installation & tech. guidlines - alpha pipelines homealphapipelines.co.nz/pdf's/pe...

Innovation in polyethylene pipe systems for water, gas and other applications

GPSPOLYETHYLENE

TECH

NICA

LG0

009/

1InstallationInstallation& Technical& Technical

GuidelinesGuidelines

IntroductionGPS is part of the worlds largestmanufacturer and supplier of highperformance plastic piping productsand offers the best and most costeffective pipe systems for itscustomers. GPS specialises inpolyethylene pipe systems for gas andwater transportation in the utilities andindustrial markets.

In GPS, the amalgamation of three market-leading companies -Durapipe, Stewarts & Lloyds Plasticsand Calder - brings together over onehundred years of experience in thedevelopment, manufacture andmarketing of plastic piping, fittings,and associated products for low andmedium pressure applications.

Market OrientedGPS products find a broad range ofapplications in the industrial andutilities markets on a worldwide basis.The utilities of water and gasdistribution are important sectors forhigh integrity products where themaintenance of water quality and thesafe transport of gaseous fuels are ofparamount importance. Industrialapplications include alternative energyinstallations in landfill gas systems toeffluent transportation and mineralslurries. Products are widely used inpipeline installation, repair andmaintenance.

Many of the brands in the GPSportfolio have a long record ofinnovation in meeting the needs of thewater and gas utilities. One of theforemost pioneers in polyethylene pipesystems, GPS is continually improvingand updating its offering to meet theever growing needs of the distributionengineer, ensuring they stay at theforefront of world gas and waterdistribution/treatment systems.

Manufactured in the UK, our productsare sold to more than 60 countriesworldwide.

Customer FocusThe key to our success lies in acommitment to provide the highestquality service and support. We are a team of highly motivated andexperienced individuals.

We place the utmost importance inmeeting the needs of our customers,constantly evolving our extensiveproduct portfolio to meet the everchanging demands of the water andgas utilities, industrial and offshoremarkets.

QualityGPS is a results-driven business - its people, products and service.

Designed, manufactured and suppliedunder an BS EN ISO 9001: 2000accredited Quality ManagementSystem, GPS products comply withrelevant national, European andinternational product standards toensure complete peace of mind for ourcustomers.

The EnvironmentCommitted to sustainable manufactureand systems, GPS operates andmaintains an environmental policyfully accredited to ISO 14001.

World leaders in the design, manufacture, marketing and sales of high

performance, high integrity plastic and composite piping systems.

GPS

Certificate No. FM 34819

Certificate No. E 51385

GPSPOLYETHYLENE

C O N T E N T S

GPS PE Products Overview 2-5

Quality and Environmental Standards 6-7

Product Markings 8

Material and Pipe Properties & Compatibility 9-11

Pressure Ratings, Flow Characteristics & Testing 12-19

Squeeze-Offs of GPS PE Pipes 20

Health & Safety 21

Handling & Storage 22-24

Procedures & Techniques for PE Pipeline Installations 25-31

Electrofusion Jointing Procedures 32-34

Durafuse Jointing Procedures 35-37

FRIALEN® Large Diameter Electrofusion Couplers & Jointing Procedures 38-40

Durafuse Jointing Procedures for Tapping Tees and Branching Saddles (top loading and underclamped) 41-43

Butt-fusion Jointing Procedures 44-48

Friatop Assembly & Operating Instructions 49-51

Flanged Connections 52-53

Protecta-Line Preparation, Jointing Procedures & Testing 54-60

Secura-Line Preparation & Jointing Procedures 61

Push-Fast System Procedures 62-63

Duck Foot Bend Assembly Instructions 64

website: www.gpsuk.com email: [email protected]

Pages

GPSPOLYETHYLENE

Tel: +44 (0)1480 52121 Fax: +44 (0)1480 458829 Technical Support: +44 (0)1480 442620

GPS offers complete piping systems manufacturedprimarily from polyethylene for pressureapplications.

The advantages of polyethylene pressure pipesystems have been appreciated in the gas andwater industries and by general industrial users formany years. Polyethylene’s toughness, immunityfrom corrosion, excellent resistance to chemicalsand light weight have contributed to its continuedappeal for use in situations where cost-effectiveand reliable systems are required.

Polyethylene pipes and fittings from GPS offer thefollowing advantages:

• High quality approved products, designed andmanufactured within an approved and registeredBS EN ISO 9001: 2000 quality system.

• Wide choice of systems.

• Up to 16bar rated at 20ºC when carrying waterand certain other liquids.

• Up to 10bar rated at 20ºC when carrying naturalgas.

• No anchor or thrust blocks needed. (Mostsystems are fully end load resistant).

• Ease of use.

• Four jointing methods - Electrofusion, Butt-fusion, Mechanical Fittings and Push-Fast (amechanical integrated spigot and socket system).

Polyethylene systems from GPS are manufacturedto meet the exacting standards imposed by gas andwater bodies.

GPS polyethylene systems are available in differentcolours and are offered in high quality PE80polymer, formerly known as MDPE (MediumDensity Polyethylene) and PE100 (Excel) formerlyknown as HPPE (High Performance Polyethylene).Excel being the GPS brand name for pipe madefrom PE100 polymer.

G P S P O L Y E T H Y L E N E P R O D U C T S

2


GPSPOLYETHYLENE

ConventionalPE PipesPipes are available in6 and 12 metrestraight lengths.Other lengths can besupplied to order.Pipe up to 180mmOD is also availablein coils of 50m,100m and 150mand can be suppliedin longer lengths ondrums. Pipe can also be extruded with four co-axialstripes to identify the contents being conveyed or toidentify the application.

Pipes are extruded in two basic materials - PE80 (MDPE)and PE100 (Excel) in the following colours:

• Blue - For potable water supply below ground.• Yellow/Orange - For Gas supply below ground.• Black - For global water and gas supplies, UK potable

water supplies above the ground and industrial(sewage, mining and quarry) applications above andbelow ground.

Protecta-LineProtecta-Line is anaward winninginnovative PEpipeline solutionspecifically designedfor the safetransportation ofdrinking waterthrough brownfieldsites & other types ofcontaminated land. With WRAS and DWiapproval, the system provides total peace of mind to thehighest standards and meets all of the safety legislationdemanded by water companies and customers alike. Protecta-Line combines all of the advantages ofconventional high quality PE pipe with an aluminiumbarrier layer to prevent permeation and is offered in pipediameters from 25mm through to 180mm. Protecta-Linepipes can be butt fused where local water bylaws permit,or by any of 3 different types of fittings:mechanical compression up to 63mm, fluid compressionfrom 63m - 180mm & electrofusion above 63mm wherelocal water bylaws allow.

Secura-LineSecura-Line is apolypropylene coatedPE pipe originallydeveloped for pipebursting and otherapplications requiringextraordinaryresistance to externalabrasion, providingenhanced protectionagainst damage andeliminating the needfor pipe end cleaning and scraping prior to electrofusion.Manufactured from standard PE100 polymer with a 1mmlayer of polypropylene which can quickly and easily beremoved, Secura-Line saves both time and money in thefield. Secura-Line can be butt-fused using the sameparameters as standard PE pipe.

3

GPSPOLYETHYLENE


Sleeved Sub-CoilSleeved Sub-Coil is alow costrehabilitation systemfor distribution mainsand small trunkmains manufacturedby GPS in co-operation withSubterra (a divisionof EnterpriseManaged ServicesLtd) and United Utilities Ltd. Sleeved Sub-Coil is a PEliner which has been factory folded into a ‘C’ shape andheld in that form by a continuous thin sleeve. This foldedgeometry gives the annular clearance necessary to allowfast insertion into the host pipe. Pressurisation parts thesleeve allowing the subcoil liner to revert back to itsoriginal circular shape. The liner forms a close fit withthe host pipe, sealing against leakage and preventingfurther host bore corrosion.

DuraFuse -ElectrofusionFittingsDuraFuseelectrofusion fittingsare easy to use andoffer highperformance and arapid, convenient,means of joiningpolyethylene pipes.Their design ensuresoptimum meltpressure because the energising coils of wire are preciselypositioned to ensure uniform melting and to minimise therisk of accidental wire damage. Each fitting features abar code label to enable suitable electrofusion controlunits (ECUs) to scan the bar code in order to determinethe fusion parameters. DuraFuse fittings are offered inPE80 (MDPE) Yellow or PE100 (Excel) Blue or Black andin PE size up to 400mm.

In addition to the DuraFuse range, GPS also offers a rangeof larger diameter electrofusion fittings. The Frialen rangeis offered in Black PE100 with bar code labelling which isnecessary for fusion and data-logging purposes.FRIALEN® SDR11 fittings are rated at 10 bar for gas anduti 16 bar for water whilst SDR17 fittings are rated at5.5 bar for gas and 10 bar for water.

Long Spigot &Pupped FittingsThe GPS Long Spigotrange offers acomprehensivechoice of fittingssuitable for butt-fusion without theneed for pupping(Provided thatmachines withnarrow clamps areused). Products areoffered in PE80 Yellow, Blue or Black as well as PE100(Excel) Blue or Black. A range of fittings is also offeredwith factory fitted half metre pups to facilitate jointing onsite.

4


GPSPOLYETHYLENE

SlimFlange®

SlimFlange® is aunique productdeveloped by GPS toallow size-for-sizeconnection of a PEpipeline to a metalfitting or pipe, i.e.without any changeto the nominal bore.SlimFlange® featuresa steel reinforced PEface which allows thePE shoulder height to be reduced significantly, while at thesame time the strength of the joint is actually increased.SlimFlange® is available in both PE80 (MDPE) and PE100(Excel) complete with gasket and backing ring.

Calder JointingEquipment andToolsThe Calder brand is acomprehensive rangeof user-friendlyelectrical andmechanical toolingcomprising of electro-fusion control units(ECUs), clamps,scrapers and otherassociated tools forjoining polyethylene pipe. All ECUs are designed forarduous site conditions and are equipped with combinedcarrying and protective frames. Machines are availablefor both manual and automatic operation. Specialmachines can be supplied with the ability to read barcodes using a light pen in order to determine the fusionparameters of the particular fitting. These units alsoinclude data logging facilities to ensure traceability offusion data for retrieval at a later time and transfer to adatabase or printer.

Push-FastFittingsThe Push-Fast spigotand socket typesystem featuresindividualelastromeric sealingand internal griprings. Unlike similarspigot and socketsystems offered inother materials,Push-Fast resists theend thrust generated by the internal pressure, so anchorsor thrust blocks are not usually required. This product isoffered in both PE80 (MDPE) and PE100 (Excel)materials in blue or black and is rated up to 16bar. Thisproduct is not recommended for gas applications.

5

GPSPOLYETHYLENE


Q U A L I T Y

GPS operates a quality assurance system inaccordance with BS EN ISO 9001: 2000 which isaudited on a regular basis by BSI.

The quality assurance system imposes stringentstandards of control throughout design,development and subsequent production andinspection processes, as well as the provision ofCertificates of Conformity for all raw materials, i.e.polymer and resistance wire etc.

Products are subjected to the following range ofchecks and tests, some being applied to every pipeand fitting, whilst others are carried out on asample basis:

• Coupon tensile tests• Dimensional control• Hydrostatic pressure tests at 20°C and 80°C• Stress cracking tests • Surface finish• Crush tests carried out on pipe fused into

electrofusion sockets as part of jointperformance tests

• Joint pull-out tests

Detailed records are kept of dimensional andperformance tests for each production batch. Eachbatch is given a unique identification numberwhich is reproduced on every fitting or pipe.

We operate an environmental management systemthat has been successfully assessed against the BSEN ISO 14001 environmental managementstandard.

E N V I R O N M E N T

The GPS range of polyethylene pipes, DuraFuseelectrofusion fittings and long spigot fittings are approvedfor use in many countries. Examples of wheresecond/third party certification has been achieved aregiven below:

UK British Gas/NGT/Advantica Technologies LtdWater Regulations Advisory Scheme DWI Regulation 31

Argentina Argentinian Gas InstituteAustria ÖVGW/ÖN/ÖFI/TGMAustralia WSAABelgium BecetelCzech Republic TSUDenmark DSFrance GDFGermany DVGWGreece DEPAHungary Hungarian Mining OfficeItaly IIP-UNI (PE80 and PE100 (Excel))

AEMMalaysia Lembaga Air Perak

Ibupejabat, JabatanPenang Water Authority

Moldova Centrul de Expertiza TechnicaPoland IGNIGRomania Central LaboratoryRussia Hygiene ApprovalSpain Gas NaturalSweden TumabSwitzerland SVGW (PE100 (Excel))

For a more detailed listing of products covered by theseapprovals, please contact our sales department.

A P P R O V A L S

6

Certificate No. FM 34819Certificate No. E 51385


GPSPOLYETHYLENE

W A T E R S T A N D A R D S

Transco PL2 –Part 1 - 1998 – Specification for polyethylene pipe

and fittings for natural gas andsuitable manufactured gas

Part 4 - 1998 – Fusion fittings with integral heatingelementsPart 6 - 1997 – Spigot end fittings for electrofusion

and/or butt-fusion purposesPart 8 - 1998 – Pipes for use at pressures up to

7barTransco PL3 - 2002 – Specification for Self-anchoring

Mechanical Fittings/Joints forPolyethylene (PE) Pipe for naturalgas and suitable for manufacturedgas

ECE1 – Specification for electrofusioncontrol boxes

BGES/F2 – Specification for Main to ServicePipe Fittings (for use up to 2bar);

BS2494G – Specification for ElastomericMaterials used in the Manufactureof Seals’ (for gas mains and fittingsup to 7bar); (BSEN 682)

ISO161-1:1996 – Thermoplastic Pipes – nominaloutside diameters and nominalpressures.

ISO 4065:1996 – Thermoplastic Pipes – Universalwall thickness tables

ISO 4437:1997 – Buried PE pipes for the supply ofgaseous fuels.

BS ISO 11922-1:1997 – Thermoplastic pipes for theconveyance of fluids Dimensionsand tolerances. Metric series.

BS6437 - 1984 – Polyethylene pipes (type 50) inmetric diameters for generalpurposes.

BS ISO 8085:2001Part 1 General – Polyethylene fittings for use withpolyethylene Requirements pipes for the supply of gaseous

fuelsPart 2 – Spigot fittings for butt-fusion or

socket fusion using heated toolsand for the use with electrofusionfittings

Part 3 – Electrofusion fittingsBS EN 1555 – Plastic piping systems for supply of

gaseous fuels – polyethylene.

BS EN ISO 15494:2003 – Specifications for polyethylenecomponents and system.

BS6437 - 1984 – Polyethylene pipes (type 50) inmetric diameters for generalpurposes.

BS6572 - 1985 – Specification for blue polyethylenepipes up to nominal size 63 forbelow ground use for potable water.

BS6730 - 1986 – Specification for black polyethylenepipes up to nominal size 63 forabove ground use for potable water.

BS5306:Part 2 - 1990 – Fire extinguishing installations andequipment on premises.

WIS 4-24-01 - 1998 – Specification for mechanical fittingsand joints including flanges forpolyethylene pipes for theconveyance of cold potable waterfor the size range 90 to 1000including those made of metal orplastics or a combination of both.

WIS 4-32-08 -Issue 3:April 2002 – Specification for the fusion jointing

of polyethylene pressure pipelinesystems using PE80 and PE100(Excel) materials.

WIS 4-32-14 - 1995 – Specification for PE80 and PE100(Excel) Electrofusion fittings fornominal sizes up to and including630mm.

WIS 4-32-15 - 1995 – Specification for PE80 and PE100(Excel) spigot fittings and drawnbends for nominal sizes up to andincluding 1000mm.

WIS 4-32-17Issue 2 - 2001 – Polyethylene pressure pipes for

pressurised water supply andsewerage duties includingSecura-Line.(kite mark for waterapplications only)

DIN8074 - 1999 – Pipes of high density polyethylene(HDPE) type 2 – dimensions.

DIN8075 - 1999 – Pipes of high density polyethylene(HDPE) type 2 – testing.

DIN16963 Part 1-1980 – High density polyethylene (HDPE)fittings dimensions, type 2.

ISO4427-1996 – PE pipes for water supplyBS EN 12201 – Plastic piping systems for water

supply – polyethylene.BS EN 13244 – Plastic piping systems for general

purpose water, drainage andsewerage - polyethylene

UNI 10910:2001 – Polyethylene piping systems forwater distribution

WIS standards are Water Industry Specifications currently issuedin the UK by UK Water Industry Research Ltd.

G A S S T A N D A R D S

7

BS 6572

WIS 4-32-17

GPS polyethylene range is designed to comply with the requirements of one or more of the standards shownon this page.

GPSPOLYETHYLENE


Electrofusion FittingsWhere applicable, most fittings incorporate the followinginformation on the outer surface.

• Material designation

• Standard Dimension Ratio (SDR)

• SDR fusion range (max/min)

• Nominal size (mm)

• Weight (kg)

• Fusion time indicated underneath the following logo inseconds.

• Cooling time indicated underneath the following logo inminutes.

• Name and trademark

• Relevant certifying symbol and standards number

In addition to the above information, all productmanufactured within a specific batch is marked with anidentification number, unique to that batch

This unique number consists of 7 digits which can beinterpreted, as follows:

1 2 3 4/5 6/7

The last two digits of theyear

International Standard weeknumber

The day of the week: 1 = Monday7 = Sunday

Batch reference: the number of the batch in a

particular shift, usually 1.

Shift period: day = 1 night = 2

Product PackagingIn addition to information marked directly on the productsthe following information is supplied on the productpackaging.

• Fitting type

• Application information (Gas or Water)

• Certifying symbols and standards

• System voltage (if applicable)

• Pressure rating

PipesWhere applicable pipes incorporate the followinginformation marked indelibly, linearly, at intervals alongthe pipe.

GPS Pipe MarkingWhere applicable pipe incorporate the followinginformation marked indelibly, linearly, at intervals alongthe pipe. e.g.

P R O D U C T M A R K I N G S

8

GPS 180mm SDR11 PE100 S 14143004 H

Manufacturer/Trademark

Nominal pipe outside diameter (OD) in mm

Standard Dimensional Ratio valueSDR value

Material designation (i.e. PE80 or PE100)

Material manufacturer’sidentification code

Shift Code (an8 digit codedenotingMachine, Shift,Week & Year)

Plant Code

GPS pipe is also marked with the name of any industrystandard to which it conforms.

Blue water pipe also carries reference to the bar rating ofthe pipe (usually after the OD) and is marked at threeseparate intervals within the coding with the wordWATER for high visibility and identification purposes.

For identification purposes, Protecta-Line and Secura-Linepipes are also marked with four brown stripes to indicatethat they are multi-layered pipes.


GPSPOLYETHYLENE

9

Expansion and ContractionThe average coefficients of linear thermal expansionbetween 20ºC and 60ºC for PE80 (MDPE)(1.3 x 10-4 ºC-1)and PE100 (Excel)(1.5 x 10-4 ºC1) are approximately tentimes greater than for metal. Allowance must be made forthis when designing polyethylene pipeline installationswhere significant temperature variation is expected (eg.above ground). If the above length change is re-stated as8mm for PE80 and 9mm for PE100 (Excel) per 6m pipelength per 10ºC of temperature change, the magnitude ofpotential thermal movement can be better appreciated.In above-ground installations the natural flexibility of thepipe, coupled with judicious sitting of anchor and supportbrackets, will conveniently accommodate expansion andcontraction at changes of direction, etc. In installationswhere fully end-load bearing joints are used, thecompressive or tensile forces set up in the pipeline due toconstraint of thermal movement will not detract fromlong-term performance, but the effects of these forces on

M A T E R I A L P R O P E R T I E S & C O M P A T I B I L I T Y

MaterialsGPS manufactures polyethylene systems in both PE80and PE100 (Excel). The numbers relate to the MRS(Minimum Required Strength) values of the material.PE80 – This is the term used to denote the polyethylenematerial which has been widely used for gas, water andindustrial applications for many years. The terms MDPEand HDPE were commonly used for this material,although MDPE PE80, as historically supplied by GPS,has a much higher long term stress crack resistance thantraditional HDPE PE80.

PE100 (Excel) – This is a term used to denote highperformance polyethylene, and PE100 pipes are sold byGPS under the brand name of Excel. PE100 (Excel) is ahigher density material than PE80 and demonstratesexceptional resistance to rapid crack propagation as wellas to long-term stress cracking.

Moreover, the higher performance of Excel permits thinnerpipe walls than PE80 for the same operating pressure. Ittherefore uses less polymer and provides for a larger boreand increased flow capacity for a given nominal pipe size.This can result in significant cost savings at certain sizesand pressure ratings.

PE80 and PE100 (Excel) are not recommended forcontinuous pressure operation at temperatures above60°C for liquids, including sewerage and industrialeffluents, or 30°C for gaseous fluids. PE100 (Excel) hasadvantages over PE80 at low temperatures, since it isextremely crack resistant down to -30°C. Whenconsidering applications which exceed the limits statedabove, ask our Technical Support Department for advice.

Property Method PE80 PE100of Test Units MDPE (Excel)

Melt flow rate -2.16kg load BS2782 g/10min 0.2 <0.15

ISO 1133

5kg load BS2782 g/10min 1.0 <0.5ISO 1133

Density BS3412 kg/m3 yellow 940 orange 951(Mean Values) ISO 1872 blue 943 blue 951

black 950 black 957

Tensile strength at BS2782 MPa 18 23yield ISO R527

Elongation at BS2782 % >600 >600break ISO 527

Flexural BS2782 MPa 700 1000Modulus ISO R527

Vicat softening point BS2782 °C 116 124

Brittleness ASTM D746 °C <–70 <–100temperature ISO 9784

Linear thermal expansion ASTM D696 °C 1.5 x 10

–41.3 x 10

–4

Thermal BS874 W/m°K 0.4 0.4conductivity DIN 52612

Further details may be obtained from GPS Technical Support Department.

Standard Dimensional Ratio (SDR)One of the items of information contained on both pipeand fittings is the standard dimensional ratio.

In all but the smallest sizes of PE pipe (< 25mm) theratio between wall thickness and outside diameter remainsconstant for a given pressure rating of the pipe. Thisrelationship, called the standard dimensional ratio or SDR,can be expressed as an equation:

SDR =nominal (minimum) outside diameter

minimum wall thickness

Example:

SDR 11 = 18016.4

16.4mm wall thickness

180mm OD

Relationship between wall thickness and outsidediameter (OD)

GPSPOLYETHYLENE


radius values apply only if pipe is bent in the samedirection as it was previously coiled.

InsulationPolyethylene is a good insulator and will help preventfreezing of liquid pipe contents to an appreciable extent.Even if freezing does occur, the pipe will not fail since itcan safely expand to accommodate increased volume.Nonetheless, the pipeline system may still need to beprotected against freezing temperatures to prevent flowrestriction. Should you require any information orassistance on designing a PE pipe system, pleasecontact our Technical Support Department.

Abrasion resistance of polyethylenePE has significant advantages over other pipe materialswhere internal resistance to abrasion is required - forexample if the pipe is intended for transporting abrasivemedia such as particulate slurry. This resistance toabrasion, combined with flexibility, ruggedness andimmunity from corrosion, makes PE ideal wheretraditional pipe materials would be unsuitable. Abrasionresistance depends on slurry characteristics and flowparameters, but is predictable in many cases.Polyethylene pipe has been used successfully for pumpedabrasive media such as fly ash, china clay slurry andvarious industrial effluents. In addition, it has been proven that, during installation,the abrasive elements of typical soils and backfills make anegligible impression on PE pipe. However in the unlikelyevent of a notch or groove being cut into the externalsurface by more than 10 per cent of the wall thickness,the pipe section should be rejected.

Chemical Resistance - GeneralPolyethylene material is renowned for its good resistanceto chemical attack. The degree of resistance to a specificchemical will depend on concentration, temperature andworking pressure, each of which will affect the long termlife of any system. Polyethylene does not rot, rust, pit,corrode or lose wall thickness through chemical orelectrical reaction with the surrounding soil. Polyethylenedoes not normally support the growth of, nor is affectedby, algae, bacteria or fungi.

In broad terms the most common harmful chemicals canbe grouped into oxidisers, cracking agents and certainsolvents.

Chemical Resistance - Special CasesSpecial care is required in industrial applications whereeffluents contain particular chemicals. Under certainconditions of pressure and temperature, the chemicalslisted hereunder may be detrimental or permeate the pipewall and taint water supplies. If you are in any doubt, seek the advice of our Technical Support Department.

Oils: animal; vegetable or mineral such aspetrol, creosote, turpentine andsilicone fluids.

10

pipe support, ancillary equipment and so on, must beconsidered and allowance made.The potential for thermal movement is a particular issuewhere a (fully end-load bearing) PE system is connectedto any non end-load bearing mechanically jointed system.It is essential that such transitions are securely anchored,to obviate the risk of any joints in the mechanicallyjointed system separating.It is also prudent to allow a newly installed pipeline timeto conform to ambient temperature before endconnections are made.

SupportRecommendations for maximum support spacing aregiven in the table below. They are based on a mid-spandeflection of 6.5mm when the pipe is full of water andassume a long term flexural modulus of 200MPa at anambient temperature of 20ºC. Pipe clips used foranchorage and support should have flat, non-abrasivecontact faces, or be lined with rubber sheeting, andshould not be over-tightened. The width of supportbrackets and hangers should normally be either 100mmor half the nominal pipe bore diameter, whichever is thegreater.

Pipe bending radii for PE The minimum bend radius for GPS PE pipes is 15 timesthe pipe OD under optimum conditions (ie. warm ambienttemperature and thick-wall/low SDR pipe). A more typicalsafe bending radius for SDR11 and SDR17 pipes is 25times, increasing to 35 times the pipe OD in very coldweather. For thin-walled SDR26 and SDR33 pipes, thesevalues should be increased by 50%. Electrofusion ormechanical joints and fittings should not normally beincorporated in sections of pipework which are to be bent.Instead a formed bend or elbow should be welded intothe pipeline in order to prevent excessive stress. In thecase of pipe supplied in coils or drums, the above bend

Above Ground Pipework Maximum Support Spacing (metres)

Pipe SDR11 SDR17 SDR2632mm 0.963mm 1.190mm 1.3 1.2

110mm 1.5 1.3125mm 1.6 1.4160mm 1.8 1.6 1.5180mm 1.9 1.7 1.6200mm 2.0 1.8 1.7225mm 2.1 1.9 1.8250mm 2.2 2.0 1.9280mm 2.3 2.1 2.0315mm 2.5 2.3 2.1355mm 2.6 2.4 2.2400mm 2.8 2.5 2.3450mm 2.9 2.7 2.5500mm 3.1 2.8 2.6560mm 3.3 3.0 2.8630mm 3.5 3.2 2.9710mm 3.4 3.1800mm 3.6 3.3900mm 3.8 3.5

1000mm 4.0 3.7

Note: Figures given are for horizontal support spacings; and may be doubled for verticalsupport spacings.


GPSPOLYETHYLENE

11

Material and SDR Compatibility Summary

(a) Dissimilar materials and dissimilar wall thicknessescan be jointed by electrofusion.

NB. The maximum working pressure should not exceedthe lower value for the two pipes.

See Figure A.

(b) Similar materials and/or wall thicknesses may bejointed by butt-fusion or electrofusion.

NB. SDR17 may be butt-fused to SDR17.6.

See Figure B.

(c) Dissimilar wall thicknesses must not be jointed on-siteusing butt-fusion. NB: PE80 should only be butt-fusedto PE100 (Excel) under closely controlled factoryconditions.

See Figure C.

PE100

SDR17.6 SDR11

CORRECT

PE80

SDR11 to SDR11SDR17.6 to SDR17.6/17

PE100 to PE100PE80 to PE80

CORRECT

SDR17.6 SDR11to

PE100 to PE80

INCORRECT

A

B

C

Organic solvents: petrol and diesel; amylacetate andother esters; acetaldehyde; benzeneand its compounds; carbon disulphide;carbon tetrachloride; chloroform;dichlorethylene; trichlorethylene;ethers and turpenes; coal tar.

Halogens: fluorine; chlorine; bromine in highconcentrations.

Acids: glacial acetic acid; chlorosulphonicacid; cresylic acid; chromic acid; nitricacid (over 25%); phosphoric acid (over50%) and sulphuric acid (over 70%).

Jointing PE to PE by FusionPE pipes of different SDRs

Butt-weldingButt-welding should only be used for jointing pipes of thesame SDR value.

ElectrofusionElectrofusion fittings are able to weld pipes havingdiffering wall thicknesses (SDRs). They are available in achoice of 10bar or 16bar (water) and 5.5bar or 7bar(gas) rating. Care should be taken to ensure that thepressure rating of the fittings is equal to or greater thanthat of the pipe.

SDR applications are marked on individual fittings.However, for the more unusual SDRs, specific adviceshould be sought from our Technical Support Department.

Jointing different types of PEAny medium density PE80 can be joined to any othermedium density PE80 either by butt-welding orelectrofusion. Different pipe producers may havealternative suppliers of preferred PE80 grades, but theseare all intended to be joined by identical techniques.Similarly different grades of PE100 can be joined togetherin like fashion. Butt-welding different pipe materials - forexample, PE80 to PE100 - is not recommended on site(see below).

GPSPOLYETHYLENE


Various ISO/CEN working groups have considered thedesign factors that should be used to determine themaximum operating pressures of polyethylene water andgas systems. These factors will account for any additionalloadings or environmental conditions, eg. elevatedtemperature or exceptionaly poor ground conditions.

The graph below shows the reduction factor which shouldbe applied to the recommended maximum continuousworking pressure at 20ºC to obtain appropriate workingpressures for elevated temperatures.

P R E S S U R E R A T I N G S A N D F L O W C H A R A C T E R I S T I C S

100.4

0.5

0.6

0.7

0.8

0.9

1.0

20 30 40 50 60

Fac

tor

Temperature °C

Reduction factor vs Temperature

Surge and fatigue in PE80 and PE100(Excel) pipesThe two phenomena of surge and fatigue may be treatedseparately, since they describe different potential effects onthe pipe material. UK IGN 4-37-02, March 1999, can besummarised as follows with respect to PE pipe systems:

Surge

For systems where extreme transient conditions are unlikely,it may be safely assumed that the peak surge pressure willnever have a value more than twice the rated steady statepressure. Occasional surge pressures of up to this value willnot harm even low toughness PE pipes that have been ratedfor the steady state system pressure.

Fatigue

Fatigue is associated with repeated transient pressurevariations occurring over an extended period of time. Thefatigue resistance of PE pipes depends on the toughness ofthe material used, as well as on the magnitude of thepressure variations. Data from numerous laboratory andfield test programmes have resulted in the table below (seealso the Notes) which can be used to re-rate PE pipesaccording to material toughness and the predicted frequencyof pressure excursions in the system:The reduction graph has been calculated to give normal

factors of safety after 50 years. It refers only to theconveyance of fluids to which the pipe material iscompletely resistant.

MAXIMUM CONTINUOUS OPERATING PRESSURES AT 20ºC FOR GPS STANDARD PE PIPES.

PIPE OD SDR11 SDR17.6(GAS) / SDR17 SDR21 SDR26SDR17 (WATER)

PE80 PE100 (EXCEL) PE80 PE100 (EXCEL) PE100 (EXCEL) PE100 (EXCEL)GAS WATER GAS WATER GAS WATER WATER WATER WATER

20mm 5.5 12.525mm 5.5 12.532mm 5.5 12.550mm 5.5 12.563mm 5.5 12.5 7.0 16.0 3.0 8.090mm 5.5 12.5 7.0 16.0 3.0 8.0 10.0110mm 12.5 16.0 3.0 8.0 10.0125mm 5.1 12.5 7.0 16.0 3.0 8.0 10.0160mm 5.1 12.5 16.0 3.0 8.0 10.0 8.0 6.0180mm 4.1 12.5 7.0 16.0 3.0 8.0 10.0 8.0 6.0213mm*225mm 12.5 16.0 8.0 10.0 8.0 6.0250mm 4.0 12.5 7.0 16.0 3.0 8.0 10.0 8.0 6.0268mm*280mm 12.5 16.0 8.0 10.0 8.0 6.0315mm 3.4 12.5 7.0 16.0 2.7 8.0 10.0 8.0 6.0355mm 3.1 12.5 7.0 16.0 2.5 8.0 10.0 8.0 6.0400mm 12.5 7.0 16.0 2.3 8.0 10.0 8.0 6.0450mm 12.5 7.0 16.0 2.2 8.0 10.0 8.0 6.0469mm*500mm 12.5 7.0 16.0 2.1 8.0 10.0 8.0 6.0560mm 7.0 16.0 2.0 10.0 8.0 6.0630mm 7.0 16.0 1.8 10.0 8.0 6.0710mm 16.0 10.0 8.0 6.0800mm 10.0 8.0 6.0900mm 10.0 8.0 6.01000mm 10.0 8.0 6.0

- GPS CAN USUALLY OFFER SDRs OTHER THAN THOSE SHOWN IN THE TABLE, E.G. FOR CLOSE FIT LINING APPLICATIONS

- UK GAS OPERATING PRESSURES HAVE HISTORICALLY BEEN LIMITED TO 7 BAR FOR PE100 PIPE - THIS IS THE RESULT OF THE UK RATING SYSTEM FOR CHARGES ON PIPELINES AT HIGHER PRESSURE

- THERE MAY BE A REQUIREMENT TO DE-RATE MITRED BENDS FOR WATER APPLICATIONS - PLEASE CONTACT OUR TECHNICAL SUPPORT DEPARTMENT FOR ADVICE

- PE80 (MDPE) WATER PIPELINES 355MM AND GREATER IN DIAMETER SHOULD BE DERATED IF SIGNIFICANT AMOUNTS OF AIR ARE PRESENT - SEE THE UK WATER INDUSTRY'S IGN 4-32-18 MARCH 2003

- PE80 (MDPE) GAS PIPE PRESSURES MUST BE FURTHER DERATED FOR TEMPERATURES BELOW 0 DEGREES C.

- THE VALUES IN THE ABOVE TABLE DO NOT ADDRESS ANY OTHER SAFETY-RELATED ISSUES ASSOCIATED WITH PIPELINE DESIGN.

* PIPES SPECIFICALLY SIZEDFOR INSERTION LININGAPPLICATIONS


GPSPOLYETHYLENE

13

HighDaily number Low Toughness Toughness GPSof Pressure PE80 & 100 PE80 & 100Transients Re-rating factor Re-rating factor

4 1.1 0.524 1.5 0.548 1.7 0.5

120 2.0 0.5240 2.3 0.5

1200 3.0 0.5

Notes

• The predicted pressure variation range for the systemmust be multiplied by the factors given in the table inorder to establish the pipe PN necessary to avoid therisk of fatigue damage.

• GPS PE80 (MDPE) and PElOO (Excel) pipes are able toresist a wall stress of 4.6Mpa at 80°C for 1,000 hoursin the EN 13479 Notched Pipe Test without any stresscrack growth, and therefore need no re-rating for fatigueirrespective of the frequency of the surge events (asreflected in the final column).

N.B. The pipe PN must always be at least equal to themaximum steady state pressure of the system, and thepipe must be structurally adequate for the given burialconditions.

Example

A PE100 (Excel) system operating at a steady statepressure of 5bar is expected to experience cyclic transientpressure variations between Obar and 16bar 1200 timesper day. From the table, a pipe pressure rating PN of atleast 8bar should be specified [i.e. 16 (=the pressurevariation in bar) X 0.5 (=the re-rating factor)].

Frictional Pressure Loss in Low PressurePolyethylene Gas PipelinesThe flow charts on the following page are based on theLow Pressure Flow Equation derived from the GeneralFlow Equation as referenced in Section 4.5 of theInstitution of Gas Engineers and Managers publication:

Recommendations on Transmission and DistributionPractice - Distribution Mains (IGE/TD/3: Edition 3: 1992)

For Natural Gas assuming:

General Flow Equation Constant (C) = 7.57 x 10-4

Average Compressibility Factor (Zavag) = 1

Specific Gravity (s) = 0.6

Average Gas temperature (Ta) = 15°C

Standard Temperature (Ts) = 15°C

Standard Pressure (Ps) = 1.013.25bar(absolute)

Low Pressure Flow Equation

(P1-P2) = Q2 x 1.841 x 106 x f x L

D5

where P1 = Upstream pressure bar (absolute)

P2 = Downstream pressure bar (absolute)

Q = Gas flow at base conditions m3/hr

D = Internal pipe diameter mm

L = Pipe length m

fspl = Friction factor (spl = smooth pipe law)

assuming Pipe Absolute roughness (k)

for new pipework = 0.003mm

Efficiency factor (e) = 0.97

Friction factor (fspl) = fspl/e2

where 1 = 14.7519 + 3.5657X + 0.0362X2

(fspl)0.5

with X = log1O (Re) - 5

and Re = 25043 x Q (Reynolds Number)D

The above is considered valid for pressures up to 75mbar.

GPSPOLYETHYLENE


100

10

1

0.10.01 0.1 1

SDR11

Pres

sure

Dro

p m

bar/1

000

m

20m

m

25m

m

32m

m

63m

m

90m

m

125m

m

180m

m

250m

m

315m

m

10 100 1000

Demand m / hour3

100

10

1

0.10.01 0.1 1

SDR17.6

Pres

sure

Dro

p m

bar/1

000

m

90m

m

125m

m

180m

m

250m

m

315m

m

10 100 1000

Demand m / hour3

Flow Charts for Low PressurePolyethylene Gas Pipelines


GPSPOLYETHYLENE

15

Pressure Losses and Flows in PolyethyleneWater Pipelines

Flow Calculations for WaterPressure drop due to friction can be determined forpractical purposes using a flow nomogram. The GPSnomogram is based on the Colebrook White formula forwater at 10°C using a hydraulic roughness factor K fornew pipework of 0.003mm.

The pressure drop at a given flow rate can be determinedas follows: 1. Obtain the internal bore diameter of the pipe to be

used by referring to the dimensions tables. 2. Mark this diameter on Scale A. 3. Mark the required flow rate

on Scale B.4. Draw a straight line

connecting the points onScales A and B and extendthe line to cross Scales Cand D.

5. The velocity of flow inmetres per second isdetermined from theintersection with Scale C.

6. The frictional head loss inmetres per 100 metres ofpipe can then be read offScale D.

FittingsThe calculation of pressure dropin fittings is more complex, butcalculations can be made forequivalent lengths of straightpipe using the Formula E = Fxdwhere:

E = equivalent pipe length(metres)

F = fittings constant (Seebelow)

d = fitting internaldiameter (mm)

To calculate the total pressuredrop in the system, theequivalent straight pipe lengthsfor fittings is then added to thetotal straight pipe length toobtain the total drop.

Fittings constantFitting F90° Elbow 0.03045° Elbow 0.01590° Tee – Straight through 0.02090° Tee – Side branch 0.07590° Long Radius Bend (4D) 0.02045° Bend Long Radius Bend 0.010Reducer (d/D= 3/4) 0.007

NOTE: For sizes not covered by the nomogram, please contact Technical Support Department

15

20

30

40

50

60

70

80

90

100

150

200

250

300

350

400

500

25

35

0.01

0.02

0.05

0.1

0.2

0.30.40.5

1

2

345

20

304050

100

200

300400500

1000

2000

300040005000 300

200

100

500004000030000

20000

10000

500040003000

2000

1000

500400300

200

100

504030

20

10

543

2

1

m3/min.

0.05

0.01

0.1

0.15

0.2

0.3

0.4

0.5

1

1.5

2

3

4

5

10

15

20Approx. values only

0.02

0.03

0.04

0.05

0.1

0.2

0.3

0.4

0.5

1

2

3

4

5

10

20

DHydraulic Gradient

m/100m pipe

CFlow Velocity

(m/s)

BFlow Rate

L/sec L/min

AInternal Diameter

(mm)

Diagram for water at 10C

Flow Nomogram

GPSPOLYETHYLENE


Water mainsThe traditional testing procedures used for most pipelinematerials throughout the Water Supply Industry is given in BSI CP 312:Part 3:1973:Section 10.

These procedures, which are generally satisfactory forlinearly elastic materials, are not suitable, withoutmodified analysis procedures, for visco elastic materialssuch as Polyethylene.

Pipe made from such visco elastic exhibit creep andstress relaxation.

When a Polyethylene pipeline is sealed off under a testpressure there will be a reduction in pressure (pressuredecay), EVEN in a leak free system, due to the viscoelastic (creep) response of the material. This pressuredecay is non-linear in an unconstrained pipe.

A pressure test procedure has been developed by WRc toenable interpretation of the effects of creep and stressrelaxation.

For PE pipe systems the test pressures should always bea maximum of 1.5 times the rated pressure of the lowestrated component and/or 20bar maximum if anymechanical fittings are present. With these provisos thetest pressure should be 1.5 times the pipe rated pressurewhen this is up to 10bar, and 1.5 times the meanworking pressure of the system for pipes rated at 12.5bar and above.

Pressure TestOn reaching the test pressure, and satisfying theconditions for minimal air entrapment, the pipeline isisolated and the pressure allowed to decay. The pressureloading time (t1) to achieve test pressure is used as areference. The natural pressure decay readings atpredetermined times (multiples of t1) are recorded.

A correction of t1 is then used to calculate ratios (N), thevalues of which indicated either the soundness of themain or the presence of an unacceptable leak.

As the pressure decay is of exponential form the use oflogarithms is necessary when comparing readings but theuse of a pocket calculator is all that is required for ‘onsite’ calculations.

PE pipes should be tested in reasonable lengthsappropriate to the pipe diameter, pressurising pumpcapacity, and the prevailing site conditions. Pipelineslonger than 1000 metres may require testing in sections.The pipeline should not initially be subjected to anypressure when filling from the mains supply or fromstanding heads, as this may affect the test result.Polyethylene pipelines must not be pressure tested unlessthe wall temperature is kept to below 30°C; this includesopen trench situations. To enable a precise analysis of thepressure test data, pressure transducers with a loggingfacility and display should be used.The detailed procedure is as follows:

Note: this represents a slight modification of theprocedure detailed in the first printing of the WRc Manualfor Polyethylene Pipe Systems for Water Supply – 1986.

Take a first reading of pressure P1 at t1, where t1 is equalto the pressure loading time t

L.

Note t1c

= t1

corrected = t1

+ 0.4tLTake a second reading of pressure P

2, at a decay time of

approximately 7tL

this is time t2.

Note t2c

= t2

corrected = t2

+ 0.4tL

Calculate N1 =log P

1– log P

2

log t2c

– log t1c

Pressure

Time

Typical pressure decay curve for an unrestrained PE pipeline

P R E S S U R E T E S T I N G - W A T E R


GPSPOLYETHYLENE

17

For a sound main this ratio N1 should be:a) 0.08 to 0.10 for pipes without constraint (eg. sliplined

or not backfilled)

b) 0.04 to 0.05 for pipes with compacted backfill.

If the values are significantly less than the minimumidentified, then there is too great a volume of air in thepipework. This air will have to be removed before asatisfactory test can be performed. Experience shows thatretesting can be more difficult to carry out because thepipe has already stretched due to creep from the pressureoriginally applied.

It is therefore of extreme importance to ensure that air isremoved prior to testing.

Take a further reading of pressure P3

at a decay time notless than 15t

L. Let this time be t

3.

Note t3C

= t3

corrected = t3

+ 0.4tL

Calculate N2 =log P

2– log P

3

log t3C

– log t2C

The ratio for N2

should bea) 0.08 to 0.10 for pipes without soil constraint

b) 0.04 to 0.05 for pipes with compacted backfill.

The sensitivity of the test can be increased by extendingthe value of t

3.

If at any stage during this pressure test an unacceptableleak is indicated, it is advisable to check all mechanicalfittings before visually inspecting the welded joints. Anydefect in the installation revealed by the test should, ofcourse, be rectified and the test repeated.

On completion of a test sequence the remaining pressureshould be released slowly until the pipeline is under itspre-test conditions.

In the event of a further test being required on thepipeline, such a test should NOT be attempted beforesufficient time has elapsed for the pipeline to recover fromthe previously imposed conditions. This recovery time willdepend upon individual circumstance but a periodequivalent to 5 times the previous test period may betaken as a guide.

CommissioningThe commissioning of new or repaired supply anddistribution mains is normally carried out in the followingsequence:• Cleaning and/or swabbing of the main• Filling and sterilisation• Flushing and/or neutralisation• Refilling the main• Bacteriological sampling• Acceptance certification• Introduction and/or returning of the main into service

The sequence for PE should include these basicprocedures but may be adapted to meet particularconditions (eg. pre-chlorination of sliplined mains). In allcases the procedures must comply with the requirementof the local Water Undertaking.

Service pipes should be tested with the ferrule connectedto the main but before the cutter taps into the main.After being tested, all service pipes must be subjected toa final disinfection process before being introduced intothe water supply system. Guidance is given in the WaterUK publication, “Principles of water supply hygiene andtechnical guidance notes”. The water utility should beconsulted with regard to their disinfection policy forservice connections.

Special attention should be paid to the proper sterilisationof those services laid to hospitals and renaldialysismachines.

For further support concerning specific installations,please contact our Technical Support Department.

Pressure testing procedures vary according to utility; it isadvisable that the regulations of the relevant body arereferred to. The following general guidelines are based onthe procedures of the Institute of Gas Engineers.

All new mains and services should be pressure testedbefore being commissioned. This includes any part of thepipeline which has been renewed or altered. It is importantthat the same test instrument is used for initial,intermediate and final pressure readings.

Any pressure testing of a polyethylene pipeline has to allowfor ‘creep’. This is the phenomenon whereby a PE pipe willrelax when pressurised leading to a small increase involume and a decrease in internal pressure.

There are two types of pressure test; hydrostatic andpneumatic. For mains and services which will operateabove 2bar a hydrostatic pressure test should be followedby a pneumatic test, for mains and services with anoperating pressure less than 2bar a pneumatic test onlyshould be sufficient.

Hydrostatic pressure testing

This is carried out before a pneumatic pressure test. Themechanical integrity of a main or service is determined bycompletely filling the pipeline to be tested with waterwhich is then pressurised.

When using this technique the engineer should avoidexcessive test pressures which may occur due tohydrostatic head at low lying points.

An initial test pressure of 350mbar should be applied priorto the main test in order to ensure the general integrity ofthe system.

If the main is being filled by gravity, thought should begiven to the need to vent air at high points and to allowwater removal at low points. Also, excessively aeratedwater should not be used. Wherever possible water shouldbe introduced into the pipeline at the lowest point.

An uninterrupted, even flow of water should be used tocompletely fill the pipe. This should not take place if theair temperature is 2°C or less or likely to drop to such alevel.

Once water has been pumped into the pipe, thetemperature should be allowed to stabilise prior topressurising to the test level (refer to relevant governing

body). This test pressure should be applied to the highestpoint of the pipe and checked with a gauge.

Regular re-pressurisation is necessary before the start ofthe test period in order to permit creep to take place. Oncethis has elapsed the test period can begin.

Pressure and ground temperature should be recorded atregular intervals (e.g. every 15 minutes) during the testperiod.

The pressure test is passed if there is no pressure lossrecorded or if there is a constant or declining pressuredecay rate which does not exceed 5% of the test pressureper hour.

If the results do not meet the above criteria, it is advisableto extend the test period to allow more data to becollected.

Following the test, the water must be removed, usually bythe use of air propelled pigs. Dry pigs should then be putthrough the system until the pipe is deemed dry enough bythe engineer.

Pneumatic pressure testing

This is a leakage test that simulates the system at itsmaximum operating pressure under gas conditions. Whenconducting this type of test account must be taken ofbarometric pressure.

For pipes greater than 63mm stand pipes and gauges,should be connected at the ends of the new main andinclude a pressure relief valve (see figure 1). Air should beintroduced into the main until the correct test pressure isattained.

GPSPOLYETHYLENE


P R E S S U R E T E S T I N G - G A S

Before the start of the test period, the temperature of theair should be allowed to stabilise.

At the start of the test period a pressure reading shouldbe taken followed by another reading at the end. If theperiod is long, it may be wise to take several readingsduring the test. In this way, any early indication ofprobable test failure avoids the need to run for the fullperiod.

When completed, air should be vented in a controlledmanner until the main is at atmospheric pressure.

For pipes of a diameter not greater than 63mm, and oflow pressure (not greater than 75 mbar), air is introducedinto the service through the meter control valve, which isleft open whilst the opposite end of the service, at theelectrofusion tapping tee, is securely blanked off. Formedium pressure (greater than 75 mbar not greater than2bar) and intermediate pressure (greater than 2 bar, butnot greater than 7bar) the test is from the main to theinlet valve of the service governor.

The pressure in the service should be increased to therelevant value.

The test period should be as recommended by therelevant governing body. No pressure loss is permissible.

For low pressure services, once a successful test has beencompleted, the meter control valve should be closed, thetest apparatus detached and the integrity of the metercontrol valve tested. The pressure can then be releasedfrom the electrofusion tapping tee end.

Leakage detection

The pipeline should be dosed with a suitable tracingagent (eg. sulphur hexafluoride or ethyl mercaptan –usage instructions must be followed carefully) andpressurised to 350 mbar. The length of the pipe shouldthen be checked using a suitable detection device. Oncethe leak(s) has/have been located, the pipe should berepaired and all pressure tests repeated.

Temperature effects

Pressure changes with temperature and any calculationsmust consider this. To reduce temperature variations asmuch as possible the pipe trench should be backfilled.

Test equipment availability

For further details of pressure testing, please contact the GPS Technical Support Department.


GPSPOLYETHYLENE

19

Figure 1. Pneumatic pressure testing of gas mains

S Q U E E Z E - O F F

The flow of the contents in a polyethylene pipe, where arepair is required remote from valves or where it would betoo expensive to empty the pipe line, can be arrested byusing equipment that squeezes the pipe walls together.This method was developed by the UK Gas Industry inthe early 1980s. GPS can supply clamps suitable forpipes from 16mm to 400mm in diameter. Hydraulic jacksare used to provide the necessary force to compress thepipe wall for sizes 110mm and above. Manual tools areused up to and including 90mm. Built in rotatable ‘checkplates’ protect the pipe from damage from overcompression. These plates can be exchanged to allow thetool to be used with the many sizes of metric andimperial pipe that exist.

The squeeze-off equipment comprises two tangential barsto apply pressure to the outside of the pipe. The bars aremoved together, manually or hydraulically, squeezing thepipe material until a seal is formed where the upper andlower walls meet.

Hydraulic tools have a spring return for the jack andlocking pins to prevent accidental release of pressureduring operation.

Where the pipe wall is compressed the polyethylene pipewill be severely deformed in the regions of maximumcompression. PE100 (Excel) polyethylene material willalso discolour due to stress whitening.

The pipe will eventually regain its original shape after therelease of the squeeze-off but there will be somereduction in pressure bearing properties for diametersabove 125mm. Re-rounding equipment is available and itis recommended not to force the pipe back to a roundshape more quickly than necessary, especially in coldweather.

The following important points must be followed. Furtherdetails are given in DIS 5.3 or the WRc Polyethylene PipeSystems Manual.

• Specifically designed equipment fitted with the correct‘check plates’ should be used to avoid over compressionof the pipe.

• The procedure must not be carried out within 3 pipediameters of a fitting, a fusion joint or a previoussqueeze-off operation.

• The squeeze-off procedure should not normally be usedon pipes larger than 500mm diameter.

After the squeeze-off procedure is complete the pipe mustbe

• Inspected and re-rounded if necessary

• Renewed if there are any signs that the pipe isdamaged ie splitting or cracking

• Recorded and marked as having been squeezed-off.

Tests which have been carried out by external testlaboratories have indicated that satisfactory long-termperformance can be achieved on previously squeezed-offand re-rounded pipes of various wall thicknesses.

N.B. Individual Gas Companies may limit the maximumdiameter of pipe that can be squeezed-off and/or mayrequire the use of stainless steel reinforcement bandsabove certain diameters.

Operating procedure for 63mm-180mmhydraulic squeeze-off tools1. Screw upwards the two ‘stop screws’ to allow

clearance for the ‘squeeze bars’ to be separated.

2. Using the ‘jacking handle’ turn the ‘oil valve’ on thehydraulic jack in an anticlockwise direction. This willrelease the oil pressure in the jack and allow the twolong return springs to pull up the upper squeeze barand cause the jack to compress within itself.(Occasional assistance by hand may be needed).

3. Check pipe diameter and SDR ratio.

4. Set the ‘limit plates’ on the sides of the squeeze off tothe appropriate size. (The correct size must bepointing downwards towards the lower squeeze bar).

5. Put the squeeze-off on the pipe to be squeezed (itmay be easier to remove the bottom squeeze bar).

6. Using the jacking handle, tighten clockwise the oilvalve on the hydraulic jack (to allow it to be jackedup).

7. Using the jacking bar in the hydraulic jack actuatinglever, pump up the jack and start to squeeze the pipetogether.

8. Continue jacking until the ‘limit plates’ just touch thebottom bar (they should still be moveable by hand).

9. The pipe is now in a 'squeezed-off' condition.

10. If the squeeze-off is to be left in this ‘squeezed-off’condition for a while (for example overnight) it isprudent to tighten down the two safety ‘stop screws’to alleviate any potential hydraulic pressure loss dueto a leak somewhere.

GPSPOLYETHYLENE


H E A L T H A N D S A F E T Y

Our polyethylene products have been installed andused safely in large volumes over many years.However, good working practice is vital in ensuringsafety; our products should be handled andprocessed in accordance with the British PlasticsFederation guidelines. All PE80 and PE100 (Excel)pipe systems contain trace quantities of processresidues and may also contain other materials suchas pigments, antioxidants and UV stabilisers.

Chemically unreactive, PE is regarded as beingbiologically inert, though some pipe materialscontain low levels of additives which may be toxic.

IngestionIngestion of PE should be avoided. Some pipe materialsmay contain additives which are harmful if swallowed.Materials specified for purposes other than carrying watermay contain pigments which are not suitable for use withpotable water. These materials may be hazardous if ingested in largequantities.

InhalationPE does not release harmful fumes at ambienttemperature. The threshold limit value for PE dust is 10mg/m

3(8-hour-

time-weighted average in the working environment), butthe generation of such levels when working with PE pipeand/or fittings is extremely unlikely.

Physical contactPE is not considered to be a skin irritant. Where PE dustis generated by cutting or machining pipe or fittings,powder particles of PE dust may cause eye irritation byabrasion.

Fire characteristicsWhen PE is heated in air, melting will occur at 120-135°C and decomposition will commence atapproximately 300°C. Above this temperature PE willpyrolise oxidatively to produce carbon dioxide, carbonmonoxide, water and various hydrocarbons. These gasesmay ignite and provide heat which may accelerate thepyrolysis of more PE in the vicinity. In burning, moltendroplets of material may be released which could igniteadjacent inflammable materials. Actual cooling conditionsin a real fire will be influenced by many factors such aslocation and oxygen availability, which will determine theprogress and combustion products of the fire.

Combustion of PE may release toxic materials. Avoidinhalation of smoke or fumes. Also, do not allow PE dustto accumulate, since there may be a risk in exceptionalcircumstances of dust explosion, and consider carefullythe sitting of potential heat sources such as electricalequipment.

In case of fire with PE80 or PE100 (Excel), any fireextinguisher may be used. Powder extinguishers are veryeffective in quenching flames. Water sprays are especiallyeffective in rapid cooling and damping down a fire, butare not recommended in the early stages of a fire sincethey may help to spread the flames.

Other factors will also influence the selection of fireextinguishers eg. proximity of live electrical equipment.

Handling of molten materialDuring the fusion welding of PE pipe and fittings moltenPE is formed which, if allowed to contact the skin, willadhere strongly and cause severe burns. Such moltenmaterial has a high heat content and will remain hot forsome time. Gloves should be worn where there is any riskof skin contact.

Small quantities of fumes may be given off by molten PE– these are more pronounced at higher temperatures andgreater care must be taken where there is a risk of PEadhering to heated surfaces, such as heating plates usedfor welding. Ventilation must be provided to ensure safeworking conditions.


GPSPOLYETHYLENE

21

Allow for a certain amount of deflection or slight bendingof pipe bundles when loading or unloading. Standard sixmetre bundles may be handled by forklift, but longerlengths should be moved by a side-loader with aminimum of four supporting forks or by a crane with a spreader beam. Individual lengths should be handledsimilarly. Off-loading on site will be eased by skid timbersand rope slings.

Coils Small coils of pipe strapped on to pallets are easilyhandled by forklift. Larger coils of 125mm or 180mmpipe will require lifting individually by forklift.

Releasing coils Safety first: Pipe held in coils is under tension and isstrapped accordingly. Coils may be hazardous if releasedin the incorrect manner – particularly if the end of thepipe is not kept restrained at all times. It is mostimportant to read and understand the following guidelinesbefore attempting to release coils.

GPSPOLYETHYLENE


H A N D L I N G & S T O R A G E

Slings Support timbers

12 metre pipe bundle

Good lifting practice

Handling of long lengths

General Handling

Polyethylene is a resilient material, lightweight andeasy to handle. Nonetheless, care should be takennot to cause excessive scuffing or gouging of thesurface. In addition to the guidelines set out here,the handling and storage of PE pipe is covered bycodes of practice issued by various utilities (eg. theWRc manual for PE pipe systems for water supply& IGE/TD/5:1992).

In lifting operations, where either manual ormechanical effort is involved in moving a load, thefollowing points are common to all situations andprovide the basis on which the selection of theappropriate type of lifting equipment can be made:

• The weight of the load• The bulk, size or shape of the load• The method of joining the load to the lifting

system• The centre of gravity of the load• The method of security or stabilising the lifting

equipment

Plus the training of personnel involved in liftingoperations

Loading and off-loadingLengths and bundles A flat-bed vehicle, free from sharp objects and projectionsshould be used for transporting pipes. When lifting pipebundles by crane, wideband slings should be used; do notuse chains, hooks or hawsers. For lengths greater than sixmetres, load-spreading beams should be inserted at equaldistances apart.

22

Coils are secured by one of two methods depending onthe pipe’s diameter:

1. Outer bands with additional strapping of individuallayers.Do not remove any of these bands until pipe isrequired for use. Remove them carefully, from theoutermost layer first, so that only the length of pipeneeded immediately is released. Successive layers canbe released by removing banding as the pipe is drawnaway from the coil. Coils of pipe above 32mmdiameter should only be dispensed in the field fromproprietary trailers.

2. Wrapped coils of pipe of 32mm and below haveexternal layers of filmwrap, enabling the free end of thepipe to be taken from inside the coil. Take onlysufficient pipe for immediate use from the coil and onno account remove the outer wrapping until the coil isalmost fully unwound.

Drums Drums are delivered direct to site on a low loader and thepipe is usually dispensed from the drum by pulling offwith a machine such as a JCB. The inner end of the pipeis restrained at the hub of the drum, and althoughdrummed pipe has less energy locked into it than coils,caution is required when parting the pipe end from thedrum. For safety, we recommend that the end of the pipeshould be tethered to the dispensing machine when it isunhooked from the drum. This will prevent potentiallydangerous springing.


GPSPOLYETHYLENE

Recommended practice for off-loading drums

Recommended practice for releasing coils from filmwrap

SupportBattens

1m Spacing

Ground Level

3m M

axim

um

Storage of bundles

Bundles Bundled packs of pipe should be stored on clear,level ground, with the battens supported from theoutside by timbers or concrete blocks. For safety,bundled packs should not be stacked more thanthree metres high.

Fittings Never use hooks to lift fittings. Make sure that the tineson forklift trucks are adequately covered (eg. by scrap PEpipe offcuts).

StorageBadly stacked pallets, coils or bundles may slip orcollapse, causing injury to personnel or damage to thepipe. Pipe-end caps, intended to prevent ingress ofcontamination, should be kept in place during storage.

Lengths Pipe lengths stored individually should be stacked in apyramid not more than one metre high, with the bottomlayer fully restrained by wedges. Where possible, thebottom layer of pipes should be laid on timber battens atone-metre centres. On site, pipes may be laid outindividually in strings. (Where appropriate, protectivebarriers should be placed with adequate warning signsand lamps.)

Pipe Lengths

SupportBattens

1 metre

Lateral restraints

1 m

etre

max

Storage of loose pipes

23

Coils Coiled pipe should be stored flat, especially duringperiods of warm weather, and on firm level ground whichhas suitable protection for the bottom coil. Where spaceis limited and coils are to be stacked, the height ofstacked coils should be such that the stack is stable andthe uppermost coil can be safely handled. Under nocircumstances should the stack exceed 2.5 metres in height.

The use of wooden battens below the bottom coil and asspacers between each layer will facilitate easy access forslinging when the need for transportation to the job isrequired, which should only be carried out by a trainedplant operator.

The eye (loop) on a wire sling can be secured by anumber of methods:- manually spliced, secured by aferrule or secured by a group of bulldog clips.

Manual splicing reduces the SWL of a wire rope to 90%and ferrules to 95%. Bulldog clips reduce the SWL to85% and is therefore not recommended.

A tag should be attached to each wire sling to show anidentifying number and the SWL.

Batches of coils delivered on pallets must remain securedto the pallet and only be broken at the time of use.

For details of safe procedure when releasing coils, seeReleasing Coils under the Loading and off-loading section.

Where large diameter coils are to be stored vertically, coilsmust be secured in purpose built racking and facilities forsafe lifting, movement and loading must be available.

GPSPOLYETHYLENE


2.5

met

res

max

. hei

ght

Storage of coils

Example of racking for vertical storage of large diameter coils

Fittings Electrofusion fittings should be stored under cover in dryconditions, preferably on racking. They should be kept intheir boxes or packaging until ready for use. Butt fusionand spigotted fittings may be stored outdoors, as long asthey are protected against damage and prolonged directsunlight. Electrofusion fittings should be retained in theirplastic bags until used.

Storage outsideBlack polyethylene material contains pigment to provideexcellent protection against degradation due to UVradiation.Blue and yellow polyethylene is UV stabilised to resistdegradations in storage only. The maximum recommendedstorage outside, in Northern Europe, is 12 months.Product stored outside for periods in excess of this shouldbe covered with black polyethylene sheeting or storedunder cover.

The rules on handling and storageNever• Drag or roll individual pipes or bundles.

• Throw/drop pipe/fittings from delivery vehicles.

• Use metal slings, hooks or chains when handling.

• Expose pipe/fittings to prolonged sunlight. (Protect withopaque sheeting or tarpaulin).

• Stack more than three metres or three bundles high.

• Place pipes or fittings in contact with lubricating orhydraulic oils, gasoline, solvents or other aggressivematerials (see Chemical Resistance in the Health & Safetysection).

Always• Store pipes on flat, firm ground, able to withstand the

weight of pipe/fittings and lifting apparatus.

• Keep pipe/fittings well away from sharp objects, suchas flints.

• Use wide non-metallic slings (eg. nylon orpolypropylene).

• Exercise special care when handling pipes in wet orfrosty conditions, since they may become slippery.

• Keep protective packaging (battens, shrinkwrap, pallets,strapping, etc.) intact until pipes/fittings are required foruse.

• Keep pipes/fittings away from intense heat, exceptwhen jointing.

• Allow for some bending deflection when pipes areloaded and unloaded. Lifting points should be evenlyspaced.

24


GPSPOLYETHYLENE

P R O C E D U R E S & T E C H N I Q U E S F O R P I P E L I N E I N S T A L L A T I O N

Polyethylene pipe systems from GPS are designedto make installation quicker, easier and more cost-effective. Installation is as much a part of thecosting equation as ease of maintenance and thecost of the pipe system itself. PE's great advantagein installation is its lightness and flexibility,coupled with its durability and totally securejointing methods. For all modern pipelayingtechniques, whether in rehabilitation work or theconstruction of new pipelines above or belowground level, PE80 (MDPE) and PE100 (Excel)systems from GPS usually provide the simplest,most economic solution. Indeed, rehabilitationtechniques have been developed which relycompletely on polyethylene's unique properties.

A major advantage of PE is that pipe lengths can be butt-fused or electrofusion jointed to form a continuous stringof pipe and there is rarely need for thrust blocks. This,together with the material's inherent flexibility, (seematerial properties section for bend radii) makespolyethylene ideally suited to a full range of new andinnovative installation techniques. GPS PE systemssupport all methods of installation used today includingchain trenching, moleploughing, size-for-size moling, pipebursting and slip-lining. Working practice and techniquesfor installing GPS products by a variety of pipelayingmethods are described below.

Conventionally Buried PipelinesConsiderable savings in the costs of imported backfill(where necessary, see below) reinstatement and wastespoil disposal can be made if trench width is minimised.The dimensions of a trenchline opening are normallygoverned by the pipe diameter, method of jointing andsite conditions. Normal minimum depth of cover formains should be 900mm from ground level to the crownof the pipe. Trench width should not normally be lessthan the outside diameter of the pipe plus 250mm toallow for adequate compaction of sidefill unlessspecialised narrow trenching techniques are used and/orspecially free flowing and self-compacting side materialsare employed (see below).

100mm minimum cover above pipe crown

Compact in layers of 250mm (max.)

Normally 900mmminimum backfill

250mm minimuminitial backfill.Do not use heavy compactionequipment

Fill material toconform toIGN 4-08-01WIS 4-08-02

110mm minimum bedding

25

GPSPOLYETHYLENE


In many instances it may be acceptable to lay PE pipedirectly on the bottom of the trench - especially where thesoil is uniform, and there are no large flints, stones, orother large hard objects present. In rocky ground, thetrench should be cut to a depth which will allow for thenecessary thickness of selected bedding material belowthe bottom of the pipe. Where the finished top surfacewill subsequently be trafficked, and spoil from theexcavation is unlikely to give the degree of ground stabilityrequired, even after a degree of grading and compaction,granular material should be imported. Gravel or brokenstone graded between 5 & 10mm in size provides suitablebedding, since it needs little compaction. Coarse sand, asand and gravel mix, or gravel smaller than 20mm arealso all acceptable straight from the quarry. The bestgranular material available from most modern quarries isdesignated 803X, and has been tested and approved byWRc. This has a maximum particle size of 12mm andvery few fines and allows for trench widths only 50-100mm greater than the pipe irrespective of the

26

excavation method. After lowering the pipe into position,the trench can be backfilled and the layers consolidated.It is important to emphasise that the above requirementsgenerally only apply when the PE pipe is buried in groundthat will subsequently be trafficked, with or without a roadpavement. The stated sidefill and backfill materials arerequired to give a stable top surface - the PE pipe itself willnot be harmed if laid in much poorer surround providedthere are no large sharp stones pressing against it.

Normal sidefill & backfill requirementsFor minor roads excavated material can often be returnedto the trench and compacted in layer thicknesses specifiedby the Utility Company. Relevant Water Industryspecifications. e.g. WIS 4-08-02, permit much coarsermaterial for the side and backfill (uti 10% of pipe nominalsize) for PE pipelines than is recommended for thebedding. However, heavy compaction equipment should notbe used until the fill over the crown of the pipe is at least300mm.

When GPS PE pipes are laid in fields it is preferable andmost cost effective to use the originally excavated materialall around the pipe provided that there are no large sharpstones positioned underneath it (see above). Large claymasses should be kept as dry as possible after excavationand broken up by rotovating. By using as-dug the drainagecharacteristics of the land are not altered, and any slightfuture soil movement as the ground re-stabilises is easilyaccommodated by the flexible and ductile nature of the PEpipes. It can rarely be justified to import granular fill insuch cases and there are no particular benefits from usinga geotextile wrap around the fill area.


GPSPOLYETHYLENE

Low-Dig and No Dig New Lay Techniquesfor Buried Pipelines

Narrow/chain trenchingAs previously noted, a major installation advantage of PEpipe is that lengths can be fused together by butt-weldingto form continuous strings. Since the need for trenchjointing is virtually eliminated, the width of excavationscan be minimised, resulting in reduced labour cost, lessimported backfill and lower reinstatement costs. Modifiedmechanical diggers with narrow buckets are idealprovided that the soil produced by the digging action isrelatively fine. Chain excavators in particular will break upthe original ground finely and permit trench widths only50 to 100mm greater than the PE pipe outside diameter.

MoleploughingThis technique was originally developed for laying landdrainage and adapted for installation of gas and waterpipes in rural areas. It enables pipelines to be laid acrossrural landscapes with minimum disruption to agriculture,while the ground can also be reinstated virtually to primecondition. A new PE pipe string is literally ploughed intothe ground to a prescribed depth and the ground restoredimmediately to its original condition.

Narrow/chain trenching

Moleploughing

Impact molingImpact moling is highly economic in instances such asroad crossings, where considerable savings can be madeover traditional open-cut excavation methods. Trafficcontrol systems are often unnecessary, for example, andthe cost of excavation, backfill and reinstatement isvirtually eliminated. With this installation method,excavation is only necessary at the starting and finishinglocations of the pipeline - in order to accommodate themole and its ancillary equipment. The impact mole drivesa borehole between launch and reception pits, leaving theground surface undisturbed. A sacrificial liner issometimes attached to the mole and pulled along behindit. The PE pipe is pulled directly behind the mole or intothe pre-liner if present. Independent studies haveindicated that only thin walled pipes e.g. thinner thanSDR17, are at significant risk from excessive scoringduring impact moling. However, for total security GPS'sSecura-Line can be specified (see also pipe burstingbelow).

Sacrificial Liner

Impact moling (not to scale)

27

Directional drillingThis is a pipe installation technique that was originallydeveloped for oil and gas wells, however it is nowincreasingly used for PE pipe. It allows pipelines to beinstalled under roads and rivers etc. with minimalexcavation work. Basically, it involves drilling a hole underan obstacle and then pulling the pipeline back through anenlarged hole from the far side.

The stages are as follows:i) A small diameter 'pilot hole' is drilled from one side of

the obstacle to the next by a drill head attached to the'pilot string' which, in turn, may be connected to a'washover' pipe which overdrills the hole and providesrigidity to the pilot string.

WashoverPipe Drill Pipe

Drill Bit

Drilling Rig

Pipeline

BarrelReamer

WashoverPipe

Drilling Rig

SwivelJoint

Pipeline

BarrelReamer

WashoverPipe

Drilling Rig

ii) An enlarged hole is bored by one of various means,which include high - pressure fluid jets for cutting (pluscarbide cutting blades to cope with the more difficultsoils), and drill bits which are driven by mud motors.

iii) The drill head is steered by using a flexible joint closeto the head which is moved by manipulation of thejets or by thrust force on the end of the drill string. Atransmitter in the head sends signals to the surface,and these are received by a hand-held locator whichdisplays both the lateral position and depth of thehead, allowing tracing and guidance of the drill head.

iv) When the drill head exits on the far side of theobstacle, the drill head is removed and a reverse barrelreamer is attached to the washover pipe followed bythe PE pipe string. The reamer is used to increase thesize of the hole to the final size required to enable thePE pipe string to be pulled back through.

In the case of large diameter pipes, a number of passesare made using reamers of progressively increasing sizesbefore the final pull-through of the PE pipe string iscarried out.

GPSPOLYETHYLENE


Rehabilitation and Renovation using No-Dig TechniquesSlip-liningIn slip-lining a replacement PE pipe string of smaller sizeis inserted into an existing decommissioned pipeline.Although rarely necessary, pressure grouting (see nextcolumn) of the annular gap can enable the existingpipeline to be rehabilitated structurally, whilst alsoreinforcing the hoop strength of the new PE pipe.

Though some reduction in flow capacity is inevitable, thiscan be minimised by careful preparation and cleaning ofthe old pipe so that the largest possible diameter of newPE pipe can be inserted. In many instances an averageannular clearance of as little as five per cent of mainsdiameter - less still for sizes above 300mm - has provenadequate where pipelines are reasonably straight and ofuniform bore. In pressure pipelines the reduction incarrying capacity can also be compensated for by anincrease in internal pressure. In gravity applications anyeffect of bore reduction is minimised both by theexclusion of ground water entering the system and by theimproved flow characteristics of PE.

In average conditions welded strings up to 700 metreslong for PE80 and 1000 metres for PE100 (Excel) - canbe pulled into place, irrespective of diameter or SDR andwithout excessive axial strain. The maximumrecommended pulling loads at 20°C for various sizes ofGPS PE80 and PE100 (Excel) pipe are shown on page30.

For long strings we recommend a pipe relaxation period ofat least 24 hours before grouting or making permanenttie-in joints and lateral connections. To further minimiseresidual tensile stresses it is also desirable to carefullynudge in any accessible exposed pipe ends using a diggerbucket. This is especially helpful in warmer weather.

Deformation 0% 1% 3% 6%SDR Permissible External Pressure (kN/m2)33 13 12 10 726 27 25 20 1517 96 88 73 5911 417 383 317 242

© Copyright Water Research Centre 1986

Permissible external pressures on PE pipes at grout curingtemperatures.

Grouting Where ground water loads are an issue in conventionalslip-lining, annular grouting is usually more economicalthan using the heaviest possible grade of PE pipeguaranteed to give satisfactory resistance to ground waterloads. The resistance of the inserted pipe to groutingpressure will depend on SDR and on cross-sectionalcircularity - a particularly important consideration for pipetaken off a coil or drum.

Grouting is irrelevant to close-fit lining systems of course(see below), since the final annular gaps are negligible.The following table is reproduced from the WRc SewerageRehabilitation Manual, Vol III.

Slip-lining (not to scale)


GPSPOLYETHYLENE

29

GPSPOLYETHYLENE


Pipe burstingSize-for-size replacement, or upsizing, of existing ironpipelines can be achieved with significant savings by thepipe bursting method. With this technique an existingmain is cracked open and the borehole simultaneouslyexpanded by a mole. Modern pipe bursting moles -especially those with hydraulically expanding segments -can crack and open out an unserviceable pipeline, even ifit has repair collars or concrete surrounds. Risk ofdamage to adjacent utility installations is minimised byusing hydraulic moles, helping to maximise the costadvantages of using the existing 'hole in the ground'. Upuntil recently, the usual practice was to use a sacrificialpolyethylene sleeve which was drawn behind the molethrough the cleared borehole and the new PE main couldthen be inserted. Naturally the use of a sacrificial PEsleeve or liner increased both time and cost of theoperation, so GPS developed Secura-Line which is anormal PE pipe with an abrasion resistant outer coating.This saves on time because no second insertion has totake place.

30

Maximum pulling loads at 20°C

Nominal PE80 PE100 (Excel)PE Pipe Dia 20ºC load 20ºC load

(mm) SDR Max OD (tonnes) (tonnes)

20 8.7 20.3 0.10 N/A25 11 25.3 0.13 N/A32 11 32.3 0.21 N/A50 11 50.4 0.5 N/A63 11 63.4 0.8 N/A90 17 90.6 1.1 1.490 11 90.6 1.7 2.1110 26 110.6 1.1 1.4110 17 110.6 1.7 2.1110 11 110.6 2.5 3.1125 26 125.6 1.5 1.8125 17 125.6 2.2 2.7125 11 125.6 3.2 4.1160 26 161.0 2.4 3.0160 17 161.0 3.6 4.5160 11 161.0 5.3 6.6180 26 181.2 3.0 3.8180 17 1812 4.5 5.6180 11 181.2 6.7 8.4225 26 226.4 4.7 5.9225 17 226.4 7.0 8.8225 11 226.4 11 13250 26 251.5 5.8 7.3250 17 251.5 8.7 11250 11 251.5 13 16315 26 316.8 9 12315 17 316.8 14 17315 11 316.8 21 26355 26 357.1 12 15355 17 357.1 18 22355 11 357.1 26 33400 26 402.3 15 19400 17 402.3 22 28400 11 402.3 33 42450 26 452.6 19 24450 17 452.6 28 35450 11 452.6 42 53500 26 502.9 23 29500 17 502.9 35 43500 11 502.9 52 65560 26 563.2 29 36560 17 563.2 44 55560 11 563.2 65 81630 26 633.7 37 46630 17 633.7 55 69630 11 633.7 82 103710 26 714.0 47 59710 17 714.0 70 88800 26 804.6 59 74800 17 804.6 89 111900 26 905.0 75 94900 17 905.0 113 1411000 26 1005.0 93 1161000 17 1005.0 139 174

OD = Outside DiameterSDR = Standard Dimensional Ratio

Close-fit insertion systemsClose-fit systems offer two major advantages. They neverrequire grouting (see above) and, in most cases, eventhough there is a slight reduction in pipe diameter, theexceptional hydraulic smoothness of GPS pipe actuallyenables flow capacity to be increased. The followingfigure illustrates the point graphically. Quite clearly,PE100 (Excel) pipe is the best choice where maximumflow capacity is required for a given pressure rating.

If the old main is structurally unsound, close-fit PE liningscan be SDR17/17.6 or SDR11, depending on groundcover and pressure requirements. For pipelines that arestrong but leaking, PE lining thickness down to SDR33 orless should be considered. With a 50-year minimum lifeand exceptional gap-bridging performance, thin-walled PElinings provide a cost-effective sealing membrane that istotally reliable.

Rolldown™One of the first close-fit methods to be developed, wasconceived and patented by the former Stewarts andLloyds Plastics and is now operated by Subterra Ltd. Inthis system pre-welded strings of PE pipe are reduced indiameter by approximately ten per cent - with very littleextension - by pushing them through rollers. The reduceddiameter pipe string is then inserted, often as a separateoperation, into the old pipeline and re-expanded by waterpressure to take up a close fit.

Pipe bursting (not to scale)


GPSPOLYETHYLENE

Flow capacity improvements for close-fit PE80 or PE100 (Excel)lined mains, irrespective of head loss or mains size. (AssumesHazen Williams Roughness Coefficient 'C' of Lining = 150 and1% fit deficit)

–40

–30

–20

–10

0

10

80 100

130 140

1117.626

3342

20

30

40

50

60

70

90 110 120

Lining SDR

Hazen Williams RoughnessCoefficient of Original Mains

Flo

w Im

prov

emen

t (%

)

31

Swagelining™Works by pulling a pre-welded string through a reducingdie and into the old pipeline in one operation. Re-expansion to a close-fit diameter occurs naturally within afew hours of the winching load being released.

External loading If a pipeline to be rehabilitated by any of the abovemethods is deeply buried or passes under a river, thebuckling loads produced by external ground water shouldbe considered. Account should also be taken of PE ovalityand whether grouting will be carried out. Long term safeexternal heads can vary between approximately 60 metresof water for a grouted installation using fully circularSDR11 PE80 pipe, down to about two metres for anungrouted and loose SDR26 lining with six per centovality. These examples assume that the old mains isstructurally sound and that the PE lining OD issignificantly less than the mains bore. If host pipestrength is doubtful, ground and water calculations musttake into account probable soil support and grout stiffness(if used) and the known condition of the existing main.

Embankment installationWhere pipes are to be installed above existing groundlevel and then covered, they should not be laid until themound of made up ground has been built up andcompacted to one metre above where the crown of thepipe is to be. A trench should then be cut into the moundand the pipes laid in the conventional way.

Above-ground supported installationFor exposed supported above ground pipework properanchorage is essential. The structure and anchoragesmust resist or accommodate thermal stresses ormovement over the ambient temperature range to whichthe pipe system will be subjected. Above-ground PEsystems should preferably be installed at or nearmaximum operating temperature. In this way the pipe willbe thermally expanded when clamps or supports arebolted into position (see page 9 for support spacings).Tensile stresses will develop as the pipeline cools, but anysagging will be minimised when it returns to installationtemperature.

SublineAlso developed in conjunction with Subterra, in thistechnique welded up strings of liner pipe ranging indiameter from 8inch right up to 40inch, are deformed inthe field into a "C" cross sectional shape by jacking themthrough a mechanical plough and trough. The C shape isretained by friction-welded plastic straps until these areintentionally snapped by internal water pressure after theSubline string has been winched into the old mains. Theliner SDR is generally chosen to ensure that the revertedliner is pushed out into a tight fit against the host bore bythe normal operational pressure of the mains.

Sleeved SubcoilGPS uniquely manufactures and supplies this product toSubterra and its licensees at 3, 4, 5 and 6inch mainsapplication sizes. Liner pipes at SDR26 and thinner arefactory deformed into a C shape, held by means of a thinexternally applied PE sleeve, and then wound ontocompact drums in lengths of up to more than1,000metres. The sleeve provides for reliable long termshape retention, and also protects the liner pipe when it ispulled off the drum and into a deficient mains. As for itsbigger brother Subline, the Sleeved Subcoil liner pipe SDRis chosen to render a tight fit in the host pipe when thesleeve is intentionally split by installation or operationalpressure. Also in common with Subline, the very compactC shape of Subcoil allows it to negotiate significant bendsin the host mains.

During Insertion After insertion

GPSPOLYETHYLENE


E L E C T R O F U S I O N J O I N T I N G P R I N C I P L E S

The DuraFuse system comprises a complete rangeof PE electrofusion fittings (couplers, elbows, tees,tapping tees and branching saddles) for use withPE long spigot fittings and pipe in either PE80(MDPE) or PE100 (see material compatibilitysection).

Electrofusion PrinciplesHot and cold zones, sometimes called melt and freezezones, are formed after energising the coil. The length ofthese zones is particularly important. Each zone ensuresthat fusion is controlled to a precise length of the socketof the fitting and that the melt pressure is also controlledthroughout the entire jointing process. The preciselycontrolled pitch and positioning of the coil in relation tothe inner surface of the socket ensures uniform heatdistribution. DuraFuse electrofusion fittings are suppliedfor mainly 39.5V operation although some sizes andmaterials are available for 79V operation.

HotCold Cold ColdHot

DuraFuse Technology andProduct DesignAll DuraFuse electrofusion fittings employ the samebasic principle. The socket of the fitting incorporatesan electrical heating coil. An electrofusion control unit(ECU) supplies the electrical energy necessary to heatthe coil. When the coil is energised the materialadjacent to it melts and forms an expanding poolwhich comes into contact with the surface of the pipe.The continued introduction of heat energy causes thepipe surface also to melt and a mixing of pipe meltand fitting melt takes place; this is vital to produce agood weld. Following the termination of the heatcycle, the fitting and pipe are left to cool and themelted material solidifies to form a sound joint. Highintegrity, consistently reproducible electrofusion jointswill only be achieved if the following criteria are met:

• Heating coils are as close to the joint surfaces aspossible.

• Wire position is accurately controlled duringmanufacture and during the subsequent fusionprocess.

• Heat distribution is uniform over the length of thehot zone.

• Melt pressure and temperature are both accuratelycontrolled.

• Coils are protected from damage prior to, during andafter fusion.

The design and unique manufacturing technique of theDuraFuse electrofusion system ensures positivecompliance with all these criteria.

Electrofusion Control UnitsGPS manufactures, under the Calder brand name,electrofusion control units to meet all conceivable needs.In addition, a comprehensive range of accessories is alsooffered.Electrofusion control units are designed to operate froman electrical mains or field generator supply having anoutput of 110V and a rating of generally 3 to 3.5kVA for39.5V fittings and 6 to 7kVA for 79V fittings.Electrofusion control units can also be obtained combinedwith an integral generator.All ECUs manufactured after 1st January 1996 for saleinto Europe comply with the Electro-MagneticCompatibility Directive and are CE marked.All units have been designed for arduous site conditions.They are equipped with combined carrying and protectiveframes.

32


GPSPOLYETHYLENE

Bar Coded Electrofusion FittingsTechnology is now available which eliminates the need toenter the fusion time manually. Special control units canbe supplied with the ability to read a bar code wherefixed to an electrofusion fitting. These machines have a'light pen' attached which the operator uses to input thedata contained within the bar code. Bar code control unitsalso have data logging facilities to ensure traceability ofwelding parameters. An output socket allows thedownloading of this information onto a computer databaseor printer to obtain a complete record of the joints whichhave been made. This information can be downloadeddaily, or upon completion of the project. The units willstore up to 200 operations. The ECU will display adescription of the fitting which includes three digits todenote size and this should be read and checked by theoperator before proceeding.

26 Digit Bar Code Traceability for Spigot FittingsDuraFuse Black PE100 (Excel) and PE80 (MDPE) fittings are fitted with traceability bar codes, these bar codes can be read byany bar code Electrofusion Control Unit fitted with a traceability option. The traceability bar code contains specific informationregarding the manufacture of the product such as: the name of the fitting manufacturer, the type of fitting, the size of thefitting, the production batch number, the manufacturing plant where the product was made, the product SDR rating, theproduct raw material, the material status (virgin etc)., the material MRS PE80/PE100 (Excel) and the material melt flow index.

Temperature/Fusion time compensationDuraFuse products are designed to work on a fixed fusiontime for temperatures between -5ºC and +23ºC. Wherethe time is being entered manually then temperaturecompensation is not normally necessary within theseparameters. The bar code system will automatically adjustthe fusion time by small amounts to compensate forvariations in ambient temperatures. Additional datarelating to extremes of temperature can be obtained fromthe GPS Technical Support Department.

26 Digit Traceability Bar code Identification Black PE fittings only - Example

1 2 3 4 5 6 0 1 7 0 6 0 1 0 2 1 63 4 5 1 0 3 0 6 3

Diameterin mm

Manufacturer(DuraFuse)

Production BatchNumber

GPSSite

CheckDigit

SDR Rating

0 - >SDR 331 - SDR 332 - SDR 263 - SDR 214 - SDR 17.65 - SDR 176 - SDR 13.67 - SDR 118 - SDR 99 - <SDR 9

Melt Flow Rate

1 - <5g/10min2 - 5-7g/10min3 - 7-10g/10min4 - 10-15g/10min5 - 15-20g/10min6 - 20-25g/10min7 - 25-32g/10min8 - 32-40g/10min9 - 40g/10min

PE Compound

0601 - (Autofina)Finathene3802B

0504 - (Solvay)EltexTub 121

Shape Code

01 - Straight Pipe02 - Coiled Pipe03 - Coupler04 - Tapping Saddle05 - Branching Saddle06 - 90º Elbow07 - 45º Elbow08 - Other Elbows09 - Tee10 - Endcap11 - Reducer12 - Swept Bend13 - Stub Flange28 - PE/Brass Transition Fittings29 - Excess Flow Valve

Material Status

0 - Virgin

PE Type

2 - PE803 - PE100

33

GPSPOLYETHYLENE


Electrofusion SequenceThe sectional drawings show the jointing sequence fromenergising the coil until completion of fusion. The wholecycle is electronically monitored by the electrofusioncontrol unit (ECU).

1

Pipe positioned in coupler prior to energising coil.

IndicatorHoles Terminal

Top ofCoupler

Coils

Pipe Pipe

2

Coil energised.

3

Material surrounding coils starts to melt.

4

Area of melt extends leading to expansion towards pipe surface.

5

Heat transfers to pipe wall and pipe material starts to melt.

6 Freeze Freeze

Melt solidifies at the start of the cold zones, thereby sealing the melt zone. Further input of energy causes increase in melt pressure.

7

Melt pressure reaches optimum value at end of energising cycle. Emergence of the melt at the indicator holes shows that fusion is complete.

34


GPSPOLYETHYLENE

Jointing using electrofusion is simple, quick andefficient. Successful joints can be consistentlyreproduced after very simple training. Similarprocedures are used for all electrofusion systemswith respect to preparation and assembly. Somefittings require the fusion time to be entered intothe ECU manually and are therefore described asmanual. Some fittings incorporate auto-recognitionaids and the ECUs are therefore described asautomatic. The majority of fittings require a 39.5Vsupply but some larger couplers are designed toaccept 79V supply.

The instructions that follow describe the DuraFuseelectrofusion fittings used to joint adjacent lengthsof pipe and Long Spigot fittings. Proceduresdescribed must be read in conjunction with anyCode of Practice affecting a particular industry, forexample:

• British Gas Code of Practice and IGE/TD/3

• WIS 4-32-08 Issue 3 April 2002

• WRc Manual for PE pipe systems for watersupply applications, 3rd Edition 2002.

Equipment• Generator (11OV for the UK and 220V for Europe).

Generally 3.5kVA output for 39.5V fittings and 6 to7kVA for 79V fittings.

• Electrofusion control unit (ECU).

• Clamping equipment.

• Pipe scraping preparation tool capable of removing 0.2to 0.4mm from the outer surface of the pipe.

• Ancillary equipment such as marker pen, solvent wipeand clean cloth/paper towel.

• Pipe cutter/saw.

• A shelter to protect the pipe, fittings and ancillaryequipment against adverse weather conditions andcontamination.

D U R A F U S E E L E C T R O F U S I O N J O I N T I N G P R O C E D U R E S

35

Transition FittingsGPS transition fittings, available from 25mm x 3/4" to63mm x 2", are made by anchoring a short polyethylenepup onto a machined brass component. The black PE80spigot is designed to be a light interference fit insideDuraFuse electrofusion fittings. Transition fittings are onlysupplied as electrofusion assemblies.The brass component should be fully tightened, using aspanner, before the fusion cycle is started. PTFE tapeshould be used to seal the threads.It is possible to make minor adjustments to the threadedcomponent after fusion. Adjustment should be restrictedto 1/4 turn as excessive movement may damagecomponent parts within the brass transition.

Recommended Torque Values for Transition Fitting Installation

Fitting Recommended torque (Nm)

25 x 3/4 5032 x 1 60

40 x 11/4 8050 x 11/2 9063 x 11/2 9063 x 2 105

GPSPOLYETHYLENE


Procedure1. Cut the pipe square and remove burrs.

2. Wipe loose dirt from pipe ends.

3. Without removing the protective wrap, place thecentre of the electrofusion fitting alongside the pipeend and mark the pipe around the circumference,approximately 15mm beyond the extremity of thesocket depth, using a felt tip pen.

4. Using the pipe end preparation tool, remove theentire surface of the pipe over the marked area,preferably as a continuous ribbon or strip. Note: Theuse of mechanical end preparation tools is preferredas hand scraping requires great care and can betime-consuming especially on larger diameter pipes.It is essential that material is removed by scraping orpeeling; scratching or abrading is not sufficient.

5. Remove the fitting from its packaging and check thatthe bore of the fitting is clean and dry.

6. For water applications clean the scraped area of thepipes and the fitting surface with Isopropanol wipes.For gas applications, the scraped area of the pipeshould not be wiped. Once wiped or scraped do nottouch the cleaned ends of the pipe or the inside ofthe coupler with your hands or rags.

7. Insert the pipe ends into the fitting so that they are incontact with the centre stop.

8. For all socket electrofusion fittings (couplers,reducers, elbows and tees) clamps must be used.The clamps must be adjusted to suit the particularsize and type of fitting being welded so the pipescannot move during the fusion cycle. If possible,rotate the fitting to check that the pipe ends arecorrectly aligned.

9. Remove the terminal protection caps from theterminal shrouds.

10. Connect the ECU output leads to the fitting terminals.Note: It does not matter which lead is connected toeach terminal. (The connections are not live andneutral).

11. Check that there is sufficient fuel in the generator tocomplete the joint. Start the generator and check forcorrect operation.

12. Operate the ECU according to the instructions, whichshould have been thoroughly read and understoodprior to any welding operations. The ECU will eitherhave some form of automatic operating system orrequire manual operation. Whichever system the ECUuses, all DuraFuse fittings are marked with bothfusion and cool times in seconds plus the necessaryinput voltage.

36


GPSPOLYETHYLENE

13. If the fitting has melt indicators check that they haverisen. The molten material should have risen to apoint just above or just below, the surface of thefitting. (DuraFuse PE100 (Excel) fittings size 63mmand below do not have melt indicators. Couplers355mm and 400mm have heat sensitive labels toindicate that sufficient heat has been generated).

14. The joint must be left in the clamps for the coolingtime specified on the fitting, although the terminalleads may be removed carefully without disturbingthe joint.

If the fusion cycle terminates before completion of thecount-down, check for faults as indicated by the ECUdisplay.Check that there is adequate fuel in the generatorOnce the fault has been rectified the welding process canbe recommenced, but the timer has to be reset to zero.If using a transformed supply, make sure that the supplylead to the ECU is not of excessive length.NEVER extend the length of the leads from the ECU tothe fitting.Do not pressurise the system until the joints have cooledto ambient temperatures.

Electrofusion Jointing of Coiled Pipei) Up to 63mm diameter. Clamps must be used which

align and restrain the pipes.ii) Greater than 63mm diameter. To electrofuse coiled

pipe with a diameter greater than 63mm, the pipemust be rerounded.

RepairThe pipe stops incorporated in the DuraFuse couplers areshearable and have been provided for the specific purposeof using the fittings for making repairs or breaking intoexisting pipelines.

The procedure, shown diagrammatically in fig.1: is asfollows:

1. Cut out the damaged section of pipe and ensure thepipe is cut square.

2. Measure the distance (L) between the exposed pipeends and cut the pipe length to be inserted equal tothe measured distance less 10mm.

3. Clean the pipe ends for a distance slightly greaterthan the overall length of the coupler.

4. Scrape the pipe ends, as previously described, but forthe overall length of the coupler.

5. Remove the pipe stops in the coupler. This can bemost satisfactorily achieved by placing one end of athoroughly cleaned short length of pipe into thecoupler and striking the other end onto a hardsurface. The pipe stops can also be removed using asharp knife, but care must be taken not to damagethe bore of the fitting.

6. Using a felt tip pen, draw a mark on each end of thepipe to be inserted which will be used to indicatewhere the mouth of each socket of the coupler shouldbe positioned prior to fusion.

7. Check the jointing areas are clean and dry, useisopropanol wipes if necessary.

8. Care should be taken to ensure any of the residualwater in the mains is not allowed to come intocontact with the electrofusion area. It may not bepossible to maintain a clean dry area, in such casesthe couplings should be mechanical such asPush-Fast fittings.

9. Place the repair couplers over the exposed length ofthe installed main and slide these away from eachother to allow the new pipe to be inserted betweenthe exposed ends.

10. Insert the new pipe and align.

11. Slide the couplers towards each other as shown inthe diagrams ensuring that the socket mouths line upwith the marks on the pipe.

12. Carry out the normal jointing procedure as describedin the previous section.

Figure 1.

37

GPSPOLYETHYLENE


FRIALEN® 400, 450, 500, 560 and630mm Coupler Installation ProcedureFor site representation or to arrange product installationtraining, please contact our Technical SupportDepartment.

Essential Equipment:

1) 7kVA Minimum petrol generator

2) FRIALEN® electrofusion control box

3) Mechanical pipe scraper FWSG630

4) Re-rounding clamp

5) Alcohol wipes

6) Packing tape

7) Hand scraper

8) Marker pen

9) Rubber/nylon hammer

10) Outside diameter tape

Additional Equipment:

1) Feeler gauge

2) 90º Set square

EQUIPMENT CAN BEHIRED FROM FRIATEC’S(GPS’) APPROVED HIRECENTRES:-

HIRE CENTRE - TEL: 01462 457591

The installation of large diameter electrofusionfittings (400mm and above) is a specialist activity.To ensure full control over the quality ofelectrofusion jointing it is important that thefollowing procedures are adhered to. Largediameter couplers must only be installed bycontractors/operatives who have successfullyachieved the standards required on the GPStraining course. Successful candidates will possessa Frialen ECU operator control card and acompletion certificate.

Friamat Electrofusion Control Units are supplied inthe closed operating mode ensuring that they canonly be activated by the trained operator's controlcard.

J O I N T I N G P R O C E D U R E S F O R F R I A L E N ® L A R G E D I A M E T E RE L E C T R O F U S I O N C O U P L E R S

38


GPSPOLYETHYLENE

FRIALEN® Large Diameter ElectrofusionCouplers Jointing ProcedureElectrofusion Coupler Electrical Check

1. Check that the coupler is OK by running the fusioncycle for 10-12 seconds. Before starting this processstart the generator and leave to settle forapproximately 1 minute. Ensure that the FRIALEN®

ECU is switched OFF before connecting the powersupply lead to the generator, then connect it to thegenerator and switch ON.

2. Before starting it will be necessary to first swipe youruser card I.D. card and log on to the ECU. There aretwo bar code labels on each FRIALEN® fitting. Theremay be two single bar code labels, one white andone yellow, or two white (see below), one with onebar code and one with two bar codes. Connect theleads of the electrofusion control unit to one side ofthe coupler. Once connected swipe the WHITE barcode on the fitting that has a yellow and a white barcode label. Where the fitting has two white bar codelabels swipe the Fusion bar code on the “Double” barcode label (see diagram below) on the fitting andpress START on the ECU. Once 10-12 seconds haveelapsed press the Stop button. (This procedurechecks the heating element).

3. If the coupler cuts out during this 10-12 secondscheck the ECU for error messages and rectifyaccordingly after turning off and disconnecting theECU from the generator. The most probable cause isa faulty generator or dirty connections/terminals.Should the coupler prove to be faulty then mark thecoupler and return to supplier.

Preparing the pipe

1. Check the pipe for any abrasions or impact damagethat may provide a detrimental effect to theperformance of the coupler.

2. Ensure that the pipe end is cut square. It may beuseful to use a setsquare to be certain - the pipeshould not be out of square. Use your outsidediameter tape to measure the pipe dimension. Thepipe diameter should be greater than the nominal(minimum) diameter specified. By determining theoutside diameter of the pipe it will aid you whentrying to access how much of the pipe material needsto be scraped off from the outside diameter of thepipe.

3. The FRIALEN® Mechanical Scraper takes offapproximately 0.25mm of the pipe surface perrotation. Note - this equates to 0.5mm reduction ofthe pipe diameter.

4. Once you have established how much material isrequired to be removed you can now mark the pipeend for the couplers insertion depth.

5. Before scraping takes place clean the surface of thepipe to remove as much grease, oil or surface dirt aspossible.

6. Use your hand scraper to create a chamfer on theleading edge of the pipe and remove all swarf fromthe pipe. This will provide a smooth leading edge toassist with the installation of the coupler.

7. Mark the pipe end for the couplers insertion depth (1⁄2Coupler Iength plus 5mm). Use wavy lines to helpidentify the area that needs to be scraped. If thecoupler is to be used for a repair, the whole length ofthe coupler should be scraped.

8. Check that the scraper blade is in good condition.Worn blades must be replaced. Scrape the surface ofthe pipe to remove any dirt and the oxidised layer therequired number of times, but before the final scrape,try the coupler on the pipe and check the fit andestablish any “pinch points”.

9. Scrape off any remaining line markings using handscrapper (groves and scratches should not be presenton the area to be fused) and then use the alcoholwipes to clean the outside surface of the pipe. Useseparate wipes to clean the inside of the coupler. Alltraces of the cleaner should be allowed to evaporatecompletely prior to the fusion process continuing.

10. DO NOT TOUCH THE CLEANED ENDS OF THEPIPE OR THE INSIDE OF THE COUPLER WITHYOUR HANDS OR RAGS.

11. Protect the end against the ingress of dirt, dust orwater.

39

Training Certificate?

Have you got yours?

Telephone: 01480 442620

GPSPOLYETHYLENE


Final Preparation

1. We have now completed the final preparation beforestarting the fusion process. Fusion should now beconducted immediately after scraping.

2. Measure 1⁄2 coupler length on the end of each of thepipe ends to be joined and using your marker penmark this onto the pipe. Now set the hydraulic

re-rounding clamp to the pipe behind the mark.

3. Place coupler on to the end of the pipe and establishwhere pipe ovality may interfere with placing thecoupler onto the pipe. It may be necessary to markthe pipe end and hand scrape the affected area.

4. Deburr both the inner and outer end edges of thepipe using the hand scraper before proceeding. Youare now ready to install the coupler onto the pipe.Frialen couplers are designed to be an interference fitand it may be necessary to tap the coupler with careonto the pipe using a nylon or rubber mallet. Caremust be taken not to allow the coupler to ‘tilt’ on thepipe during this final phase. Knock the coupler onusing the rerounding clamp as a stop. Note - Themaximum air gap between the pipe and theelectrofusion fitting should be no more than 2mm. Ifin doubt, this should be checked with a feelergauge. Particular care should be taken if a feelergauge is used as these can be a source ofcontamination to the previously cleaned surfaces andcan damage the wires of the electrofusion fitting.

5. Control localised gaps by using packing tape to closethe annual gap between the pipe and coupler, thiswill help keep any warmth inside the coupler, thusaiding the preheat process to close any gaps causedby ovality or pipe tolerances.

6. Before starting the fusion process ensure, that boththe pipe and the coupler are adequately supportedto stop any 'sagging' during the fusion process andavoid any tension on the coupler.

Electrofusion Process

1. Now connect up the Frialen ECU as previouslydescribed. Connect the terminal leads to the couplerand swipe the yellow bar code this initiates thepreheat cycle of the coupler. Confirm the details on theFrialen ECU display and press Start button. Oncecompleted allow the electrofused side to warm (heatsoak) for a minimum of 12 minutes and a maximum of14 minutes, this will allow the pipe enough time toexpand inside the coupler. It may be necessary topreheat more than once. Up to a maximum of threetimes is permissible (depending on wallthickness/SDR).

2. Each preheat cycle should bridge a gap ofapproximately 1mm between the pipe and coupler.

3. Once you are satisfied that you have taken adequateprecaution to eliminate any gaps, you can now proceedwith fusion process. To begin fusion return to the firstside and reconnect leads to the terminal and swipe theWhite Bar Code. Confirm the details press Start oncontrol box display and press Green Start button.

4. Repeat steps 1 to 4 for the other side. Precaution mustbe made to prevent any movement bending or pullingon the coupler to avoid tension on the joint during thefusion cycle.

5. It is also important not to disturb the joint during itsfusion or cooling period.

• Note: Frialen Safety Couplers have fusion indicatorsnext to the terminals, which fill up to the shoulderwhen the fusion process has taken place. One way toobserve this is to insert a match in the indicator holebefore commencing fusion.

Datalogging/Fusion Completion

1 Download joint data from the electrofusion control unitfor trace ability.

2 Swipe l.D card - log off.

Please Note: Additional Points to Remember

1. Handle couplers and fittings with care. Do not dropor throw.

2. Always store in a clean dry place. Never outside.

3. All fittings Must be pre-heated to the mainelectrofusion weld. Take care to adhere to theminimum and maximum times between pre-heatand final electrofusion.

4. Always ensure that the generator has sufficient fueland does not run out during fusion as this couldlead to a failed joint.

5. The weld indicators do not always fully protrudefrom the fitting; this does not indicate a weldfailure.

40


GPSPOLYETHYLENE

Tapping tees - jointing procedure using thestrap type loading tool1. Remove the tapping tee from the polyethylene

wrapping, leaving the cardboard protector in positionsecured by the red terminal protectors.

2. Place the fitting on the mains pipe in the position inwhich it is to be welded, with the cardboard protectorstill in position. Mark the outline of the unit on thepipe using a felt tip pen.

3. Remove the fitting and place somewhere clean anddry. Thoroughly scrape the pipe within the markedarea to completely remove the surface layer.

4. Rotate the handwheel of the top-loading tool until thestop is reached.

5. Remove the threaded cap from the top of the tee andcheck that the cutter head is flush with or slightlyproud of the threaded stack.

6. Remove the red terminal protectors and remove thecardboard protector from the underside of the fitting.

7. Place the fitting on top of the prepared area on themain pipe.

8. Press the nose of the loading tool into the aperture inthe top of the tapping tee cutter and push fully home.

9. Holding the loading tool and the tee in position withone hand, push the straps under the main pipe andup through the slots in the tool. Ensure that thestraps are not twisted or kinked. Clamp the straps inplace using the lever locks. It is not necessary, at thisstage, to pre-tension the straps to a taut condition.

10. Still holding the tool and tee with the one hand,rotate the handwheel of the loading tool in aclockwise direction until the central indicator is flushwith the top face of the handwheel.

The clamping assembly is now at the required loadingpressure for fusion to commence.

The DuraFuse system includes a range of stack-loading/top-loading tapping tees and branching saddles designedto fit pipes with outside diameters up to 400mm. (Seealso Friatec section).

Stack-loading saddlesThese fittings are designed for use with either the straptype, or the pedestal type stack-loading tools. Both toolsperform the same function of clamping the saddle to thepipe with a predetermined force.

Tapping tees can be electrofusion welded to a live main,the specially designed cutter being used to make a hole inthe pipe once the service connection has been made.

J O I N T I N G P R O C E D U R E S F O R D U R A F U S E T A P P I N G T E E S & B R A N C H I N G S A D D L E S

41

GPSPOLYETHYLENE


Tapping tees - jointing procedure whenusing a pedestal type stack loading tool1. Remove the tapping tee from the polyethylene

wrapping, leaving the cardboard protector in positionsecured by the red terminal protectors.

2. Place the fitting on the mains pipe in the position inwhich it is to be welded, with the cardboard protectorstill in position. Mark the outline of the cardboardprotector on the pipe using a felt tip pen.

3. Remove the fitting and place somewhere clean anddry. Thoroughly scrape the pipe within the markedarea to completely remove the surface layer.

4. Release the wing nut on the pedestal stack loadingtool.

5. Remove the red terminal protectors from the tappingtee and remove the cardboard protector.

6. Remove the threaded cap and check that the cutterhead is flush or slightly proud of the threaded stack.

7. Press the nose of the top loading tool into the cutterhead.

8. Place the grooved base plate underneath pipe andlower the tapping tee onto the scraped pipe surface.

9. Tighten the wing nut.

10. Screw the handwheel in a clockwise direction untilthe central indicator is flush with the top face of thespring carrier.

The clamping assembly is now at the required loadingpressure for fusion to commence.

1. Connect the leads from the ECU to the terminals ofthe tapping tee. Start the generator and key in thecorrect fusion time, as shown on the fitting.

2. Check the loading pressure is correct by ensuring thatthe central indicator is still flush with the top face ofthe spring carrier.

3. Press the fusion start button.

4. On completion of the cycle remove the leads andallow the joint to cool for the required time, as shownon the fitting, before removing the tool.

To remove the tool, unscrew the handwheel anti-clockwise until all the pressure is released and withdrawthe tool from the top of the tapping tee.

• Replace the threaded cap ensuring that the 'O' ringseal is in position.

Service connections - tapping tee to service pipeThe service connections between the tapping tee and theservice pipes are made using either service couplers orservice reducers in conjunction with a miniclamp-typepipe clamp.

The procedure for making a service connection is asdescribed for the electrofusion couplers.

Any hydrostatic pressure test should be carried out on theservice pipe before the hole is cut through the wall of themains pipe using the integral cutter.

Service connections - tapping into a water main Tapping into the water main should not be carried outuntil at least 30 minutes have elapsed following the endof the cooling cycle. After this time period the tappingprocedure is as follows:

1. Insert the tapping key into the recess in the top of themetal cutter and turn in a clockwise direction.Continue until the pipe wall is completely cut through(indicated by a reduction in the force necessary toturn the key).

2. Retract the cutter by turning the key in an anti-clockwise direction until the top of the cutter is flushwith the top of the threaded stack, showing that thecutter is clear of the branch.

The coupon of material cut from the pipe wall will beretained in the end of the cutter.

• Check that the 'O' ring seal is in place in the cap andscrew it down hand tight onto the threaded stack ofthe tee.

Note: Thread Followers - The torque may be high whencutting through the wall of large diameter pipes. Threadfollowers are available to enable the load to be spreadover a greater number of threads, minimising the risk ofstripping the moulded threads inside the stack of thetapping tee.

Jointing Procedures for DuraFuseBranching SaddlesThe procedure for branching saddles is very similar to theprocedure previously outlined except that a hole cutterwill be required to cut a hole in the pipe wall prior tofusing on the saddle. It is also necessary to use anadaptor plate to replace the 'nose' of the stack-loadingtools in order to clamp the fitting onto the pipe surfaceduring the fusion cycle.

42


GPSPOLYETHYLENE

Jointing procedure for using DuraFuseUnderclamp Tapping tees

DuraFuse underclamp tapping tees are supplied completewith 2 types of underclamps as shown below.

DuraFuse tapping tees can be electrofusion welded to alive main, the specially designed cutter being used tomake the hole in the pipe once the service has beenconnected and tested.

Installation procedure for Type BUnderclamp Tapping tee

• Remove tapping tee form bag polythene bag wrapping.• Place the fitting on the mains pipe in the position in

which it is to be welded. Mark the outline of the fittingon to the pipe using a felt tip pen

• Remove the fitting and place in a clean, dry place. • Thoroughly scrape the marked area to completely

remove the surface layer.• Place the fitting back on top of the prepared area of the

main pipe.• Place the strap underclamp piece, without screws, onto

one of the tapping tee wings. The strap piece will onlyfit in one particular orientation to ensure the correctloading is applied.

• Thread the strap under the pipe and place the strapunderclamp piece, with screws, onto the tapping teewing at the other side of the tapping tee. Whilst holdingthe tapping tee in position screw the screws up untilthey are fully tightened and the 2 bars of the strapunderclamp piece are pulled together.

• The tapping tee is now at the required pressure forelectrofusion to commence.

Electrofusion procedure.

• Connect the electrofusion control unit (ECU) leads tothe tapping tee. Start the generator and key the correctfusion time into the ECU. The fusion time is mouldedonto the fitting.

• Press the fusion start button• On completion remove the ECU leads and allow the

fitting to cool for the stated time. The cooling time ismoulded onto the fitting.

• The underclamp pieces can be either left in place orremoved.

See page 42 for instructions on tapping into a main orservice pipe.

43

Installation procedure for Type AUnderclamp Tapping tee

• Remove tapping tee form bag polythene bag wrapping.• Place the fitting on the mains pipe in the position in

which it is to be welded. Mark the outline of the fittingon to the pipe using a felt tip pen

• Remove the fitting and place in a clean, dry place. • Thoroughly scrape the marked area to completely

remove the surface layer.• Place the fitting back on top of the prepared area of the

main pipe. Fit the underclamp piece in to place underthe fitting body and push into place whilst holding thefitting from the top. The underclamp piece should befully pushed on to the fitting wings. A mallet should beused to carefully tap the underclamp piece in to place ifit cannot be fully pushed by hand.

• The tapping tee is now at the required pressure forelectrofusion to commence.

Note: The Site Fusion Jointing Specification WIS 4-32-08Issue 3, April 2002 emphasises the importance for thebutt-fusion machine to be able to control properly thereduced secondary ram pressures that are now requiredfor 'dual pressure' butt-fusion jointing.

For SDR11 pipes of sizes 250mm, 280mm and 315mmand for all pipe (SDRs 11, 17, 17.6, 26) of size 355mmand above, i.e. all pipes with a wall thickness greaterthan approximately 20mm, the butt-fusion pressuresshould be reduced to 1/6 of its initial value after 10seconds and therefore fully automatic butt-fusionmachines are preferred.

• For manual machines a data plate, coloured blue forwater and yellow for gas should be permanentlyattached to the machine.

• For automatic machines the jointing data will beprogrammed in accordance to the SDR rating of thepipe and/or fittings to be jointed.

(These conditions are tabulated in the section followingthe description of butt-fusion jointing procedures).

When jointing pipes using butt-fusion techniques, theheater plate temperatures are the same for both PE80and PE100 (Excel) - 225ºC to 240ºC (average in thecase of low ambient temperatures) as given in WIS 4-32-08 Issue 3, April 2002.

A UK water industry guidance note was published byBodycote PDL in February 2003 that allows an extra oneminute soak time for PE100 pipe sizes above 500mmSDR11. This is designed to ensure that fully ductile weldsare always obtained under all field conditions to complywith onerous UK requirements in this respect.

GeneralButt-fusion is a jointing method which allows on-sitejointing of pipes from 90mm to 1000mm. It is athermofusion process which involves the simultaneousheating of the ends of two components which are to bejoined, until a melt state is attained at each contactsurface. The two surfaces are then brought together undercontrolled pressure for a specific fusion/cooling time andhomogeneous fusion takes place.

The resultant joint is fully resistant to end thrust and hasidentical performance under pressure to the pipe.

This method of jointing requires an electrically heatedplate to raise the temperature of the pipe ends to therequired fusion temperature. It is used for both PE80 andPE100 (Excel) grades of material for pipes of size 90mmand above of the same Standard Dimension Ratio (SDR).

Butt-fusion machines are available in manual, semi-automatic and fully automatic configurations. Themachine sizes start at 90mm and can weld up to1000mm OD pipe.

B U T T - F U S I O N J O I N T I N G P R I N C I P L E S

GPSPOLYETHYLENE


The GPS SystemDepending on the design and make, butt-fusion machinesmay or may not be capable of accepting moulded fittings,as manufactured, for direct welding to pipes. GPStherefore offers two ranges of fittings for butt-fusionsystems to provide the greatest flexibility:

Long Spigot fittingsThese unpupped fittings are long enough to be gripped forbutt or electrofusion by most types of machines/clamps.

'Pupped' fittingsPupped fittings are fabricated by butt-fusing, in thefactory, 0.5m lengths of pipe (pups) to each leg of aspigot fitting. The pup can be gripped by clamps of thebutt-fusion machine. The GPS butt-fusion systemcomprises, therefore:

• Straight polyethylene pipe.

• Long Spigot fittings.

• Pupped fittings.

• Accessories.

Equipment• Generator to supply the heater plate, trimmer and

hydraulic pump.

• Butt-fusion machine fitted with the correct size clampshells, trimmer, heater plate, hydraulic pump andtimer.

• Pipe support rollers.

• Welding tent.

• Cleaning material, lint-free cotton cloth or papertowel.

• External/internal debeading tool.

• Bead gauge.

• Digital thermometer with surface probe to checkheater plate.

• Pipe end covers.

• Baseboard.

• Pipe cutters.

• Air temperature thermometer.

• Indelible marker pen.

• Timer.

Jointing Method Pre-welding checks

Before commencing a welding operation check that:

• There is sufficient fuel for the generator to completethe joint and that it is functioning correctly before it isconnected to the machine.

• The trimming tool and hydraulic pump are in workingorder.

• The heater plate is clean and residues from previouswelds have been removed.

• A tent is available to provide shelter during welding.

• The machine is complete and undamaged.

• The pipes and/or fittings to be jointed are of the samesize, SDR and material.

• The operator knows the correct welding parametersfor the machine and pipe being welded.

• The heater plate is at the correct temperature.(Connect the heater plate to the power supply andretain it for at least 20 minutes inside the thermallyinsulated guard).

The heater plate may bewashed when cold at the startof the jointing session, withcopious quantities of cleanwater to remove dirt deposits.Only clean, lint free materialsmay be used to clean theplate. To remove grease andoily films the plate may bewiped with lint free materialdampened by a suitablesolvent, eg. Isopropanol.

Dummy WeldsEven though washing mayremove large deposits of dirt,very fine particles of dust maystill remain on the heaterplate. To remove such dust itis necessary to make a

dummy joint at the start of each jointing session,whenever the plate has been allowed to cool below180°C, or at a change of pipe size. Two dummy jointsmust be made if the pipe size is greater than 180mm.

A dummy joint can be made using pipe off-cuts of thesame size, SDR and material as the pipe being installed.It is not necessary to actually make a joint. The procedurecan be discontinued after the full heat cycle has beencompleted.


GPSPOLYETHYLENE

45

12. 0pen and then close the clamps and note the dragpressure needed to move the pipes together using thehydraulic system. Drag pressure is the minimumgauge pressure required to overcome the slidingfrictional drag on the rams due to the operation of themachine and the weight of the pipes/fittings beingjointed. Note: the drag pressure (in bar) must beassessed accurately prior to making each fusion jointand must be added to the basic ram pressure valuesshown on the machine. (When fully automaticmachines are used this operation will normally becarried out automatically).

13. Remove the heater plate from its protective cover.Check that it is clean and up to temperature.

14. Place the heater plate inthe machine and closethe clamps so that thesurfaces to be joined aretouching the plate. Usingthe hydraulic systemapply the pressurepreviously determined.

15. Maintain the appliedpressure until the pipe orfitting ends begins tomelt and a uniform beadof 2-3mm is formed oneach.

16. After the initial bead up,the pressure in thehydraulic system shouldbe released so that thepressure gauge registersbetween zero and the drag pressure so as to controlthe bead growth during the heat soak time. Checkthat the pipe does not slip in the clamps. The pipe orfitting ends mustmaintain contact withthe heater plates.

17. When the heat soak timeis completed, open theclamps and remove theheater plate ensuringthat the plate does nottouch the meltedsurfaces.

Manual Welding Procedure1. Place the pipes in the clamps with the ends against

the trimming tool and with the pipe markingsaligned.

2. Align and level the components using the supportrollers.

3. Tighten the pipe clamps to grip and re-round thepipes.

4. Cover the free ends of the pipes to prevent cooling ofthe plate by internal draughts.

5. Switch on the trimming tool and bring the clampsslowly together so that the pipe ends are movedagainst the trimming tool until continuous shavingsare cut from each surface.

6. Keep the trimming tool turning whilst separating theclamps to avoid steps on the trimmed surfaces.

7. Remove the trimmingtool taking care not totouch the trimmed ends.

8. Remove loose shavingsfrom the machine andcomponent ends. Do nottouch the preparedsurfaces.

9. Check that both surfacesare completely planed. Ifthey are not then repeatthe trimming process.

10. Bring the clampstogether and check thatthere is no visible gapbetween the trimmedfaces.

11. The maximum permittedoutside diametermismatch is: 1.0mm forpipe sizes 90mm to315mm & 2.0mm forpipe sizes 316mm to800mm. If the mismatchis greater than thesevalues then the pipemust be realigned andre-trimmed.

GPSPOLYETHYLENE


18. Immediately close the clamps (within 8 to 10seconds of removing the plate) and bring the meltedsurfaces together at the previously determinedpressure.

19. Maintain therequired pressurefor the minimumcooling time asindicated in thetable.

20. After this time theassembly can beremoved from themachine butshould not behandled for afurther periodequal to theabove coolingtime.

21. Examine the jointfor cleanlinessand uniformityand check that the bead width is within the specifiedlimits.

22. Remove the external bead and if required the internalbeads using suitable debeading tools.

23. The beads and joint should be numbered/coded usingan indelible marker pen.

24. The beads should be twisted at several positions. Ifthe bead is seen to split at any point then the jointshould be cut out from the pipeline and the jointremade. If a similar defect reoccurs, all furtherjointing must cease until the equipment has beenthoroughly cleaned, examined and new trial jointsmade and shown to be satisfactory.

The rules for butt-fusionNEVER• Attempt to weld together pipes of different SDR (wall

thickness).

• Touch trimmed pipe ends.

• Leave trimming swarf inside pipe or on weldingmachine.

• Allow equipment to get wet or dusty.

• Use non-approved machinery.

• Remove a weld from the machine before cooling timehas elapsed.

• Allow untrained personnel to use welding equipment.

• Cut corners in any part of the welding procedure.

• Weld pipes of different material on-site.

• Use a generator of inadequate capacity.

Machines can be hired from MCA Hire Services (Luton),who can be contacted on telephone 01582 414140.

Training CoursesIt is essential that all installers of polyethylene pipesystems have received thorough training. GPS offers oneday product familiarisation courses which are designed toprovide a basic knowledge of practices and on-sitetraining. Training leading to a NVQ (National VocationalQualification) can be done at a number of institutions.Two organisations that are used by major watercompanies in the UK are Water Training International(WTI) and Whitwell. WTI can be contacted at their headoffice in Hampshire, telephone 01734 813011. Whitwellin Leicestershire, can be contacted on telephone 01780460323.

In addition, GPS offers a specialist training course on theinstallation of FRIALEN® Large Diameter Couplers. Forfurther information, please contact our Technical ServicesDepartment.

Butt-fusion Jointing Parameters for Gas

Single pressure butt-fusion jointing conditions for PE80 - as employed historically by Transco in the UK.

NB. These are being reviewed in 2004.

Initial Heat Heat Max Plate Cooling Time FinalPipe Bead Soak Soak Removal Under Out of Bead WidthSize Size Pressure Time Time Pressure m/c mm

90 2mm 0 bar 90 sec 8 sec 10 min 10 min 8-12125 2mm 0 bar 120 sec 8 sec 10 min 10 min 8-12180 2mm 0 bar 140 sec 8 sec 10 min 10 min 8-12250 3mm 5 bar 180 sec 10 sec 10 min 10 min 12-16315 4mm 5 bar 180 sec 10 sec 15 min 15 min 14-20355 4mm 5 bar 180 sec 10 sec 15 min 15 min 16-22400 4mm 5 bar 180 sec 10 sec 15 min 15 min 16-22


GPSPOLYETHYLENE

47

GPSPOLYETHYLENE


NB All jointing pressures must be calculated by using the effective ram area of the machine in relation to the cross-sectional area of thepipe wall. Effective ram area varies with manufacturer and models. Effective ram area should be marked on each model.

Table 1 Single pressure butt-fusion jointing conditions for PE80 and PE100 (Excel)

Fusion Cooling TypicalInitial Min and Cooling time for final

Wall Bead up bead soak Max plate cooling Cooling time out coiled overallOutside thickness interface size Soak interface removal interface time in of pipe in bead widthdiameter SDR (minimum) stress (approx) time stress time stress clamps clamps clamps min max

mm mm MPa mm seconds MPa seconds MPa minutes minutes minutes mm mm90 26 3.5 0.15 2 95 0 10 0.15 10 5 15 8 1590 17.6 5.1 0.15 2 110 0 10 0.15 10 5 15 8 1590 11 8.2 0.15 2 140 0 10 0.15 10 5 15 9 16

110 26 4.2 0.15 2 100 0 10 0.15 10 5 15 8 15110 17.6 6.3 0.15 2 125 0 10 0.15 10 5 15 9 16110 11 10.0 0.15 2 160 0 10 0.15 10 5 15 10 17125 26 4.8 0.15 2 110 0 10 0.15 10 5 15 8 15125 17.6 7.1 0.15 2 130 0 10 0.15 10 5 15 9 16125 11 11.4 0.15 2 175 0 10 0.15 10 5 15 10 17160 26 6.2 0.15 2 120 0 10 0.15 10 5 15 9 16160 17.6 9.1 0.15 2 150 0 10 0.15 10 5 15 9 16160 11 14.6 0.15 2 205 0 10 0.15 10 5 15 11 18180 26 6.9 0.15 2 130 0 10 0.15 10 5 15 9 16180 17.6 10.2 0.15 2 160 0 10 0.15 10 5 15 10 17180 11 16.4 0.15 2 225 0 10 0.15 10 5 15 11 18225 26 8.6 0.15 2 145 0 10 0.15 10 5 – 9 16225 17.6 12.8 0.15 2 190 0 10 0.15 10 5 – 10 17225 11 20.5 0.15 2 265 0 10 0.15 10 5 – 12 19250 26 9.6 0.15 2 155 0 10 0.15 10 5 – 9 16250 17.6 14.2 0.15 2 200 0 10 0.15 10 5 – 10 17280 26 10.7 0.15 3 170 0 10 0.15 10 5 – 13 22280 17.6 15.9 0.15 3 220 0 10 0.15 10 5 – 14 23315 26 12.1 0.15 3 180 0 10 0.15 10 5 – 13 22315 17.6 17.9 0.15 3 240 0 10 0.15 10 5 – 14 23

Tolerance ±0.02 ±3 ±0.02

Table 2 Dual pressure butt-fusion jointing conditions for PE80 and PE100 (Excel)

Fusion Cooling TypicalInitial Min interface interface Cooling Cooling final

Wall Bead up bead soak Max plate stress stress time time out overallOutside thickness interface size Soak interface removal (1st 10 (after 10 in of bead widthdiameter SDR (minimum) stress (approx) time stress time secs) secs) clamps clamps min max

mm mm MPa mm seconds MPa seconds MPa MPa minutes minutes mm mm250 11 22.7 0.15 2 285 0 10 0.15 0.025 15 7.5 15 24280 11 25.4 0.15 3 315 0 10 0.15 0.025 15 7.5 16 25315 11 28.6 0.15 3 345 0 10 0.15 0.025 15 7.5 17 26355 26 13.6 0.15 3 195 0 10 0.15 0.025 10 5 13 22355 17.6 20.1 0.15 3 260 0 10 0.15 0.025 15 7.5 15 24355 11 32.3 0.15 3 385 0 10 0.15 0.025 15 7.5 18 27400 26 15.3 0.15 3 215 0 10 0.15 0.025 10 5 14 23400 17.6 22.7 0.15 3 285 0 10 0.15 0.025 15 7.5 15 24400 11 36.4 0.15 3 425 0 10 0.15 0.025 20 10 18 27450 26 17.2 0.15 3 235 0 10 0.15 0.025 10 5 14 23450 17.6 25.6 0.15 3 315 0 10 0.15 0.025 15 7.5 16 25450 11 41.0 0.15 3 470 0 10 0.15 0.025 20 10 19 28500 26 19.1 0.15 3 250 0 10 0.15 0.025 10 5 15 24500 17.6 28.3 0.15 3 345 0 10 0.15 0.025 15 7.5 16 25500 11 45.5 0.15 3 515 0 10 0.15 0.025 20 10 20 29560 26 21.4 0.15 3 275 0 10 0.15 0.025 15 7.5 15 24560 17.6 31.7 0.15 3 380 0 10 0.15 0.025 15 7.5 17 26560 11 50.8 0.15 3 570 0 10 0.15 0.025 20 10 22 31630 26 24.1 0.15 3 300 0 10 0.15 0.025 15 7.5 16 25630 17.6 35.7 0.15 3 420 0 10 0.15 0.025 15 7.5 18 27630 11 57.2 0.15 3 635 0 10 0.15 0.025 25 12.5 23 32710 26 27.2 0.15 3 335 0 10 0.15 0.025 15 7.5 16 25710 17.6 40.2 0.15 3 465 0 10 0.15 0.025 20 10 19 28800 26 30.6 0.15 3 370 0 10 0.15 0.025 15 7.5 17 26800 17.6 45.3 0.15 3 515 0 10 0.15 0.025 20 10 20 29900 26 34.6 0.15 3 405 0 10 0.15 0.025 20 10 18 27900 17.6 50.9 0.15 3 570 0 10 0.15 0.025 20 10 22 311000 26 38.4 0.15 3 445 0 10 0.15 0.025 20 10 19 281000 17.6 56.6 0.15 3 630 0 10 0.15 0.025 25 12.5 23 32

Tolerance ±0.02 ±3 ±0.02 ±0.01

Butt-fusion Jointing Parameters for Water (WIS 4-32-08 issue 3 April 2002)Heater Plate Surface Temperature: 225°C to 240°C.

48

F R I A T O P A S S E M B L Y A N D O P E R A T I N G I N S T R U C T I O N S

5. Thread the loose end of the tensioning belt into therollers on the twist grip. Pull the belt taut by turningthe twist grip clockwise.

6. Check that the clamping unit is in the untensionedstate (no air pressure at the valve) and then connectthe air pump to the valve. In the unpressurised statethe tensioning figures (1 or 2) are visible in thewindow on the rim of the housing.

7. If necessary make a final correction to the seating ofthe saddle on the pipe.

8. Pump up the clamping unit. (The pressure gauge onthe pump should indicate between 3 and 4bar). Theexpansion of the cylinder will press the saddle ontothe pipe. The gap between the pipe and the saddlemust be completely closed by the pressure applied.A visual check must be made by the user!

9. In the pressurised state the tension number is readoff in the window next to the handle and marked forsafety on the piece of pipe. This will give a check onany fall off in pressure during fusion. If this drop inpressure is no greater than one scale graduation thenthe fusion has been carried out in accordance withthe standard. If the pressure drop is greater than thisthe fusion process must be broken off and the reasoninvestigated. Afterwards, and when the propercooling time has elapsed, a second fusion can becarried out.

Assembly and Operating Instructions forFriatop Top Loading Clamping Unit whenused on Frialen Multi Branch Saddles(250 - 630mm)

Assembling the FRIATOP clamping unit on 250-560mm pipe1. The adaptor is fitted into the clamping unit before

this is tensioned and forms the connection with theFRIALEN® component. It has various steps,depending on the type of saddle fitting being fusedon. If a FRIALEN®-SPA-TL is being fused on, thescrew cap of the fitting is located directly into theunit without the adaptor. The same applies to theVSC-TL.

2. The preparation of the area being fused (scraping,cleaning) is carried out in a similar manner to thedescriptions given in the assembly instructions forFRIALEN® safety fittings.

3. Place the saddle component onto the pipe.

4. Fit the adaptor and the clamping unit onto the saddlecomponent. The different steps in the adaptor fit thevarious types of saddle component. Lay thetensioning belt around the pipe (do not twist it!)


GPSPOLYETHYLENE

49

GPSPOLYETHYLENE


Assembling the FRIATOP clamping unit forSA-TL on 630mm pipe1. The adaptor is fitted into the clamping unit before

this is tensioned and forms the connection with theFRIALEN® component. The required steps vary,depending on the type of saddle fitting to be fused. Ifa FRIALEN®-SPA-TL is being fused, the screw cap ofthe fitting is located directly into the unit without theadaptor. The same applies to the VSC-TL.

2. The preparation of the area being fused (scraping,cleaning) is carried out in a similar manner to thedescription given in the assembly instructions forFRIALEN® Safety fittings.

3. Place the saddle component onto the pipe.

4. The different steps in the adaptor fit the various typesof saddle component. Lay the tensioning belt aroundthe pipe (do not twist it).

5. Thread the loose end of the tensioning ring belt intothe rollers on the twist grip. Remove the slack in thebelt by turning the twist grip clockwise.

6. Check that the clamping unit is in the untensionedstate (no air pressure at the valve) and then connectthe air pump to the valve. In the unpressurised state,the tensioning figures (1 or 2) are visible in thewindow on the rim of the housing.

7. If necessary make a final correction to the seating ofthe saddle on the pipe.

FRIALEN® fusionConnect the fusion cable from the fusion unit to thecontacts on the saddle and start the fusion process.

During the fusion process the tension number should bechecked.

WARNING!

For general safety reasons always stay at a distance ofone metre from the point of fusion during the fusionprocess.

Removing the FRIATOP clamping unitAfter the fusion has finished, always maintain the jointpressure in accordance with point 8 on page 41 for a 10minute cooling period.

After this, the pressure can be taken off by venting theunit to air and the unit dismantled.

Before drilling through please allow to cool down for thetimes listed below:

Cooling times d250 - d630mm = 60min

WARNING!

If the cooling down time is not adhered to the saddlecan come away from the pipe in the area of the fusedjoint. A permanently safe fused joint cannot beguaranteed.

WarrantyThe warranty is six months. It will not apply if there aresigns of force being used or of usage which is not inaccordance with the operating instructions.

Functional safetyThe FRIATOP clamping unit has been checked for safeoperation before being shipped. The equipment requiresvery little maintenance. We recommend a half yearlycheck on all functional parts. The unit should beprotected from dirt.

Assembly and Operating Instructions forFriatop Top Loading Clamping Unit whenused on Frialen Multi Tapping Tees (250 -315mm)FRIALEN® Multi Saddle Components are used with pipesfrom SDR 17 to SDR 11 from 250mm diameter. They areheld in place during fusion by the FRIATOP clampingdevice.

FL615339 Pressure Tapping Fitting - Top Loading250mm - 315mm diameter.

FRIALEN® FL615339 Pressure Tapping Fittings aresuitable for fitting as branch connectors onto non-pressurised or pressurised pipelines.

N.B. For technical reasons FRIALEN® Pressure TappingFittings cannot be used with SDR7 pipes.

50


GPSPOLYETHYLENE

1. Mark out the area of the fusion zone on the pipe (andthe side outlet spigot) and remove the oxide skin byscraping. The fusion zone is the area of pipe coveredby the saddle; for a side outlet, it is the insertiondepth on the smooth pipe spigot. The oxide skin inthe area of the fusion zone, which has formed on thesurface of the HD-PE pipes during storage, must betotally removed before assembly.

N.B. if the oxide skin is not completely removed thiscan lead to an unsatisfactory fused joint, which mayleak.

A single unbroken removal of the surface is adequate(min. 0.1mm). This should leave an uneven surfacewith no flat spots or ridges of material.

N.B.- Filing or using an emery cloth is notacceptable as this can lead to impurities beingembedded in the surface. As a check that theremoval of material from the surface is unbroken andcovers the full area, we recommend the use ofmarked lines to check. If during the scraping processareas of the surface are not scraped (e.g. if the pipeis oval) these must be reworked. Protect the cleanedup zone from dirt, soap, grease, water running backand unfavourable weather (e.g. from effects ofmoisture, the formation of frost).

2. The surfaces of the pipe being fused and the internalsurfaces of the FRIALEN® FL615339 PressureTapping Fitting must be absolutely clean, dry and freefrom grease. Immediately before assembly, and afterscraping, clean these surfaces with a suitablecleaning fluid, using only absorbent non-fibrous, non-coloured paper. We recommend the use of special PEcleaning fluid.

N.B. When using alcohol based cleaners the alcoholcontent must be a minimum of 96%. The cleanermust have evaporated completely before using.

Now, using a marker pen, redraw the line to showthe perimeter of the fusion zone on the pipe sinceprevious markings will have been removed byscraping and cleaning. Take care to ensure that thefusion zone remains clean whilst doing this.

3. Assembly

Place the saddle onto the prepared surface of thepipe.

Fit the clamping device as directed in the operatinginstructions for Friatop.

N.B. On FRIALEN® Pressure Tapping Fittings thedrill setting made at the factory must not be alteredbefore fusing.

After the fusion process has finished always maintainthe jointing pressure for a 10 minute cooling period.

4. Carrying out the fusion

When using FRIALEN® Pressure Tapping Fittings ontopipes carrying a fluid or gas the following maximumpermissible operating pressures must not beexceeded during the fusion process and until coolingdown is complete.

Maximum permissible working pressure in bar

N.B. Only use fusion control units which aredesigned and authorised by their manufacturer toprocess FRIALEN® Safety Fittings. The fusionparameters are contained in a bar code which isaffixed to the FRIALEN® Safety Fitting. Theparameters are entered into the fusion control unitusing the reader wand.

The fusion control units automatically monitor theprogress of the fusion process and regulate theelectrical energy input to within specified limits.

The fitting fusion indicator only gives an indicationthat fusion has taken place. The proper progress ofthe fusion process, however, is only shown by thefusion control unit.

N.B. For the sake of general safety always maintaina distance of one metre from the fusion point duringthe fusion process.

5. Drilling and applying the test and working pressure.

The waiting times below must be adhered to:

The cooling CT given on the components are thecooling times before drilling.

N.B. If the waiting times are not complied with,there is a risk of an unsatisfactory fused joint, whichmay leak. Before drilling, the general installationguidelines must be observed.

Pipe Material PE80 PE100 (Excel)SDR 17.6/17 11 17 11Gas pipe 1 4 4 10Water pipe 8 12.5 10 16

Cooling down time for FRIALEN®

Multi Saddle componentsDiameter Before pressurising Beforein mm Through the outlet drilling (CT)250-500 50 mins 60 mins

51

GPSPOLYETHYLENE


SlimFlange®

This unique design of PE flange is available for PE sizesfrom 250mm to 560mm and permits actual or near boresize-for-size jointing of a PE pipe to the flange of an ironpipe or fitting. This huge benefit is achieved byincorporating a stainless steel hoop in the PE flange faceto provide a reinforcing effect and this allows the PE stubshoulder height to be reduced dramatically. Unliketraditional PE flanges, SlimFlange® eliminates the need toupsize the connected valve or other metal component orto down size the PE pipe (see figure ii).

Connecting PE to iron flanges It is not possible to join polyethylene pipe to pipe madefrom other materials by fusion welding. In the case ofmains pipe sizes it is necessary to use PE flangeadaptors, including SlimFlange®, or specialist fabricatedmetal fittings eg. from Crane-Viking Johnson or Crane-WASK, that grip the pipe.

Since polyethylene systems are end-load bearing,precautions must be taken where connection is made topipe of another material, to prevent pull-out of any nonend-load bearing joints in that pipe line. The transitionmay need to be externally harnessed or anchor/thrustblocked.

In larger pipe sizes there can be a discrepancy (in boresize and bolting) when jointing polyethylene pipe to ironpipe, as PE pipe has much thicker walls. Whenconsidering multi-material piping systems it is importantto remember that PE pipe is always sized by its OD,whereas iron pipe is sized by its nominal bore, referred toas its DN (Diametre Nominal).

For example, a 450mm OD PE100 (Excel) SDR17 pipe(with a bore of 400mm) can be jointed to a 450mmPN16 valve using a traditional 450mm x 450mm PEflange adaptor (see figure (i)). But this means that thebore size between the two components changes from400mm (PE) to 450mm (iron).

F L A N G E C O N N E C T I O N S

Figure (ii) 450mm PE100 (Excel) Pipe and SlimFlange® PEflange adaptor bolted to a DN400 valve.

Figure (i) 450mm PE100 (Excel) Pipe and conventional PEflange adaptor bolted to a DN450 valve.

52

Flange adaptor incorporating a polyethylene reducer

For the sizes where a SlimFlange® cannot be offered (ie.315mm SDR11 and 630mm and above), a possiblealternative is a fabricated fitting incorporating a reducedsize PE flange. Note there is a temporary reduction inbore with this fitting and also it may be desirable toincorporate a metal reinforcing plate between the PEflange and the metal flange to help stabilise the assembly.Please consult our Technical Support Department beforespecifying one of these ‘combination’ flanges.

Steel flange converter

Where the PE and iron sizes cannot be accomodated by aSlimFlange® a better solution is to employ a two-way steelconverter plate. In the diagram below a converter plate isdrilled/studded to allow a direct connection between a630mm PE x 600 PN16 flange adaptor and a DN500PN16 ductile iron flange.

Connecting PE to other pipe materialsPE can be jointed to other pipe materials (e.g. PVC-U,asbestos cement) in the same manner as outlined abovefor iron. If further assistance is required, please contactour Technical Support Department.

Typical bolting torques for flanges (PE to PE or PE to metal flanges)

Standard Flanges SlimFlangesNominal Nominal Torque Nominal TorquePE size Iron size Bolting (Nm) Iron size Bolting (Nm)(mm) (mm) ±10% (mm) ±10%

63 50 M16x4 35 n/a90 80 M16x8 35 n/a

125 100 M16x8 35 n/a180 150 M20x8 60 n/a200 200 M20x12 80 n/a225 200 M20x12 80 n/a250 250 M24x12 100 200 M20x12 60280 250 M24x12 100 n/a315 300 M24x12 120 250 *M20x12 70355 350 M24x16 150 300 M24x12 120400 400 M27x16 200 350 M24x16 150450 450 M27x20 250 400 M27x16 200500 500 M30x20 300 450 M27x20 250560 600 M33x20 350 500 M30x20 300

*non standard bolt size

Figure (iii) 450mm x 400 PN16 ‘combination’ flange adaptor

Figure (iv) 630mm x 600 PN16 flange adaptor with 600 PN16 x 500 PN16 steel flange converter

Mechanical Joints:Recommended procedure for bolting upflange adaptorsFlanged joints should be made using a single full face orCorrugasket® rubber gasket or for more criticalapplications at above 10 bar, steel reinforced gaskets(details on request) of the correct size. All four matingsurfaces must be undamaged, clean and free fromcontamination.

A jointing compound should not be used.

Wherever possible, flange joints should be made beforeother joints are completed. Pipework configuration shallbe such that mating faces are aligned and butted squarelyto each other with a maximum separation of 5-10mmprior to bolting up, irrespective of pipe diameter.

Only clean undamaged nuts and bolts of the correct sizeshould be employed, with standard thick (Form A)washers at both ends, also of the correct size.

Care must be taken to ensure that the gasket is centredproperly between the two flanges before tighteningcommences. The nuts and bolts must be tightened asuniformly as possible using a torque wrench, in diagonallyopposite sequence, progressively from a finger tight start.For example:

Fingertight • 5% of final torque • 20% of final torque •50% of final torque • 75% of final torque • 100% offinal torque.

For PE diameters above 180mm, it is recommended thattwo operators work simultaneously on diametricallyopposite bolts where possible. To guarantee subsequentleak tightness, final torquing up should be repeated afterthe assembly has been allowed to relax for an hour or so.

Evenness of tightening is as important as final torquevalues - see the table below. The torques shown are forSDR11 and SDR17 pipe, in both PE80 and PE100(Excel).


GPSPOLYETHYLENE

53

GPSPOLYETHYLENE


Protecta-Line is a complete PE pipe system solution fordrinking water supply through contaminated land. It is athree layer PE composite barrier pipe which includes analuminium layer on the outside of a standard PE pipe toprevent the ingress of any contaminants into the watersupply.

Protecta-Line pipelines can be jointed using any of thefollowing methods:

• Protecta-Line Mechanical Compression fittings (25-63mm)

• Protecta-Line Fluid Compression fittings (63-180mm)

• Electrofusion fittings (90mm-180mm)

• Butt-fusion (90mm-180mm)

Where electrofusion and butt fusion methods are to beemployed, this should first be cleared with the local waterutility. In both cases local wrapping with aluminium andDenso tape is recommended (available from GPS).

Protecta-Line Standards and Approvals• GPS Protecta-Line pipe can clearly be identified as

multi-layered pipe by means of brown stripes on theouter skin - to comply with NJUG requirements.

• GPS Protecta-Line is a WRAS Approved system

• GPS Protecta-Line is manufactured from a DWI(Regulation 31(4)(a)) approved material.

• Core PE pipe to WIS 4-32-17

P R O T E C T A - L I N E J O I N T I N G P R O C E D U R E S

54


GPSPOLYETHYLENE

55

1. Cut the pipe square. Unscrew the fittings andremove the nut and the white split ring. Slidethese components onto the Protecta-Line pipe,nut first, ensuring the taper on the split ringfaces towards the nut.

2. Tap the insert into the end of the Protecta-Linepipe with a mallet. Ensure the sealing ring iscorrectly positioned on the insert.

3. Slide the split ring along the Protecta-Line pipeuntil it is up against the insert. Snap the nutover the split ring.

4. Screw the nut onto the central section of thefitting body. Continue to tighten the nut until thethread on the central section is no longer visible.

Mechanical Compression Fittings Assembly Instructions

Fluid Compression Fittings - Coupler Assembly Instructions

1. Take the two pipe sections to be joined and inspect theends for any obstruction, removing any large burrs orlips on the pipe ends. Check the pipe ends arereasonably square.

2. Using the marking gauge and a suitable marker pen,mark the appropriate dimension ‘x’ (see chart) from theends of the pipes to be joined.

3. Push the Protecta-Line Fluid Compression insert intoone end of the pipe, making sure that the pipe end isfirmly against the shoulder of the insert.

4. Slide the Protecta-Line Fluid Compression outer shellover the same pipe end that has the insert installed.Make sure that the shell is far enough up the pipe sothat the insert is visible.

5. Push the second pipe over the visible end of the insertand make sure that both pipe ends are against eachside of the insert shoulder.

6. Slide the Protecta-Line Fluid Compression outer shellback over the assembly until the two marks on eachend of the pipe are visible at each end of the outershell. This will indicate that the pipe ends are stillagainst the insert shoulder and that the outer shell ispositioned in the centre of the joint.

7. The joint is now ready for pressurising.

Marking distances:

Pipe sizes ‘x’ mm63 4790 64110 71125 81160 95180 110

mark pipe ‘x’ mm from end of pipe

STEP ONE

ensure mark lines up with end of sleeve

STEP TWO

ensure mark lines up with end of sleeve

STEP THREE

GPSPOLYETHYLENE


Pressurising the joint

1. A calibrated hydraulic pump must be used for allpressurisation of the Protecta-Line Fluid CompressionFitting range. The pump must be filled with Protecta-Line vegetable oil pressure fluid.

2. Remove the ‘slide-on’ nipple connector from its parking‘nipple’ on the hydraulic pump. Slide the nippleconnector over the nipple on the Protecta-Line FluidCompression fitting. Please note that the nippleconnector is a slide fit over the nipple, not a push fit.

3. Gently raise and lower the pump handle, watching thepressure gauge. As the pressure gauge reaches 260bar,the pressure breaker valve will activate and the pumphandle will fall freely with no resistance. This indicatesthat the required pressure has been achieved. Wait 10seconds and repeat the pumping action until the pumphandle ‘breaks’ again. Wait 10 seconds and repeat again. The pressure gaugeshould now show a steady reading of approximately260bar. The joint is now made.

4. The pressure must be released before removing theslide-on fitting connector from the Protecta-Line FluidCompression shell: lift the manual relief valve for 2seconds then slide off the fitting connector from theProtecta-Line Fluid Compression fitting.

WARNING! Pressure within the fitting may be released whileremoving the connector, causing a momentarydischarge of fluid. SAFETY EYE PROTECTION MUST BE WORN.


GPSPOLYETHYLENE

57

Repairs

• Remove damaged section ‘L’ as required

• Mark pipe ends left in ground ‘X’ mm from ends usingthe repair gauge and marker pen

• Cut length of new pipe L - 2Y long and mark ‘X’ mmfrom end. For minimum length ‘L’ see table. Note Y = insert linerspigot length + shoulder

• Slide repair shells over new pipe and place inserts intoends with the shorter end of the insert protruding

• Place new pipe section in line with the existing pipeand move inserts to new position with collar againstexisting pipe ends

• Slide shells into position so that marks previously madeline up with the ends of the shells

• The joints are now ready to be pressurised

Pipe Size X 2Y Min ‘L’

63 47 108 40090 64 142 536

110 71 158 596

125 81 176 672

160 95 206 788

180 110 236 912

• If for any reason the nipple needs to be removed, thepressure in the fitting must be released first by usingthe pressure release tool.

• Check that the marks on the pipe still line up with theend of the fitting.

• The joint is now complete.

Electrofusion Fittings

Standard electrofusion procedures must be adhered to,but please note the following additional points:

ScrapingIt is essential that the Protecta-Line pipe is properly preparedprior to electrofusion jointing. Itis necessary first to remove theouter polyethylene coating andaluminium barrier. The Protecta-Line SurprepScraper must be used for pipeend preparation as thisequipment not only removes theouter layers, but prepares thecore pipe for electrofusionjointing at the same time.

NB: Two sizes of Protecta-LineSurprep Scraper are available,one designed to fit 90mm to110mm pipe and the other to fit125mm to 180mm pipe.

SafetyIt is potentially dangerous to carry out electrofusionjointing where the aluminium barrier layer is still in place.

Clamping All electrofusion joint assemblies must be held in clampsthroughout the fusion and cooling periods.

NoteElectrofusion jointing is not be used for Protecta-Linepipes of 25mm, 32mm and 63mm.

Procedures for Using ElectrofusionFittings on Protecta-Line Pipelines

GPSPOLYETHYLENE


Procedure for using the Protecta-Line Surprep Scraper is as follows:

1. Measure the insertion depth of the electrofusion fittingto be used. Place a mark on both pipes to show theposition where the edge of the fitting will be.

2. Clamp the pipe to beprepared taking care to avoiddamage to the pipe’s outercovering.

3. Separate the mandrel fromthe body of the Protecta-LineSurprep Scraper.

4. Hold the expanding plug androtate the mandrel anti-clockwise until the plug is alight interference fit in the pipebore.

5. Push into pipe until edge ofplug is level with edge of pipe.Expand plug further using the10mm ring spanner. Do not over-tighten in order toavoid pipe distortion.

6. Slide the body of the Protecta-Line Surprep Scraperonto the mandrel, depress the release button andposition the cutter close to the edge of the pipe.

7. Note: Protecta-Line Surprep Scraper cuts in an anti-clockwise direction, beginning at the end of the pipe.

8. Rotate the knob on the top of the tool post through90°, against the spring tension, such that the cutter isin its raised position.

9. Loosen the body thumbscrew and position the cuttershoe on the edge of the pipe. Tighten thethumbscrew.

10.Rotate the knob on top of the post through 90° sothat spring pressure is applied to the cutter.

11.Rotate the tool anti-clockwise in a smooth continuousmotion to remove the outer layers in a continuousstrip. Stop cutting when the socket depth mark isreached.

90° Thumbscrew

Surprep body

Mandrel release button

Ring spanner

Expanding plug

Toolpost

Cutter

Important InformationSome Water Utilities have a technical requirement thatonly full barrier fittings are used with Protecta-Line pipe.Where a Water Utility stipulates this, GPS recommendsthe use of Protecta-Line Fluid Compression Fittings forsizes above 63mm (Protecta-Line mechanical compressionfittings for sizes up to 63mm also provide for a fullbarrier).

Where Electrofusion or butt fusion is acceptable to theUtility (in sizes 90mm to 180mm), GPS recommendssubsequent wrapping with aluminium foil and a ‘Denso’type tape.


GPSPOLYETHYLENE

59

12.Rotate the knob on top of the tool post so that thespring pressure is released.

13.Use the hand scraper to remove the peeled strip from the pipe. Caution do not attempt to break the peeled strip bypulling with bare hands, it has a sharp edge!

14.Inspect the prepared surface to ensure: i) All of the metallic layer has been removed.ii) All of the adhesive which bonds the metallic layerto the blue core has been removed.

15.If, for any reason, the prepared surface is not auniform blue colour all over, use the hand scraper tocomplete the preparation process.

Never attempt a second pass with the Protecta-Line Surprep Scraper.

Butt fusion

Where this is allowed by the local Utility it is importantthat the outer PE and aluminium skins are removed farenough back, using the Protecta-Line Surprep tool, toprevent the aluminium from coming into contact with thebutt fusion machine trimming or heater plates.Furthermore, the skins should be removed far enoughback to permit normal debeading of the completed jointfor quality control purposes.Care should be taken not to damage the outer skins ofProtecta-Line pipe when clamping it in the butt fusionmachine. In the case of some machines this maynecessitate gently radiusing the edges of the jaw shutlines.

Wrapping Procedure forElectrofusion and Butt-fusion

When additional protection is requested, it isrecommended that Protecta-Line aluminium tape iswrapped around all butt-fusion and electrofusion joints.

To limit the risk of subsequent damage by third parties, itis further recommended that the aluminium tapewrapping is protected with a layer of Denso tape orequivalent waterproof tape.

The following procedure should be followed:

1. Following the jointing of Protecta-Line pipe withelectrofusion fittings or butt-welding, the complete jointarea should be wrapped with Protecta-Line adhesivealuminium tape. In the case of electrofusion, theterminal pins should first be sawn off.

2. After completing the jointing procedure the whole jointsurface should be dry and clean. Care should be takento ensure that when wrapping electrofusion joints withthe adhesive aluminium foil the extremities of the jointare wrapped using a 100% overlap and the main bodyarea with a 50% overlap.

3. Additional protection can be afforded by furtherwrapping the aluminium wrapped joint area withDenso or other equivalent waterproof tape. (Specificproduct advice should be requested if products otherthan those referenced are to be used Telephone: +44(0)1480 442620)

GPSPOLYETHYLENE


Testing & Commissioning ofProtecta-Line Pipelines

The sequence of events for Protecta-Line includes thebasic procedures (on page 17) taking the extra careappropriate for a contaminated environment as set out bythe Local Water Undertaking.

As for normal PE pipes these standards will normallyrequire, as a minimum, the adequate flushing of theservices and the testing of all pipes and joints to themaximum head to which the system is to be subjected.

The GPS Secura-Peel Pipe Preparation tool should beemployed to remove the polypropylene coating fromSecura-Line pipe prior to joints being made.

Basic principles of skin removalSecura-Peel comprises a guidance platform/body, cutterand head. The cutter features an anvil to limit the depthof cut and avoid damage to Secura-Line’s core pipe. Thetool is supplied with full operating and maintainanceinstructions, but the basic principles are set out below. Itis easiest in the first instance to use a pushing action topenetrate the pipe skin, and a pulling action for cutting.The guidance platform is omnidirectional (works in alldirections), but the cutter may be readily rotated tofacilitate a change in direction of cut, without lifting fromthe pipe – however, always rotate the cutter and handle ina clockwise direction to maintain position of the cutterunder the skin.

Preparation method for pipe ends prior to jointing

1. Hold the fitting against pipe end and mark the Secura-Line skin at a distance from the pipe end equal to thelength of the fusion zone plus 10mm.

2. Align the pointed side of the handle in acircumferential direction and press the blade into theSecura-Line skin where marked. Pull the tool aroundthe pipe circumference keeping the cutting distancefrom the end of the pipe constant.

3. When the cutter meets up with its starting positionturn through 90 degrees and push or pull to the end ofthe pipe.

4. Lift, peel back and discard skin without touching thepipe surface underneath.

5. Do not touch the exposed surface with your hands orwith any rags.

6. Continue the jointing procedure in the normal way asfor standard PE pipes.

Preparation method for installation of Tapping Tees andBranching Saddles.

1. Remove the fitting from its bag, leaving the cardboardprotector in position. Place the fitting on top of thepipe in the desired position.

2. Mark north, south, east and west positions around thefitting on the pipe, using a felt tip pen.

3. Remove the fitting and extend the lines to draw asquare on the pipe where the fitting will be joined.

4. Using the Secura-Peel tool, push the cutter head intothe pipe skin.

5. Once the PP skin has been pierced, pull the tool (byholding the platform) towards you along the full lengthof the line marked.

6. At the end of the line, rotate the tool to the right (byholding the platform) always working clockwise aroundthe marked area.

7. Repeat along all marked lines.

8. Upon completion, remove the polypropylene skin. Donot touch the exposed surface with your hands or withany rags.

9. Continue the jointing procedure in the normal way.


GPSPOLYETHYLENE

61

S E C U R A - L I N E J O I N T I N G P R O C E D U R E S

GPSPOLYETHYLENE

P U S H F A S T S Y S T E M P R O C E D U R E S


The SystemThe basic element of the Push-Fast system is the speciallydesigned patented socket. Standard 6m lengths of pipeare supplied with a factory welded socket on one end.

A range of complementary fittings is available with plain,socketed or flanged ends, based on Long Spigot fittings.

Jointing ProcedureIt is important to remember that the performance of the Push-Fast joint depends on the efficiency of the sealbetween the elastromeric sealing ring, the pipe and thesocket. Damage to the pipe or fitting or the presence ofdirt or grit will adversely affect the performance of thejoint.

Factory fitted protective packaging should be left inposition until the components are ready for use.

Joints between pipes and fittings are made using thefollowing procedure:

1. Remove protectors from spigots and sockets andinspect for damage. Particular attention should begiven to any scoring of the spigot. Scored spigots mustbe cut back to an undamaged section.

2. Push-Fast pipes are supplied with a factory machinedchamfer. Any site cut pipes should be cut square andsimilarly chamfered.

3. Inspect the elastromeric sealing ring, and therespective locating grooves for any damage and replaceif necessary. If dirt or grit is present, the seal must beremoved and the seal groove and socket thoroughlycleaned of all foreign matter before refitting thecomponents.

4. Similarly inspect the ‘grip’ ring and groove. Clean asnecessary to remove any foreign matters but do notremove the ‘grip’ ring from the socket groove.

GeneralThe Water Industry has traditionally used spigot and socketjoints for buried mains, the pressure tight seal beingaffected by a rubber ring seal contained within the socket.Such methods are employed for ductile iron and PVC-Upipework.

Notwithstanding the reliable methods of weldingpolyethylene pipe and fittings, the need still exists for apipework system which offers the advantages ofpolyethylene material but which still employs conventionalspigot and socket jointing techniques.

Recognising this need, GPS offers the Push-Fast System inblue and black PE80 (MDPE) and PE100 (Excel) materialsand in PE sizes from 90mm to 250mm. Unlike most of theconventional spigot and socket systems Push-Fastincorporates a ‘grip’ ring. Made from a hard thermoplasticmaterial the ‘grip’ ring enables the Push-Fast joint undermost circumstances to withstand the end-loads induced,initially by the test pressure, and subsequently by thecontinuous working pressure, up to a maximum of 16bar.This largely eliminates the need for thrust blocks, while stillallowing simple low force jointing. This system is covered bya GPS patent. Please consult our technical supportdepartment for advice when Push-Fast is to be installedabove ground or might be pressure tested before backfilling, especially where there are changes in direction orwhen pressures above 10 bar are likely for diameters above180mm.

ApprovalsThe Push-Fast system has undergone extensive testing andtrials to prove the long-term performance, and has YarsleyTestguard Product Conformity certification.Testing to WRc 4-32-03 and 4-32-04 has shown that theperformance requirements of these documents are fully met. Tests for angular deflection and performance under variablepressure conditions have also been successfully completed.

Many UK Water Authorities, Water Companies and RegionalCouncils use the Push-Fast System including:

Lothian Regional CouncilThames WaterRickmansworth Water CompanyWelsh WaterSouthern WaterYork Water CompanyMid-Kent Water

Section through Push-Fast assembled joint showing grab ring intaper and elastromeric seal.

62

GPSPOLYETHYLENE


5. When all components are clean, care must be taken toensure that they remain clean by replacing protectorsor plastic bags over the ends unless jointing is to becarried out immediately.

6. The spigot ends of any site cut pipes should be markedwith the insertion depth, using a felt tip pen, asfollows:

Pipe size Insertion depthmm mm90 152110 131125 143160 194180 202225 230250 250

7. Apply the GPS Push-Fast lubricant, spray or gel, to thespigot, and to the grip ring and the elastromericsealing ring in the socket.

Typical usage of lubricant is as follows:

No. of joints per 400g spraySize or 500g tub of gel90 100

110 80125 60160 30180 30225 25250 20

8. Align the pipe and fitting and enter the spigot into themouth of the socket. Apply sufficient force to the endof the pipe/fitting remote from the joint so that thespigot enters the socket up to the marked insertiondepth. Smaller sizes should be entered using handapplied force, whereas assistance of a crowbarpurchasing on a wooden block may be necessary forthe larger sizes.

9. Under no circumstances must joints be pushed homeusing mechanical equipment, ie. a digger bucket.

Repairs/AlterationsThe most satisfactory and safest method of effectingalterations or repairs to a Push-Fast system is to followthe procedure previously described using the GPSDuraFuse electrofusion techniques.

A repair or slip coupler is included in the Push-Fast range,however, the design of the coupler is such that it will notwithstand end thrust loadings. This may therefore causecomplications where a system has initially been installedwithout the provision of anchors or thrust blocks.

In addition, repair or slip couplers must not be used torepair long runs of polyethylene pipes as the joint isunlikely to accommodate the axial movement that mayoccur.

There is also the possibility that the pipe outer surfacemay have been damaged or scored to the extent thatpositive sealing cannot be achieved.

However, having checked that the above situations do notor will not arise, the following procedure should befollowed:

1. Cut out the damaged section over a sufficient length toensure that the remaining pipe surface is not damagedbut in any event to a minimum of 600mm.

2. Ensure the pipe ends are square and chamfer theends.

3. Clean the outer surfaces of pipe on each exposed endof the main being repaired for at lest the equivalentlength of the slip coupler.

4. Using a felt tip pen, mark each pipe end to half thedepth of the coupler.

5. Lubricate these two ends and push a slip coupler overeach end until the pipe ends touch the secondelastromeric sealing ring.

6. Cut a new length of pipe to fit between the ends of therepair coupler. Again check that the ends of this pipeare also cut square and are chamfered.

7. Lubricate the ends of the new pipe and place inposition.

8. Pull the slip couplers back over the new length of pipeuntil the insertion depth marks are just visible.

Push-Fast fittings are not available in service sizes.DuraFuse electrofusion fittings have to be used as doDuraFuse electrofusion tapping tees to achieve serviceconnections to the main.

63

180mm

160m

m

Flow out

Flow in

Flow out

Flowin

h

Incomingpipe

GPSPOLYETHYLENE


Assembly Instructions

1. Secure a concretebase into the groundand fit 4 x M16 boltsat 180 x 160mmcentres. (Bolts notincluded in kit)

4. Cut the length of thepupped stub flangeas required. Notethat the total height(h) should includethe Fire Hydrantheight. Scrape thestub flange pipe endand place in the topof the electrofusiontee. Electrofuse thetee, securing thebase and stub intoplace.

D U C K F O O T B E N D K I T S

2. Fix and bolt the DuckFoot Bend base pieceto the concrete base.Note that theorientation of thebase should be suchthat the incomingflow meets the faceof the Duck FootBend base.

3. Remove the lowerpipe stop from theelectrofusion tee andpush firmly onto thebase. As for part 2,the orientation of theelectrofusion equaltee should be suchthat the incomingflow meets the faceof the Duck FootBend base.

5. Electrofuse thecoupler, reducer orspigot reducer intoplace and electrofuseto the incoming pipe.

6. Connect the hydrantto the stub flangeassembly followingthe stub flangebolting procedure.

64


GPSPOLYETHYLENE

If you would like to receive further information regarding other GPS products, pleasephotocopy this page, tick the information you require and fax back to us on +44 (0)1543 273 232

FAX BACK

Name ...............................................................................................................................................................................

Company name..................................................................................................................................................................

Address.............................................................................................................................................................................

.................................................................................................. Postcode .......................................................................

Tel .............................................................................................. Fax ...............................................................................

Email ................................................................................................................................................................................

Fax: +44 (0)1543 273 232

Polyethylene Pipe

DuraFuse Electrofusion Fittings

Fabricated Products

Spigot Fittings

Large Diameter Tees

SlimFlange

Sleeved Subcoil®

Secura-Line

PushFast

Duck Foot Bends

Calder Electrical and Mechanical Jointing Equipment

Protecta-Line

Distributor

G0009/1 September 2004

GPS reserve the right to modify products without prior notice.Reproduction of any of the images in this brochure is not permitted without the written consent of GPS. For information, please contact Marketing Communications via [email protected] or Tel: +44 (0)1543 273213

Whilst every effort is taken to ensure the accuracy of information contained within the brochure, the details are offered in goodfaith and GPS accepts no liability for matters arising as a result of errors or omissions. Should this information conflict with yournormal engineering advise, please contact our technical support department on +44 (0)1480 442620.

A PDF version of this brochure is available from our website.

UK EnquiriesSt Peter’s RoadHuntingdonCambridgeshirePE29 7DATel: +44 (0)1480 52121Fax: +44 (0)1480 458829

email: [email protected]: www.gpsuk.com

Export EnquiriesWalsall Road CannockStaffordshireWS11 9NSTel: +44 (0)1543 279909Fax: +44 (0)1543 279450

GPSPE PIPE SYSTEMS

installation & tech. guidlines - alpha pipelines homealphapipelines.co.nz/pdf's/pe...

Documents