concrete manhole

Posted by & filed under Pipes & Manholes.

When inspection or maintenance of buried wastewater drainage systems is required a manhole is specified. They are most often built at the point where one pipeline connects to another, where a pipeline changes size, direction or gradient and at a spacing that enables equipment to be used effectively. Here we detail some advice for specifying manhole systems.

  1. Consider a precast concrete solution

It can take up to 40 hours to construct a manhole using traditional techniques. Construction in-situ like this can also involve working in wet and difficult confined spaces. This is where off-site manufactured precast concrete manhole base systems offer some big advantages. They are safer, quicker and cheaper to install. In addition, they are watertight, of consistently high quality, create less waste on site and have a lower carbon footprint.

  1. Each manhole should be correctly constructed for each specific location

Due to the precast concrete base being factory manufactured to a specific configuration, when the components arrive on site they can quickly, simply and safely be placed in position. This negates the need for lengthy site-based operations.

The BPDA estimate that a contractor using a precast manhole base system could save up to 50 per cent on installation time. Construction costs can also be reduced by 15 to 30 per cent, particularly when manholes are installed without a concrete or granular surround.

  1. Manholes should be compliant with appropriate Standards

The technical requirements for reinforced and unreinforced manholes are described in the European Standard BS EN1917:2002 Concrete manholes and inspection chambers, unreinforced, steel fibre and reinforced and the British Standard BS5911 Part3: 2010+A1:2014 Specification for unreinforced and reinforced soakaways.

This British Standard is referenced in Approved Document H of the Building Regulations, which deals with drainage and waste disposal. This document details the rules which construction of drainage and waste disposal systems must comply.

The BS is also referenced in Sewers for Adoption and the partner water utility publications throughout the UK. These require developers and installers to build drainage systems to a minimum standard and quality for adoption by the relevant water company.

The advantage of using a BS-compliant and Kitemarked precast concrete solution supplied by a member of the BPDA is that users can be sure that the product will comply with all necessary technical requirements.

  1. Will you choose a round or square manhole chamber?

One of the biggest advantages of using a concrete manhole is that concrete is very strong in compression. A circular precast concrete manhole exploits this trait. Its circular shape ensures that ground and hydrostatic pressure is evenly distributed around the circular shaft. This enables circular precast manholes to be installed to a far greater depth than precast manholes of ‘equivalent strength’ with flat sides and corners.

  1. Consider the need for access

Whatever the shape of the manhole, if it includes a ladder or step irons for access then users need to be aware that the Health and Safety Executive’s confined spaces regulations. These recommend a 900mm clearance between the ladder/steps and the back of the shaft.

Ladders and steps usually protrude by at least 100mm, so for compliance users will need to consider a circular manhole with a diameter no less than 1,050mm.

Precast manhole systems offer great versatility and are designed to accommodate all standard pipe materials and sizes. Existing precast manholes can even be retrofitted with new connections from future development without the need to replace the entire manhole.

  1. Minimise the need for granular backfill

The robust design and wide chamber walls of the factory manufactured precast concrete manhole base system means that the use of granular or concrete backfill can be eliminated, unless it is specifically required by the client. The excavation can be backfilled sooner using the soil that was excavated, thus making the installation safer and faster whilst simultaneously reducing the cost of backfill and disposal of the excavated material.

  1. Save on carbon emissions

Factory manufactured precast concrete manhole base systems also offer a significant saving in embodied carbon for the installation. The BPDA estimates that carbon savings could be as much as 43 per cent per manhole compared with traditional in-situ construction. A notable part of this carbon saving is the avoidance of concrete or granular backfill and the use of excavated soil.

The BPDA estimates that 15,000 tonnes of CO2 equivalent of embodied carbon would be saved annually if all manholes manufactured by the Association’s members changed from in-situ construction to the circular precast base system.

  1. Consider durability

The precast manhole base system is manufactured under factory conditions by quality assured processes. This ensures the finish and quality is to a higher and to a more consistent standard than could have been achieved on site. The combination of durable precast concrete and quality controlled offsite manufacturing process will ensure that a precast manhole system has a long service life.

For more information about concrete manholes visit the British Precast Drainage Association website.


Posted by & filed under eNewsletters & eBlasts.

When designing, installing and maintaining drainage systems we know that difficult questions can arise. What is the installed cost? What is the carbon footprint? What is the minimum cover depth? What is the service life? Just a few questions which we have been asked over the years.

When using precast drainage products, it is important that you get the right information for the job. We recognize that you may have some important questions. There is now a place on our website where you can find answers to the most frequently asked questions about precast drainage. If you can’t find the question you need answering, you can simply contact us through our brand new enquiry system and we will ensure that your enquiry will be dealt with by an industry expert.

BPDA aims to give users all the information they need to complete their project successfully. For more information on the new FAQ, Search and Enquiry system click here.

20 reasons

Posted by & filed under eNewsletters & eBlasts.

Since the formation of the British Precast Drainage Association from the merging of the Concrete Pipeline Systems Association and the Box Culvert Association, the case for precast concrete drainage systems is stronger than ever. The new updated version of 20 Reasons to Use Concrete brings together in one useful booklet key benefits and references for precast concrete pipes, manholes, box culverts, sustainable drainage systems (SuDS) and other related drainage components.

Concrete drainage systems are at the heart of our sewerage network. It has been this way since the early 1860s when the Victorians introduced sewers into our communities for the first time. Their longevity, proven for over 150 years is just one of a number advantages offered by concrete which include reduced installation and whole life cost, lower environmental impact, inertia and high strength.

Concrete drainage products address the needs of the designer, installer and asset owner and have evolved to meet new challenges. This new booklet from the BPDA gives 20 reasons why concrete is the right choice today and for the future.

To download the booklet please click here. Or to request a hard copy please complete the Literature Request Form.


Posted by & filed under Pipes & Manholes.

In any construction project, bad ground conditions can create a wide range of problems and can even bring construction to a halt. This is why when Peter Harding Construction began work at St Wilfreds Academy in Blackburn, they knew they needed a drainage solution. The solution had to combat the poor ground conditions, not hinder the efficiency of their work, and ensure the health and safety of their team of workers.

After evaluating the site it was decided that orifice chambers and Hydro-Brake chambers were needed. However, this created problems relating to budgets and offsite design. BPDA member Marshalls CPM offered a solution by providing a full package of sealed 1200mm and 15000mm perfect manholes. They also provided off-site solutions for orifice and Hydro-Brake chambers. This allowed for many problems relating to chamber overflow to be overcome.

The Perfect Manhole system was used where possible. However, eventually, it was decided that due to the unusual ‘S’ style shape of the channel, a 1500mm sealed Catchpit that utilizes an offset inlet and outlet would be well suited for the project as well.

In addition, the client was presented a variety of pipeline design options. While plastic pipework was considered, this required using Class S Bedding. It was settled that precast concrete pipes would be the most ideal solution. This allowed for a lower overall cost and a reduced environmental impact as precast concrete pipes were installed with Class N bedding, which meant use of imported aggregate could be reduced.

The final result was an effect drainage solution that improved the poor ground conditions and accelerated the installation of the drainage requirements.

To read more please visit the BPDA website.

box culverts

Posted by & filed under Construction.

When a housing development in Lincoln was set to create 374 homes, a question was presented as to what drainage solution to use. BPDA member Forterra came to the rescue by supplying around 600 precast box culverts to the development.

Forterra, who worked together with the main contractor, Daniel Charles Construction, designed the drainage system to take surface water run-off from the development. The water is run through channels to control chambers. It is then stored into three large storage tanks, and discharged to a drainage ditch alongside the A46. Almost 2 million litres of surface water can be held in the drainage system, making it the ideal solution.

Measuring 2 metres long by 1.2 metres wide, and weighing around eight tonnes, it was expected that the delivery and installation of the box culverts would be tricky. Partner this with the difficult to access site, and you might expect to run into some problems. However, Forterra’s expertise meant that delivery and installation went very smoothly, forming runs of around 90 metres in length.

The box culverts were installed in 2 stages to ensure efficient and correct installation. The project for Forterra lasted 18 months, resulting in a well performing complete drainage system that the Construction Manager, Tony Higgins, and end client, Taylor Lindsey Homes, were very happy with.

To read more please visit the BPDA website.


Posted by & filed under Uncategorized.

Precast drainage systems have always been associated with strength, durability and sustainability. However in Asia, traditional precast drainage components are demonstrating their versatility by becoming the basis for an affordable housing prototype.

James Law Cybertecture, a leading Hong Kong based architecture studio, has developed a prototype for low-cost housing solutions made out of concrete pipes. These micro homes are stackable and could slot into gaps between city buildings.

The project sees 2.5m wide precast concrete pipes transformed into 9.29-square-metre homes and equipped with doors that can be unlocked using a smartphone.

The architect James Law envisions these tubular structures being stacked up on top of one another, creating affordable starter homes for young people in vacant city-centre locations across Hong Kong.

He believes that young people could live happily in the tubes for one to two years and are perfect for those would can’t afford their own private housing.

“OPod Tube Housing is an experimental, low-cost, micro-living housing unit to ease Hong Kong’s affordable housing problems,” he said.

Although the OPod is still only a concept, a prototype has been developed to show how a typical home could look. Inside the curved concrete walls, the home contains facilities for living, cooking and bathing.

Due to a rising population and limited development space Hong Kong is currently facing a major housing crisis. High demand for accommodation, skyrocketing property prices, and land limited by the city’s island geography has led architects to become more creative with the space.

They cost around £11,000 to manufacture and they could be rented out for as little as £300 a month. This is in contrast to the £1,500 rent for a one-bed apartment in the centre of the city.

Because each tube is only 2.5 metres wide, they could easily slot into narrow gaps between buildings. In addition, each unit only weighs 20 tonnes so they can be lifted with a standard crane allowing them to be relocated with relative ease.

If you want any more information please read the article on Deezen here.

underground fires

Posted by & filed under Sustainability.

Fires do happen … and not just in buildings. Last year saw wildfires spread across Greenland, Los Angeles, Montana, Portugal and Canada. With wild fire devastation getting worse every year for several parts of the world, we are tragically seeing an increase a loss of both human and animal life. While the loss of life, livelihood, homes and nature are clearly the primary concern; there are other factors that we often don’t realize are a result of these wildfires.

California in particular is always hard hit by wildfire season; so much so that homes built in fire hazard severity zones must be built to fire-resistant regulations. While this certainly protects the above ground surfaces, we must also look at what is happening underneath the surface.

When a fire occurs, wildfire or not, underground drainage pipes can suffer from serious damage, particularly if the pipe is manufactured from high-density polyethylene (HDPE) or polypropylene (PP). If the pipes burn, they can add fuel to the fire, if they melt, they can cause flooding, mudslides and even sinkholes, causing even further problems.

With wildfires predicted to double over the coming decades, and many building fires occurring every day, is it good enough to create drainage systems out of HDPE, PP and other plastics materials? With so much effort being put into creating safe and fire resistant above ground structures, it is about time building regulations looked at the problems beneath the surface. After all, fire resistant buildings can be deemed academic if a sinkhole forms in the ground they stand on.

For BPDA, the solution is simple. Concrete pipes are the way forward. If a fire of any type occurs, concrete can withstand the high temperatures and remain functioning and in place. This not only prevents flooding, mudslides and possible sink holes, it also reduces the cost and time of the clean-up and rebuild operation. Furthermore, the use of concrete pipes reduces the fuel available from which the fire can feed, hopefully making it easier to control and reduce the spread of fire.

In your next construction project, consider underground fire risks. Certainly here in the UK it is extremely rare for us to experience a wild fire. However, given the poor fire performance properties of HDPE plastic pipes, is it really wise to specify these in any area with a fire risk? Any building is it at risk of fire, and the use of HDPE pipes could mean the fire spreads uncontrollably and at a faster rate.

Choose your drainage materials carefully.


Posted by & filed under Uncategorized.

A newly created trade association will represent the interests of the precast concrete drainage industry. The British Precast Drainage Association (BPDA) is formed from the integration of the Concrete Pipeline Systems Association (CPSA) and the Box Culvert Association (BCA) and takes its place as one of the specialist product groups within the British Precast Concrete Federation.

Stuart Crisp, Business Development Director of the BPDA is clear about the benefits: “While the two product groups have distinct characteristics, there is much common ground in the use of concrete products in drainage applications.  Bringing the two associations together allows us to combine our resources more efficiently to promote the benefits of precast concrete drainage solutions.”

A distinctive new logo marks the launch of the Association and although rebranding the wealth of technical data sheets and guidance notes will be a gradual process, the new website is now live and all information from both associations can be found at

“The concrete industry has some compelling product benefits to shout about,” continues Stuart Crisp. “Our mission is to provide measured and accurate information and to counteract situations where inadequate and misleading opinions prevail.”


Posted by & filed under Pipes & Manholes.

Precast concrete has been around for many years. This time-proven, strong, durable and sustainable material continues to develop as new products and systems are introduced helping to deliver safer, cheaper and faster build times with reduced environmental impacts.

The precast manhole system comprises a factory produced monolithic concrete base unit, supplied complete with channel and benching with predetermined combinations of sealed inlet(s) and outlet and a thicker-walled chamber ring, removing the need for concrete backfill whilst providing a watertight structure. Construction time from base to cover slab is typically around 30 minutes.

The award-winning concrete pipe lifter makes light work of the installation of drainage pipelines. Simply remove the bucket and attach to your excavator in seconds.

There are no hydraulic links or mechanical components. It makes offloading, handling and installing pipes safer, faster, easier and cheaper.

Visit our website for more information on manholes and the pipelifter.


Posted by & filed under Pipes & Manholes.

Precast concrete drainage products have enabled Highways England’s main project contractor Costain to safely deliver a new £192 million dual carriageway section of the A556 trunk road between the Cheshire towns of Knutsford in the south and Bowdon in the north. The dual carriageway enables this strategic route to bypass the villages of Tabley, Mere and Bucklow Hill. Over 50,000 vehicles a day use the 7km stretch of road, which is an important link between the M6 motorway at junction 19 and the M56 motorway at junction 7.

Costain’s design partner for the scheme was Capita. Along with the task of designing the new road, Capita was also responsible for developing a drainage design solution with the capacity to deal effectively with rainwater run-off from the new road.

The drainage design uses precast concrete surface water channels at the edge of the carriageways to convey rainwater run-off to a series of V-gratings and then into catchpits.

Over 750 precast concrete catchpits have been used on this scheme in both 1200mm and 1800mm diameter. Manufactured by Concrete Pipeline Systems Association member FP McCann the precast concrete units incorporate a pre-cored monolithic base fitted with watertight, flexible connector seals to allow concrete drainage pipework to be connected quickly and easily to the unit.

The scheme also includes over 100 Easi-Base precast concrete manholes. Where the run-off cannot discharge directly manholes are used, many incorporating flow control units, penstocks and pollution control devices.

These off-site manufactured solutions are quicker, easier and safer to install. As the system is manufactured under factory conditions and is quality assured, the units’ quality and finish are better than could have been achieved under site conditions. Users can be sure that the precast units comply with all necessary technical standards.

Simon Ellison, Costain’s sector director said: “These off-site manufactured precast concrete drainage chamber systems have helped us achieve our build programme and site safety targets. They are simple to install and the integrity of the finished units together with the cast-in openings and seals are integral to our long life, low maintenance drainage design for the A556 bypass”.

For more information on the Concrete Pipelifter and Precast Manhole Systems please visit their dedicated pages.