The choice of bedding design and standard of construction is as critical to the success of a pipeline installation as the choice of pipe. Understanding its importance, but not understanding the choices available, can lead to over-specification. Bedding design is one area where it is possible to prove the extent of this impact and the CPSA Structural Design and Material Cost calculators can play an important role.
There are a range of bedding solutions – or Classes – that are acceptable depending upon the material from which the drainage pipe has been manufactured, its strength and performance characteristics, traffic loading and the depth at which it is installed.
Bedding is particularly important for flexible pipes, such as sewer pipes manufactured from HDPE. This is because pipelines constructed with flexible pipes need to derive a significant proportion of their structural strength from the embedment either side of the pipeline to prevent them deflecting excessively under load, a condition known as ovalisation, where initially the vertical diameter of the pipe reduces and the horizontal diameter increases.
As a consequence of their lack of inherent strength, flexible pipe installations depend heavily on a high quality installation where the construction is carried out precisely to the engineer’s specification where the surrounding embedment takes the majority of the pipeline’s designed loading.
To help make the options more transparent, CPSA has developed a web-based Structural Design Calculator tool to help with the selection of appropriate bedding Classes for buried pipelines and a second tool – the Material Cost Calculator – to enable a clear cost comparison of different solutions.
Using these calculators recently allowed Leeds based ground worker and civil engineer Athena Civil Engineering to take the initiative on a new housing development in Roundhay near Leeds.
Using the CPSA Structural Design and Material Cost calculators, Athena was able to determine the optimum bedding design for the project. Consideration was also given to the excavated material from the trench, which was deemed suitable for backfill purposes.
To learn more about how Athena used the CPSA on-line calculators please read the full case study.
To download the CPSA Calculator App for portable devices please click here.
CPD – Continuing Personal or Professional Development – is the term that describes a commitment to structured skill enhancement and personal or professional competence.
CPSA currently offers industry professionals the choice of four CPD presentations independently accredited by Construction CPD Certification Service. 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. The presentations are delivered by Stuart Crisp, CPSA’s Business Development Director. To book a seminar, please complete the booking form or contact CPSA on 0116 232 5170 or email Stuart Crisp directly at email@example.com.
1. “Choosing the right pipeline system – now and for the future”
The areas covered include:
- Installation (capital) and operating costs.
- Structural and hydraulic design.
- Durability and lifetime operational performance.
- Quality and Standards.
2. “Embodied Carbon Emissions in Concrete and Other Pipeline Materials”
- Explains the fundamentals of carbon accounting and the data required to produce a carbon footprint.
- Identifies recognised 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.
3. “Surface Water Management using proprietary precast concrete SuDS systems”
This seminar provides an understanding of the legal framework driving changes in the design and construction of surface water management systems in the UK and the basic principles associated with sustainable drainage systems (SuDS) and their ownership, operation and maintenance. In this context, proprietary precast concrete SuDS components and systems will be identified and their specific uses examined.
4. “Optimising Pipeline Bedding Design to Achieve Installed Cost & Carbon Efficiencies”
This seminar demonstrates that substantial savings in pipeline installation costs and embodied carbon can be achieved through the effective use of structural design and the resulting selection of an appropriate pipeline embedment detail relevant to the pipe material and strength.
Modern drainage asks a lot of its materials. You need a system that’s totally reliable, easy to install, cost – effective, sustainable and compliant with all the relevant standards. It’s no job for a lightweight. That’s why concrete is still the UK’s best choice for sewerage systems. Concrete offers strong, stable, sustainable performance backed by over 150 years of proven success.
The Concrete Pipeline Systems Association (CPSA) has published a revised version of its comprehensive Technical Guide on the design and installation of concrete pipeline systems.
This latest edition of this indispensable publication will be essential reading for asset owners, designers and installers of concrete pipeline systems. This version has been updated to include the latest industry specifications and examples of best practice. It has also been completely redesigned and with new illustrations to improve clarity and to make it easier to use.
To help users access information quickly and easily, the Guide has been divided into five sections:
System Design – This includes information on the hydraulic design of surface and foul water drainage systems, an introduction to Sustainable Drainage Systems (SuDS), pipeline structural design and bedding material selection; and the design of manholes.
Installation of pipes in trenches – This includes advice on planning and sequencing operations, handling and storage, excavation and laying, jointing testing and ground reinstatement.
Installation of pipes using pipe jacking – This section includes a description of techniques and equipment and advice on product selection.
Installation of manholes – This incorporates advice on planning, handling and storage, construction, jointing and ground reinstatement.
The final section is a comprehensive list of references and further reading including industry Standards, specifications and references to other useful publications and industry bodies. Concrete pipeline systems are the material of choice for both foul water and surface (or storm) water systems and have been for over a century. With their proven long service life of more than 100 years users can be sure that installation and lifetime costs will be minimal. In addition to being cost effective, concrete pipes are also an environmentally friendly drainage solution, particularly when compared to plastic pipes.
A major advantage of using concrete pipes is that they are suitable for use with a wide range of bedding designs which can lead to substantial installed cost savings, faster installation and a lower environmental impact. Precast concrete’s inherent strength and durability can also help protect a pipeline system throughout its lifetime of operation and extend intervention periods for maintenance and replacement.
The Technical Guide provides essential information from the CPSA to design, install and maintain a concrete pipeline system. The Guide is currently available as a pdf download and includes hyperlinks to specialist information and additional design details.
CPSA members offer numerous components suitable for use within a sustainable urban drainage system.
On the CPSA website they are listed in a table indicating their functions within the appropriate Management Train. If you’re looking for specific product information contact the CPSA.
Useful Sustainable Urban Drainage System information:
Sustainable urban drainage systems are a natural method of controlling drainage in and around properties. SuDS work by holding back water that runs off from a site, allowing more natural processes to eliminate pollutants.
Appropriate implementation of sustainable urban drainage systems must deliberate a combination of techniques, supported by traditional drainage techniques. It is fundamental that all stakeholders within the construction of sustainable urban drainage systems consider the significance of the entire life maintenance and the use of suitable components that deliver sustainability and longevity.
Concrete pipeline systems manufacturers are determined to continuously innovate as the industry strives for improved pipeline and manhole construction quality and performance, delivering reduced waste, lower costs, faster build times and minimised environmental impacts.
The design flexibility of concrete pipe and manhole systems means that many special features can be incorporated in the factory and simply placed into position on site. These “offsite solutions” can replace lengthy in-situ operations, thus improving site safety and product quality, reducing waste, speeding up installation and reducing costs.
The new precast manhole base system yields environmental advantages; less concrete is used, there is less waste and less excavated material is disposed to landfill. An annual saving of over 22,000 tonnes of CO₂e is estimated in the UK if all manholes manufactured by members of CPSA changed to the new precast base system.
Two of our most popular online tools have been updated and we’ve also launched a new web App.
Providing access to the Structural Design and Material Cost Calculators for people on the move via iPhone or Android devices enhances the usefulness of these highly popular online tools. That is why you’ll now find the new web App available for download from the App Store and the Google Play Store. Changes to the original online calculators have been introduced to further simplify the calculation process and to improve the user experience. Designers and installers can now select the most economical buried pipeline solution with just a few swipes of the finger. The pipe factor of safety is now automatically determined in the Structural Design Calculator based on recommendations in BS 9295 and the Material Cost Calculator now provides users with the option to override the default values for bulk densities of excavated materials and imported granular bedding material. A further development is that results from the Structural Design Calculator can be input directly to the Material Cost Calculator and both calculators can export results into either a PDF or Excel file.
Check out the calculators and App:
The pressure to deliver a cost effective drainage installation with minimum environmental impact has never been greater, but despite this, some pipelines are still fully surrounded in expensive imported granular bedding when a more considered approach to the design and selection of the pipe material could result in the use of a less costly, lower carbon installation.
There are various classes of bedding, providing varying degrees of support for the pipe. What is required will depend upon the material of the pipe, the surface load (traffic, weight of the ground and any overlaying fill) and the reaction from the ground below to support the pipe.
For structural design purposes pipe materials are classified – in BS 9295: Guide to the Structural Design of Buried Pipelines – as either rigid, semi-rigid or flexible. Concrete and clay pipes are defined as “rigid”; ductile iron and thick-walled steel are all classed as “semi-rigid” while thermoplastic, glass reinforced plastic and thin-walled steel pipes are all classed as “flexible”.
Read more »
The practice of carbon accounting for pipeline products and sewerage construction projects is not new, but PAS 2080 introduces something new. In this blog we identify how five carbon accounting principles in PAS 2080 will change the sector’s understanding of embodied carbon.
Many water companies, highway authorities, other drainage infrastructure asset owners and supply chain partners already employ project carbon calculators. However, there are significant differences between these tools. PAS 2080 introduces a structured approach to tackle this inconsistency problem: It also provides clear boundary rules and a framework for whole life carbon accounting based on European standard EN 15978 where carbon claims can be verified and low carbon solutions can be robustly assessed.
PAS 2080 could mark the end of unproven claims for manufacturers of pipeline products. Data sources such as the Bath University ICE database will no longer be the main source of embodied carbon data. For manufacturers, PAS 2080 introduces five main principles which will change how embodied carbon is dealt with: These are
- Consistency in methodology
- The ‘Cradle-to-Grave’ approach
- Data Quality Requirements
- Third party accreditation
- Data challenging and re-baselining
FIVE FACTS THAT MAKE PAS 2080 DIFFERENT
PAS 2080 states “Consistent methodologies and data sources for carbon management and assessment are to be used to allow comparisons of emissions over time”. Users are obliged to assess inconsistencies and continuously challenge their suppliers for more accurate and robust data. The standard doesn’t embrace a specific methodology but European standard EN 15978 indicates that the European Commission’s TC350 methodology is probably the route to be taken by any future revision of PAS 2080. This means that the Bath University ICE Database may no longer be an automatically valid option as it compiles carbon values from a wide range of studies that are not aligned to EN 15978 requirements.
Read more »