Polypropylene materials for Non-Pressure Sewage and Drainage Systems

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1 Polypropylene materials for Non-Pressure Sewage and Drainage Systems MEMBER OF

2 Polypropylene materials for non-pressure sewage and drainage systems Market trends Over 15 years ago it was established that a piped sewage system provided a major improvement to public health. Today, however many of our sewers in the major cities are cracked and leaking into the environment. Most old sewer pipes are made from rigid materials like concrete or clay that are brittle and fail due to stone impingement or ground movement (see fig. 1). The generation of sulphuric acid also causes internal corrosion of concrete which further weakens the structure and is a major problem in hot dry climates. Ground movement and tree root intrusion are also problems for traditional sewage systems. Fig. 1: Rigid pipes fail in a brittle mode Steel Why PP for Sewage and Drainage Systems? Polypropylene (PP) like polyethylene (PE) is a polyolefin material that is easily processed to form pipes and fittings. PP is stiffer than PE and is therefore ideal for producing non-pressure pipes and forming the socket joints, which are usually preferred by the installer. To prevent tree root penetration or protect systems against earthquake damage PP pipes can be welded using standard butt fusion welding equipment. Iron Concete Clay GRP PVC PP Specific Weight - kg/m3 Fig. 2: Specific weight of sewer pipe materials The benefits of PP materials for sewage pipes: Concrete Chemical Resistance Polyolefin materials are very resistant to Iron sulphuric acid erosion indeed PP pipes or sheets are used to or protect concrete sewer pipes. Steel Specific weight PP has the lowest specific weight of all sewage PP Clay pipe materials producing a stiff lightweight system that is easy to install (see fig. 2).,5 1 1,5 2 2,5 3 3,5 Wall roughness factor Fig. 3: Flow characteristics of different pipe materials Hydraulic flow PP pipes are very smooth and have the lowest friction factor of all sewer pipe materials. Therefore, solids can be transported even at low fluid flows, which is important in hot dry climates like the Middle East (see fig. 3). Average abrasion (am in mm) 2, Abrasion resistance Polymers such as PP have a much higher resistance to abrasion than concrete, clay or iron pipes. This is particularly important in countries like the Middle East where sand is trapped in the sewer and drainage systems (see fig. 4). 1,5 Flexibility PP is tough and flexible and will not crack or break at 1, moderate levels of deformation, whereas concrete and clay pipes which are very brittle will fail. Using Glass fibre Reinforced Plastic (GRP) pipes the deformation has to be strictly limited to prevent cracking and water penetration which will lead to structural breakdown.,5 MC-DUR lined cement pipe FRP pipe Cement pipe Weldability where tree root intrusion is a serious problem, welded PP pipes systems can be used forming an impenetrable barrier to tree roots. Clay pipe PVC-pipe,25 PP or HDPE pipe n in 1 Number of load cycles (n in 1) Fig. 4: Abrasion resistance of different pipe materials

3 PP Sewage and Drainage System Solutions The principle design characteristic of a non-pressure pipe is its ring stiffness which is a measure of the pipes resistance to applied loads. The ring stiffness of the pipe is a combination of the stiffness of the material and the structural design of the wall. In order to provide the optimum stiffness for minimum weight different designs are used for different size ranges of pipe. Domestic waste water systems Fig. 5: Silent Internal PP waste system in high rise apartments Waste pipes in the home are often produced using PP materials to cope with the high temperature discharge from dishwashers and washing machines. In high rise luxury apartment buildings it is also important that the waste system is a silent system. This may be achieved using a multilayer pipe with a mineral filled polypropylene in the core layer which provides sufficient sound insulation to meet the requirements of the German DIN 419 standard. Smaller diameter sewer pipes Small diameter PP sewage pipes ( mm) are usually of solid walled construction with socketed ends for easy connection (see fig. 6). In recent years high modulus PP-B HM materials have been developed, which provide the ideal balance of stiffness, impact strength and long term properties for non-pressure sewage and drainage pipes. These materials allow the wall thickness of the pipe to be reduced for a given stiffness class and therefore are more competitive against other materials. Fig. 6: Solid wall PP sewage pipe Intermediate sized structured wall pipes For larger diameters (25 12 mm) structured wall designs are usually used to improve the stiffness to weight ratio and thereby reduce the cost per metre. Common designs include ribbed pipes ( Ultrarib ) or twin walled pipes with a corrugated outer and smooth inner wall. To optimise the design of the pipe corrugation, profile design needs to be matched to the material stiffness. A number of specialised machine manufacturers such as Unicor, Fränkische and Corma offer equipment and advice on how to produce these pipe products. Large diameter non pressure pipes Fig. 7: Structured wall sewage pipes At very large diameters (8 4, mm) it is usual to use a spiral winding process rather than a conventional corrugator to produce the pipes. The pipe is constructed from an extruded PP or PE profile that is wound onto a mandrel and welded to the adjacent spiral. In this way it is possible to produce pipes of up to 4, mm in diameter. European equipment manufacturers such as Bauku and Krah offer expertise and equipment for the manufacture of such pipes. Fittings for sewage and drainage systems Fig. 8: Large sewer fitting constructed from spiral wound pipe and PP sheets Plastic solutions are available for all the fittings commonly used in sewage and drainage systems. In smaller sizes fittings are usually injection moulded using PP-B materials to produce bends, elbows and inspection chambers. In larger sizes extruded shafts are fitted into rotationally moulded manhole bases to replace brick or concrete manholes with the saving of considerable time and construction costs. Where very large fittings are required they are usually fabricated from rotationally moulded pipes and extrusion welded PP-B sheets. The PP-B sheets may be produced using standard sheet extrusion equipment and recent trials show that BorECO materials perform very well and make excellent sheets.

4 Materials for Sewage Applications PP Grades BorECO BA415E This is an intermediate stiffness PP-B material designed specifically for the production of twin wall sewage and drainage pipes. It will produce high quality products at high output rates. BorECO BA212E This is a high modulus PP-B HM material specifically designed for the production of non pressure sewage and drainage pipes. Due to its higher stiffness it provides a 15 % weight saving against standard PP-B and a 27 % weight saving against PVC. Commercial Reference Material Type Modulus Application BorECO BA212E PP-B HM 17 High stiffness extrusion grade BorECO BA415E PP-B 15 Intermediate stiffness for twin wall pipe extrusion PE Grades BorSafe HE349-LS This is a PE1 pipe compound providing an excellent balance of production and end use properties. It is a high output material which is ideal for producing liner pipes for renovating gas, water and sewage systems. Borsafe HE349-LS-H This PE1 pipe compound has exceptional resistance to stress cracking making the pipe less vulnerable to failure due to installation damage. Ideal for the outer layer of a multilayer pipe installed using directional drilling or pipe bursting techniques. BorSafe HE349-IM This is a PE1 compound with improved flow properties, which makes it ideal for the production of injection moulded fittings. The higher flow enables a lower melt temperature to be used which reduces built in stresses (lower scrap rate) and the production cycle time (lower costs). Commercial Reference Material Type Colour Application BorSafe HE349-LS PE1 Extrusion all pipe sizes 63 2 mm BorSafe HE349-LS-H PE1 High SCR Extrusion pipes for demanding conditions BorSafe HE349-IM PE1 High flow Injection moulded pressure fittings Some useful web sites and references Borouge Borealis Unicor GmbH Fränkische GmbH Corma Inc. Bauku Krah Plastic Pipe Systems The Gulf Plastic Pipes Academy Plastics Pipes for Water Supply and Sewage Disposal Book by Lars-Eric Janson, 23 Dreiling, G. BorECO Polypropylene for sewage pipe systems Dubai Plast Pro, April 27 Barresi, S & Ek, C-G Plastics Pipes XII, April 24 Large diameter spirally wound PP sewerage pipes installation in Italy Taha, Y. PP Sewage Pipes Ensuring a Healthier Future in Asia and the Middle East Plastic Pipes XV, Vancouver, September 21

5 About Borouge Borouge is a leading provider of innovative, value creating plastics solutions. A joint venture between the Abu Dhabi National Oil Company (ADNOC), one of the world s major oil and gas companies, and Austria based Borealis, a leading provider of chemical and innovative plastics solutions; Borouge is a groundbreaking international partnership at the forefront of the next generation of plastics innovation. With its base in the United Arab Emirates and Marketing & Sales head office in Singapore, Borouge employs approximately 1,7 people representing more than 4 nationalities and serving customers in more than 5 countries across the Middle East, Asia-Pacific, Indian sub-continent and Africa. Building on Borealis unique Borstar technology and experience in polyolefins for more than 5 years, Borouge provides innovative, value creating plastics solutions for infrastructure (pipe systems, and power and communication cables), automotives and advanced packaging. In 21 Borouge tripled its annual production capacity in Abu Dhabi to 2 million tonnes and together with Borealis has an annual manufacturing capacity of over 5.4 million tonnes of polyethylene and polypropylene. The current Borouge 3 expansion project will be completed at the end of 213 resulting in an additional capacity of 2.5 million tonnes per year (t/y) being fully operational by mid Borouge is also investing in plants and logistics hubs in Asia and an Innovation Centre in Abu Dhabi. Focused on our company mission, Value Creation through Innovation, we ensure that our customers throughout the value chain, around the world, can always rely on superior products and security of supply. Borouge is committed to the principles of Responsible Care and together with Borealis proactively contributes towards addressing the world s water and sanitation challenges through their Water for the World initiative. Visit and see how we are Shaping the Future with Plastics. Borouge PF BR 224 R EN Disclaimer The information contained herein is to our knowledge accurate and reliable as of the date of publication. Borouge extends no warranties and makes no representations as to the accuracy or completeness of the information contained herein, and assumes no responsibility regarding the consequences of its use or for any printing errors. Our products are intended for sale to industrial and commercial customers. It is the customer s responsibility to inspect and test our products in order to satisfy himself as to the suitability of the products for the customer s particular purpose. The customer is also responsible for the appropriate, safe and legal use, processing and handling of our products. Nothing herein shall constitute any warranty (express or implied, of merchantability, fitness for a particular purpose, compliance with performance indicators, conformity to samples or models, non-infringement or otherwise), nor is protection from any law or patent to be inferred. No statement herein shall be construed as an endorsement of any product or process. No one is authorised to make representations or give warranties or assume any other liabilities on behalf of Borouge except if in writing and signed by a duly authorised Borouge employee. Insofar as products supplied by Borouge are used in conjunction with third party materials, it is the responsibility of the customer to obtain all necessary information relating to the third party materials and ensure that Borouge products when used together with these materials are suitable for the customer s particular purpose. No liability can be accepted in respect of the use of Borouge products in conjunction with other materials. The information contained herein relates exclusively to our products when not used in conjunction with any third party materials. For more information contact: info@borouge.com or visit or call: BorECO, BorSafe and Shaping the Future with Plastics are trademarks of Borealis group. Borstar is a registered trademark of Borealis group. Borouge Pte Ltd 1 George Street #18-1 Singapore Tel: Fax: info@borouge.com