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Multilayer Pipes - Solutions for utility piping systems

Multilayer Pipe (MLP) systems provide solutions to practical problems and offer maximum security in installation and jointing at minimum additional cost. Combining the best materials to meet specific loading conditions in the structure, they provide protection and long term durability.

Examples range from “peelable” external layers to protect the pipe from degradation and contamination during storage to tough inner and outer permanent layers to protect against scoring and gouging during installation and point load cracking during the service life of the pipe. Systems using a diffusion-resistant barrier layer for protection of the transported fluid against contaminated ground have also been developed. Other innovative possibilities include “detectable” pipes and improved pressure resistance.

MLP solutions enable the installer and system designer to reduce the overall cost of the project for a modest increase in pipe cost, and bring additional safety to the installation. The cost of the pipe is usually only a small proportion (9-15%) of the project cost, whereas digging and reinstatement costs are much higher.

Multilayer PipesThe development of Multilayer Pipe systems adds another chapter to the success story of polyolefin pipes in drinking water, gas, sewage and industrial applications.

Increasingly demanding conditions

Standard bedding /open trench

No sand backfill/stony soil

Slip lining DI or concrete pipes

Close fit systems / deformed pipe

Close fit-site deform - SwageliningPipe bursting & relining

Directional drilling operations

Make the most of Multilayer Pipes - with Borealis and BorougeWith more than 40 years of experience in providing polyolefin solutions, Borealis and Borouge are the ideal development partners for MLP products. Our unique range of PE and PP pipe materials, combined with technical expertise and market knowledge, enable pipe producers to meet the growing need of end-users with tailor made products.

The Borealis and Borouge Pipe Team can support you with:• Developing innovative solutions for improved

performance and differentiation in gas & water applications

• Expertise on material selection and the design of MLP structures for optimum product performance

Multilayer Pipes can satisfy increasingly demanding conditionsModern “no dig” pipe laying techniques can be tough on the PE pipe and in most cases it is not possible to examine the condition of the outside of the pipe after installation. In these circumstances the installer and system owner may be reassured by the presence of an external protection layer.

For example, directional drilling is often used to install PE gas and water pipes under rivers or farmers’ fields because it is cost efficient and minimises the disturbance to the environment. The addition of a sacrificial layer of PP to the outside of the pipe offers both protection and a good inspection tool for possible stone damage to the outside of the pipe. Similarly during insertion or “pipe bursting” old cast iron pipes using PE, a similar external

layer provides protection from the sharp shards of iron that could otherwise damage the new pipe.

Digging and reinstatement costs are very large elements in total project costs, which are increased dramatically if imported backfill material is used because of poor quality “as dug” material. Additional costs are also incurred as the original material dug from the trench has to be transported from the site, in some cases many kilometres, before it can be disposed of.

Cost effective alternativeA cost effective alternative is to use a PE pipe with a tough integral internal and/or external element that provides increased resistance to slow crack growth under point loading due to stones in the backfill material. This enables the “as dug” material to be used as backfill which reduces overall costs and greatly simplifies the logistics of the project.

A thin external “peelable” layer may also be used to improve electrofusion jointing quality in large diameter PE pipes. Making a good electrofusion joint necessitates removal of oxidised material from the outer surface of the pipe. However, this is difficult to do when installing large diameter pipes in the trench for e.g. a system extension or road crossing. If the underside of the pipe is not completely scraped or if it is contaminated, the joint will be poor and could even fail. But a pipe with a peelable layer can ensure that the outer surface is clean and within the correct dimensional specification. The joint is thus far more likely to be of good quality.

Increasingly demanding conditions

Standard bedding /open trench

No sand backfill/stony soil

Slip lining DI or concrete pipes

Close fit systems / deformed pipe

Close fit-site deform - SwageliningPipe bursting & relining

Directional drilling operations

Selecting the right materialsThe design of the multilayer solution needs to meet technical requirements and satisfy end-user needs. Selecting the right materials and applying them in the right way are the keys to success. This involves complex choice criteria, including performance, costs and compatibility of materials.

The following graphs can be considered as a first help to screen the possibilities:

1) Materials added in inner or outer layer to PE core material (integrated functional layers): • PE100-LS-H (PE100-HSCR1 with improved slow crack

growth resistance) • PE80 - bimodal MD (high SCG2 - but only as additional layer)

2) Materials added as outer layer to PE core material (protection layers):

• PP-B (incl. PP-HM3) • PP-R (incl. PP-RCT4) • PP-H

1 HSCR: high stress crack resistance2 SCG: slow crack growth3 HM: high modulus4 RCT: random (raised) crystalline structure with improved temperature resistance

Typical structure for Multilayer Pipes

Typical design solutions

Cost/Performance of different Multilayer Pipes solutions

KEY PROPERTIES FOR MATERIAL SELECTION> Hydrostatic pressure

test data> Slow crack growth

test data> Rapid crack

propagation test data for single and multiple layers

> Point load test data> Abrasion/scratch

testing> Weldability testing> Delamination testing

Preferred materials for Multilayer Pipes

Borealis and Borouge choice of materials:Preferred materials for Multilayer Pipes

PE100 Colour Density Comments

BorSafe™ HE3490-LS-H Black 959 superior resistance to slow crack growth

BorSafe™ HE3494-LS-H Blue 951 superior resistance to slow crack growth

BorSafe™ HE3490-LS Black 960

BorSafe™ HE3494-LS Blue 953

BorSafe™ HE3492-LS Orange 952

PE80 Colour Density Comments

BorSafe™ HE3470-LS Black 956 bimodal HDPE

BorSafe™ ME3440 Black 951 bimodal MDPE with high resistance to slow crack growth

BorSafe™ ME3444 Blue 943 bimodal MDPE with high resistance to slow crack growth

BorSafe™ ME3441 Yellow 942 bimodal MDPE with high resistance to slow crack growth

PP materials for Multilayer Pipes

PP-H Colour Designation Comments

Beta-PP™ BE60-7032 Grey Grey MRS 10 [MPa] high impact strength

PP-R Colour Designation Comments

RA130E Diverse MRS 10 [MPa] several colour shapes available, lower adhesion to PE layer

PR-RCT Colour Designation Comments

Beta-PPR™ RA7050 Grey MRS 11,2 [MPa] good impact strength, new PP-R generation

Beta-PPR™ RA7050-GN Green MRS 11,2 [Mpa] good impact strength, new PP-R generation

PP-B Colour Designation Comments

BorECO™ BA212E Natural PP-HM high impact strength, high scratch resistance

BorECO™ BA415E Natural PP-B high impact strength

BA202E Natural PP-B

Combining materials in an MLP structure efficiently addresses installer and end user needs, and brings added value to the project e.g. lower installation costs by enabling “as dug” material to be used as backfill, or additional security in joining and long-term performance.

With our knowledge and wide range of polyolefin materials, we can help pipe system producers to develop practical and profitable MLP solutions for utility piping systems.

Borealis AG IZD Tower, Wagramerstrasse 17-19, A-1220 Vienna, Austria. Tel: +43 1 22 400 000 Fax: +43 1 22 400 333

SALES & MARKETING Singapore (Head Office) Borouge Pte Ltd 1 George Street #18-01 Singapore 049145 Tel: +65 6275 4100 Fax: +65 6377 1233 Email: info@borouge.com

Disclaimer The information contained herein is to our knowledge accurate and reliable as of the date of publication. Borealis and 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 Borealis and Borouge except if in writing and signed by a duly authorised Borealis/Borouge employee.

Insofar as products supplied by Borealis and 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 Borealis and 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 Borealis and 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@borealisgroup.com Visit www.borealisgroup.com | www.borouge.com or call: +43 1 22 400 000 | +65 6275 4100

Borstar® is a registrated trademark of Borealis A/S.BorSafe, Beta-PPR, Beta-PP, and BorECO are trademarks of Borealis A/S.

About Borealis and Borouge

Borealis and Borouge are the leading suppliers of advanced polypropylene and polyethylene pipe system solutions.

Through the close dialogue with our customers and stakeholders, we have developed a broad and innovative product

and service portfolio over the last 50 years. Our applications cover water and gas distribution, waste water and sewage

disposal, chemical and industrial pipelines, in-house plumbing and heating as well as pipe systems for oil and gas

exploration and transportation. Through our close relationships with our customers & partners we strive to deliver a

steady stream of innovative pipe and fittings solutions that add real value for all members in the value chain.

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