanton Bonna has also ensured that its sustainable Perfect Manhole System benefits from a low carbon footprint and a design life of 120 years. Click
here to view the video on You Tube or here to find it at Stanton Bonna’s web site.

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