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.
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.
One 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
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.
Susdrain.org 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.
We are a Susdrain Supporter
CPSA joined the impressive cross-sector group of organisations in 2014 dedicated to supporting the www.susdrain.org 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.
If our Blog in March and eBlast in May plus social media postings escaped your attention and you haven’t seen our ads and editorial coverage running continuously in the trade press since March, here’s another chance for you to reduce your pipeline installation costs and embodied carbon.
CPSA has produced a new CPD seminar “Optimising Pipeline Bedding Design to Achieve Installed Cost & Carbon Efficiencies”. The presentation brings CPSA’s total to four seminars independently accredited by the Construction CPD Certification Service and The Chartered Institution of Water and Environmental Management (CIWEM).
This new 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.
The seminar aims to provide the delegate with an awareness of the structural design fundamentals for buried pipelines and the main industry reference sources available. The presentation should lead to an appreciation of the importance of combining structural integrity with minimum installation costs and lower embodied carbon and how this can be achieved through an understanding and effective use of structural design.
To arrange a free CPD seminar, please visit http://www.concretepipes.co.uk/page/cpsa-accredited-cpd-programme
Will there ever be an end to the relentless series of claims by product manufacturers that their product has superior carbon footprint credentials compared with competitors’, only to be followed by those same competitors claiming superiority based on yet another set of studies?
And how do specifiers decide who to believe?
By way of an example, the concrete pipeline industry is fighting its own battle with plastic. In 2010 CPSA published a detailed report based on the most comprehensive study of its type ever undertaken, providing embodied carbon footprints for precast concrete pipes, manhole rings and cover slabs. This study was then used to produce two further reports providing carbon footprint comparisons between concrete pipes and plastic pipes and between alternative manhole construction methods.
The pipe comparison study indicates that concrete pipes have up to 35% lower cradle-to-site embodied carbon when compared with HDPE pipe using the same full granular (Class S) bedding design. However, rigid concrete pipes can often be used with alternative bedding designs using less imported granular material, whereas standard stiffness plastic pipes will invariably require Class S. The result of which is that the potential carbon (and installed cost) saving with concrete pipes can be even higher.
After several years silence, the plastic pipe industry responded. Using the embodied carbon values for concrete pipes from the CPSA study, an alternative set of values were presented for plastic pipes. These values were based on a much older “generic” study using Bath University’s Inventory of Carbon and Energy, taking an average across a wide spectrum of products and geographical sources; unlike the CPSA study for precast concrete pipes, there was no new study based specifically on the manufacturer’s own plastic pipe products. And the comparison did not include impacts for alternative bedding designs.
Using this generic data, the results of the study indicated a lower carbon footprint for plastic pipes.
But is this riposte valid? Is it right to use data specific to a single product type (CPSA concrete pipe study) and compare it with generic data across a wide spectrum that does not represent the manufacturer’s own product? Different accounting methods will lead to different results. Does it make sense to make a comparison where the results were derived by separate methodologies with different rules and boundary conditions?
Almost all UK carbon databases and calculators use data for plastic pipes that trail back to data for resins from a study in 2005 by TNO for Plastics Europe. Recently, the integrity of this data has been questioned as the allocations to distillate products used in the Plastics Europe study do not appear to comply with the rules set out in the construction industry’s most recognised methodology, EN 15804. The Plastics Europe study assumes that the plastic pipe manufacturer is located 100km from the source of the resin. For a UK plastic pipe manufacturer, this is extremely unlikely. Resin supplied from further afield, such as the Middle East and Asia will significantly increase the carbon footprint of plastic pipes manufactured in the UK due to higher emissions from grid electricity plus emissions associated with transport.
Be aware. The plastic pipe industry has not embraced EN15804, the main Standard for carbon accounting in Europe for construction products. Instead, they have elected to follow an alternative route via Product Environmental Footprints (PEFs). Maybe the numbers work out more favourable for plastic using PEF rather than EN15804?
Concrete pipes Vs Plastic Pipes. Which has the lower carbon footprint? Whose claims do you believe?
Welcome to the Summer 2015 issue of Pipelines
The popularity of precast manhole base systems is rising as users appreciate the many benefits they offer. However, there are still many installers, developers, specifiers and clients missing out.
If you are interested in reducing risk on site, cutting installation time and costs, improving quality and eliminating leakage and you are not using CPSA members’ precast manhole base systems, it’s time you took a closer look…
Stuart Crisp, Director, CPSA
Concrete manhole system, packed with many benefits that will satisfy designers, contractors and operators alike
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 confined spaces that can present a safety hazard for operatives frequently encountering wet and unpleasant conditions.
The process can take around 40 hours per manhole to complete and is not always successful, particularly in terms of water-tightness, where egress of waste water can lead to contaminated groundwater and where ingress can contribute to overloaded sewer networks plus increased energy usage, carbon emissions and running costs at treatment works and pumping stations.
These issues can be avoided by using the new circular precast concrete manhole base systems available from all CPSA members. They comprise a circular precast concrete base unit, complete with channel and benching with predetermined / bespoke combinations of inlet(s) and outlet and new chamber rings with watertight flexible joints and no lifting holes, thereby removing points of possible leakage.
Base units and chamber rings are made with thicker, stronger walls. The robust design means that the requirement for a concrete surround is eliminated in most cases, considerably reducing the total volume of concrete required and resulting in up to 43% lower(*) embodied carbon for the installation. 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 time and costs.
(*)CPSA Manhole Systems Comparison Report
The manhole system the drainage industry has been waiting for
Precast Concrete Manhole Installation
Installation of the whole system is speedy and efficient. Take a look at CPSA members’ demonstration videos
CPMs Perfect Manhole Installation
Fast, Safe and Efficient Installation of FP McCann’s Easi Manhole Unit
Stanton Bonna The Perfect Manhole System
Enviromental Advantages
Less concrete is used, there is less waste and less excavated material disposed to landfill. An estimated UK annual saving of over 22,000 tonnes of CO2e could be achieved if all traditional manhole components manufactured by members of CPSA changed to the new precast base system.
All systems are 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 and tested under laboratory conditions.
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 confined spaces that can present a safety hazard for operatives frequently encountering wet and unpleasant conditions.
The process can take around 40 hours per manhole to complete and is not always successful, particularly in terms of water-tightness, where egress of waste water can lead to contaminated groundwater and where ingress can contribute to overloaded sewer networks plus increased energy usage, carbon emissions and running costs at treatment works and pumping stations.
These issues can be avoided by using the new circular precast concrete manhole base systems, which are available from all CPSA members. They comprise a circular precast concrete base unit, complete with channel and benching with predetermined/bespoke combinations of inlet(s) and outlet and new chamber rings with watertight flexible joints and no lifting holes, thereby removing points of possible leakage.
Base units and chamber rings are made with thicker, stronger walls. The robust design means that the requirement for a concrete surround is eliminated in most cases, considerably reducing the total volume of concrete required and resulting in up to 43% lower(*) embodied carbon for the installation. 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 time and costs
Benefits of the Precast Manhole
• Improved safety on site
• Reduced construction time; c50% (min 20%)
• Decreased installation cost; c30% (min 15%)
• Superior quality; factory made in a controlled environment
• Watertight; reduced leakage = reduced energy consumption, operational carbon emissions and running costs at treatment works and pumping stations
• Typically, no concrete backfill/surround required
• Reduced embodied carbon; up to 43% per manhole
The Concrete Pipe Lifter is a cost effective, simple-to-use system, which has been introduced to the UK by CPSA. It is a chance to improve safety, reduce costs and increase productivity.
The Concrete Pipe Lifter is a collaboration across all members of the CPSA who are working to reduce risks and to increase efficiency during deliveries, offloading and installation of sewer pipes in open cut trenches.
Concrete Pipe Lifters connect to an excavator via a quick hitch attachment and have no motorized parts making it easier to maintain. The lifting arm is inserted horizontally into the barrel of the pipe and raised to make contact with the internal crown of the pipe. The clamp arm will press down onto the top of the pipe at the socket end and hold it in position.
The concrete pipe is lifted without using slings or chains and without the need for an operative working at height on the bed of a lorry during offloading. The Pipe Lifter can be used to install the pipe with no-one in the trench and to push the pipe home to ensure formation of the correct joint gap.. The pipe may also be tilted up to 30 degrees from horizontal and manoeuvred between struts on trench support systems.
The Concrete Pipe Lifter is suitable for standard UK specification BS EN1916 concrete pipes from DN 300 to DN 1200 and the Type 2 lifter is designed for larger pipes DN1350 to DN2000.
Concrete Pipe Lifters make handling and installing concrete pipes safer, faster, easier and cheaper.
For more information and videos on The Concrete Pipe Lifter visit us today.
Welcome to the Spring 2015 issue of Pipelines
In this issue we are focusing on the Concrete Pipe Lifter. For many, this incredible, award-winning piece of equipment may be an overlooked gem.
There is nothing more important than the safety of construction site operatives during the offloading and installation of pipelines. Often, the introduction of safer working practices can lead to lower productivity and higher costs. In contrast, the Concrete Pipe Lifter is a rare chance to greatly reduce risk on site with the combined opportunity to significantly increase productivity and reduce costs.
The sad news of the death of workman in Swindon during the installation of cast iron sewer pipes is a stark reminder of the real risks that workers are exposed to and the importance of proper risk assessments and safe working methods.
The Concrete Pipe Lifter is a major step towards safer, faster, cheaper pipeline installation. It must not be ignored.
Stuart Crisp, Director, CPSA
Lay concrete pipes quicker with less cost and less hassle
Traditional methods for lifting and offloading concrete pipes include the use of slings or chains connected to integrally cast lifting hooks built into the pipe. These methods require an operative on the back of a vehicle during offloading to connect the slings / chains to the pipe and in the trench during laying to disconnect the lifting tackle from the installed pipe. It is reported that more than 75% of major fall-from-vehicle incidents occur during loading and unloading activities. The HSE estimated in 2004/05 that the human and economic cost of reported fall from-vehicle incidents was over £36.5 million.
The Concrete Pipe Lifter is a simple-to-use, inexpensive system introduced to the UK by CPSA. It is a collaboration across all members of the Association who are actively driving to improve site safety and increase efficiency during the delivery, offloading and installation of sewer pipes in open cut trenches.
The Concrete Pipe Lifter is connected to an excavator via a quick hitch attachment and uses no motorised parts making it easy to maintain. The lifting arm is inserted horizontally into the barrel of the pipe and raised to make contact with the internal crown of the pipe. The clamp arm will press down onto the top of the pipe at the socket end and hold it in position. The pipe may now be lifted and transferred to a suitable storage location or placed into the prepared trench and jointed following the application of an approved joint lubricant to the pipe spigot, if required. The pipe may be tilted up to 30 degrees from horizontal and manoeuvred between struts on trench support systems. It can also be used to push the pipe home to ensure formation of the correct joint gap.
Find out how you can buy or rent the Pipe Lifter from CPSA’s supply partners here.
Manual Handling
Lighter weight products made from other materials may initially appear easier to use and some suppliers have suggested that these items can be used without the need for mechanical lifting equipment. In fact, according to Health & Safety Executive guidance on weight limitations for manual handling, many lighter weight products are in excess of the upper limit for safe lifting. In many cases, this means that HSE guidelines and Safety Best Practice are not being followed and the use of “light weight” as a marketing tool could lead to lack of appropriate risk assessment and safety management on site. CPSA’s Information sheet on Manual Handling offers information on this.
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