WATER PRESSURE SYSTEMS

TECHNICAL HANDBOOK

PRESSURE SYSTEMS

WATER PRESSURE SYSTEMSCONTENTS

PageProduct Data 2 Introduction 3

Range 7 Range 8

Design 13 Hydraulic Design 14Thrust Restraint 18Surge and Fatigue 20External Compressive Loads/Temperature De-rating 21Chemical Resistance 22

Sitework Instructions 26 Handling and Storage 27Jointing 28End Load Joint Installation 30Deflection and Curvature 31Water Services Connections 32Flange Jointing 33Inspection and Testing/Installation Above Ground 34Bedding Requirements 35Compaction Fraction Testing 36

Jacking Pipe 37 Jacking Range 38

General Information 39 Conversion Chart 40

PRESSURE SYSTEMS1

PRODUCT DATA

PRESSURE SYSTEMS

Introduction

The Water Pressure System offersa range of PVC-A (PVC Alloy) pressurepipes and fittings purpose-designed to meetthe specific requirements of the distributionand trunk Sectors of the water industry.The * Water Pressure Systemcomprises pipe and fittings in the diameters90mm to 710mm and includes the End Load Joint.The system isavailable in blue and black for potable waterand sewerage applications respectively.

The system offers Engineers, Contractorsand Water Companies a new level ofperformance and confidence, combining thebenefits of traditional materials with thelatest understanding in plastics technology.The development of this plastics alloycombined with the fittings range has givenspecifiers a new option in the design ofpipelines carrying potable water andsewage.

From the initial success of the launch ofpipe Hepworth have concentrated

further developments in the sewage sectorto optimise the benefits of the system for the end user.The addition ofblack pipe to the range enables watercompanies to specify for bothclean and dirty water thereby optimisingnew pipelines for all mains applications.

Development

The development of pressure pipe systemshas been rapidly progressing in recenttimes. Every new development in thematerials or jointing designs of thesesystems has claimed to eliminate orminimise at least one of the drawbacksof previous products and offer furtherbenefits to the end users.This ongoingsearch for the perfect pipeline has nowexhausted most of the commerciallyavailable materials and technologies.

Hepworth undertook a five year researchand development programme to identifya new pipe material and enhanced jointingtechnology that would meet therequirements of Water Companies andEngineers.

The result was , a unique blendof materials forming a plastics alloy to givesignificant improvements over traditionalmaterials.

Description

The Water Pressure System hasbeen specifically designed for the transportof potable water and sewage.The systemcomprises pipe and fittings in diametersfrom 90mm to 710mm and is available in 8,10, 12.5 and 16 bar pressure ratings, in bluefor potable water and black for sewageensuring its suitability all applications fromdistribution to main trunk lines.

The system significantly improvesperformance in three key areas:

1) Water LeakageMinimising the long term risk of waterleakage either by long term pipe failure,corrosion or joint failure.

2) Water QualityMaintaining water quality by control ofcontamination and pH values, and theavoidance of cement linings combinedwith a smooth bore to reduce the riskof tuberculation and encrustation.

3) Whole Life CostExtended design life coupled withoptimum installation costs and lowmaintenance costs give the system thelowest overall life cycle cost of anywater pressure system.

The system has been designed foruse in new lay open cut situations and iscompatible with all modern methods oflaying including ‘Narrow TrenchingTechniques’.The range offerssimple, quick and correct installation whichis of paramount importance in the pursuitof efficient utilisation of resources.

Specification

The Water Pressure System meetsthe requirements of BS PAS 27,‘Unplasticized poly(vinyl chloride) alloy(PVC-A) pipes and bends for water underpressure.’

This specification gives the requirementsfor a new generation of unplasticizedpoly(vinyl chloride) based plastics alloyPVC-A pipes exhibiting a combination ofhigh strength and ductility. Pipesconforming to this specification will providesystems with a high level of integrity andpredictable performance.

The specification details the propertiesrequired of pipes, integral jointsincorporating elastomeric sealing rings andbends formed from pipes made from

for use for the conveyance of colddrinking water and other fluids for belowand above ground use.The requirementsinclude material properties, dimensions,quality control and type tests, effects onwater quality, and marking.

Elastomeric sealing rings are manufacturedfrom EPDM and conform to Type WA ofBS EN 681-1 1996.

Quality Assurance

Hepworth have an unparalleledcommitment to quality through theinnovation of new products.

The range is certified toBSI PAS 27 under the Kitemark LicenceCertificate KM 45187.

The system is manufactured at ourPadiham site in Lancashire which is listed inthe BSI Register of Firms of AssessedCapability certificate of registrationFM 01415 to ISO 9002.

Water Quality

pipes have been tested inaccordance with the DWI requirementsof Regulation 25, contained in thedocument ‘Guidance notes on the approvalof substances and products used in theprovision of public water suppliesDecember 1993 revision’.A copy of theDWI certificate is available upon request.

This also includes the requirements laiddown in BS 6920.

Resistance to BiologicalAttack/Growth

water pressure systems will notdeteriorate under attack from bacteria orother micro-organisms and will not providea food source to micro-organisms, macro-organisms or fungi.

Recent research has shown that certainelastomeric sealing rubbers can besusceptible to the support ofmicrobiological growth.The water industryhas specified that elastomers for use assealing rings in potable water pipes shouldnot be capable of supportingmicrobiological growth

The Seal is manufactured fromEPDM (Ethylene Propylene DieneMonomer) which has been listed by theUnited Kingdom Water Fittings BylawsScheme for use with potable water.

Hepworth jointing lubricant has beensimilarly tested and approved for use withpotable water.

* Note references in this hanbook forrefer to pipe extrusions.

BSI PAS 27KM 45187

3

Material Description

pipes are manufactured from aunique plastics alloy of three principalmaterials:

● Chlorinated Polyethylene (CPE)

● Polyvinyl Chloride (PVC-U)

● Specially selected Acrylic Derivatives

Each material has been carefully selectedand blended together to give an alloy ofexceptional toughness and durability.The alloying of these materials hasproduced an ‘engineering plastic’ uniquelydesigned to meet the exacting demandsof the water industry.

By combining the tough ductilecharacteristics of PE with the high strengthcharacteristics of PVC-U, a new level ofmaterial performance has been achieved.The material properties are such that highlevels of fracture toughness are combinedwith a high yield stress (ductility) thusgiving certain material performances inexcess of the traditional plastics materialssuch as MDPE, HPPE and PVC-U, as shownon the following pages.

Some of the fittings used in the range may be manufactured from othermaterials, such as PVC-U and aluminium.

Material Testing

An extensive testing programme has beenundertaken to prove the performancecharacteristics of .

These tests were conducted in thelaboratories of Pipeline Developments Ltd,material consultants to North WestWater plc.

● Tensometer Test:Samples of material with a dead sharpnotch are loaded until the samplebreaks.A large white plastic zone isgenerated and causes the initial crackto become blunt which preventsembrittlement. only fails in atough ductile manner.

● C-Ring Test:To evaluate performance under longterm loading, rings are cut from pipe and notches are machined on tothe surface.These rings are then loadedfor many hours in bending. hasnever failed in a brittle manner.

● Impact Test:Impact damage is a common problemduring pipe installation.Testing wascarried out by dropping 25kg weightswith a 2cm striker onto pipe sections.The striker always bounced off leavingonly minor indents.

● Fatigue Test:Because pumps and valvesopen/close/start/stop intermittentlysurges can occur on a regular basiscreating a fatigue condition. Cyclicloading tests where loads have beenapplied to notched samples in a diurnalcycle show that there is no reductionin performance and the materialremains ductile.

● Point Load Test:Although granular bedding is alwaysspecified, pipes can often be laid on topof boulders, bricks or rocks.This causespoint loading and is responsible formany failures in pipelines.yields and deforms, greatly reducing therisk of failure.

● Pressure Test:is designed with a factor of

safety of 1.4. Pressure testing both inthe laboratory and in field conditionshas been carried out to validate thedesign theory and to confirm the factorof safety used.

● Joint Test:Extensive tests in the labs and overthirty years experience in the field haveshown this simple push-fit joint to behighly successful. Experience has shownthat push-fit joints are easy to assembleand perform satisfactorily providedthat:

i Full lubrication of the spigot. Beddingmaterial and contamination of thesealing area are prevented from foulingthe joint.

ii Joints are not deflected to a pointwhich can deform the sealing surfaces.

All tests were successful in proving thematerial performance for the transportof liquids under pressure.The material has the most predictable longterm performance characteristics of anypolymer tested to date.

Testing has also been carried out on avariety of field sites since 1990.Water Pressure Systems have beensuccessful and are now used by WaterUtilities throughout the UK and overseas.

Case studies detailing sites areavailable from the Hepworth literatureservice on request.

4

Material Performance

The system utilises the concept ofpurpose-designed materials aimed atproducing the optimum performancecharacteristics for the specific applicationof transporting potable water and otherliquids under pressure.The result of thisapproach is a cost effective solution givingconfidence to the designer and installerthrough:

● High Toughness

● Predictable Regression Characteristics

● Ductile Behaviour Under Load

The toughness of the material isclearly demonstrated by the results shownin Figure 1. Not only are the initial valueshigh, but regression through time is far lesspronounced than for other materials.

Throughout the test programme thematerial has been characterised by

predictable behaviour patterns resulting invery close correlation with mathematicalprojections of performance. Figure 2 showsa comparison of the effect of point loads,and clearly demonstrates the predictablebehaviour of the material.

In all of the tests currently used to evaluateboth toughness and crack resistance, thebehaviour of the material hasalways been ductile, with failure onlythrough ductile tearing.

Regression data for materialcontaining 25% deep notches is consistentwith results from unnotched samples asshown in Figure 3. Notching the pipe doestherefore not effect the materialproperties. In practical terms this isimportant in terms of site abuse/poorinstallation and subsequent long termperformance.

It is also an important characteristic indetermining the design of the End LoadJoint.This style of joint, utilising the grabring technology, is only possible with amaterial that is not susceptible to notchingand brittle failure. is thereforeideally suited to this system.

The slow crack growth resistance indicatedin Figure 4 is exceptionally good.Thematerial is as resistant to cracking as HPPEand considerably better than ABS.Thisensures that small discontinuities or stressconcentrations, such as sharp objects in thepipe bedding do not slowly develop intocracks over long periods of time.

Hep O

0

0.1

1.0

10.0

0 0 1 10 100 1000 10000 100000

Kic (MN/m3/2)

Failure Time (h)

Tough HPPE

PVC-U

Poor HPPE

Figure 1 Fracture Toughness Data for Various Polymers

Figure 2 Effect of Point Loading on Notched Pipes

Figure 3 Effect of Notches on Pressure Regression

0

1.0

100

1 10 100 1000 10000 100000 1000000

Stress (MPa)

Failure Time (h)

Standard Pipe

Hep O + Notches : Pressure Resistance Unaffected

PVC-U

3 kN Point Load Applied Above Notch in Bore

Point Loading

Defect in wall

Notched Pipe + Point Load

Hep O

10-1 100 101 102 103 104 105 10610

100

Hoop Stress (MPa)

Failure Time (h)

Unnotched Hep O

Notched

Notched PVC-U

PVC-U

Crack Size : a=2.5 mm

NWW 17.5 MPa Design Stress

WIS 4.31.06 Design Stress for PVC-U

50 Years

28 MPa

Hep O

5

The data established through extensivelaboratory and site trial work has developeda confidence in the design ofmaterial.This has been reflected in a factorof safety of 1.4.

exhibits very predictable long-termperformance characteristics which allow arelatively high design stress of 17.5 MPa tobe adopted.The pipes have a combination ofhigh strength and high ductility.

Chemical Resistance

pipe and fittings give excellentresistance to aggressive environmentswhether naturally occurring or as a result ofindustrial activity.

Further details on the chemical agents likelyto be encountered either from groundcontaminants or within the water beingtransported and the resistance of can be found in the Design Section of thisguide.

Material Properties

has the following properties:

Specific Gravity 1390 kg/m3

Young’s Modulus 2500 MPaCoefficient of Thermal 7 x 10-5/KExpansionPoisson’s Ratio 0.38Colebrook-White Surface 0.003 mmRoughnessHazen-Williams C-Factor 150

Jointing Technology

Introduction

Recognising the need for fast and efficientinstallation, Hepworth have developed theEnd Load Joint that can be used inconjunction with the standard Loc-Ringsealing joint when thrust restraint isrequired.The overall aim is to produce apressure system that can be installedcorrectly in all conditions without the needfor complicated welding systems or forlaying concrete to produce thrust blocks.The reduction in installation time requiredand its simplicity are key to the optimisationof installed cost.

Loc-Ring Joint

currently utilises two types of jointin the system.The Loc-Ring joint which hasbeen used in Hepworth Push-Fit pressuresystems for some years.We are alsointroducing the Forsheda Power-lock systemin certain sizes which simplifiesmanufacturing. Its performance is equal orbetter than the Loc-Ring system.

The Hepworth Loc-Ring Integral Joint hasachieved world-wide recognition because ofits innovative design and extremely

successful life history.The simple push-fitsystem is easy to use on site in allconditions for all sizes of pipe.There are norequirements for complicated weldingequipment or lengthy preparation work toslow down installation.

The joint incorporates a triple compressionseal, manufactured from EPDM rubber,which is resistant to both positive andnegative pressure.As a safeguard againstmisuse the rubber sealing ring is locked intoposition during manufacture.The long sealdepth ensures that the pipe will not ‘flip’ outduring installation whilst allowing a degreeof flexibility within the system.

End Load Joint

A pipeline operating under internalpressure will generate thrust forces at anychange of direction, reduction in diameter,blank end or closed valve.This couldpotentially cause the joint to separate thuscausing serious operating problems.

The End Load Joint is the solution to thrustrestraint, combining easy installation with anew high technology design.

The design utilises enhanced ‘grab ring’technology locking the pipe into place bysimply tightening the three restraining bolts(see installation details in Sitework Section).The use of grab rings is made possible dueto the notch resistance capability andinherent stiffness (avoidance of creep) of the

material, currently not availablewith traditional plastics materials.

Hep O

Hep O

0

60

50

40

30

20

10

Crack Resistance (kJ/m2)

Crack Growth (mm)

ABS

HPPE

R

& HPPE have same crack growth resistance

0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6

Figure 4 Resistance to Slow Crack Growth

6

RANGE

PRESSURE SYSTEMS

Range

Pressure Pipes - Single Socket

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630 710

A Outside Min 90.0 110.0 160.0 200.0 250.0 315.0 400.0 450.0 500.0 630.0 710.0Diameter Max 90.3 110.4 160.5 200.6 250.8 316.0 401.0 451.0 501.0 631.0 711.0

T Wall 8 Bar Min – – 3.7 4.6 5.7 7.2 9.1 10.2 11.4 14.3 15.9Thickness Max – – 4.2 5.3 6.6 8.1 10.2 11.4 12.8 15.7 18.0

10 Bar Min – 3.1 4.4 5.6 6.9 8.8 11.1 12.5 13.9 17.5 19.8

Max – 3.6 5.1 6.5 7.9 9.9 12.4 14.0 15.5 19.5 22.1

12.5 Bar Min 3.1 3.9 5.7 7.0 8.8 11.0 13.9 15.7 17.5 22.0 24.5

Max 3.6 4.4 6.6 7.9 9.8 12.3 15.5 17.3 19.5 24.4 27.2

16 Bar Min 4.0 4.8 7.0 8.7 10.9 14.0 17.5 19.7 21.9 27.5 30.1

Max 4.6 5.6 8.0 9.8 12.2 15.4 19.5 21.9 24.3 30.4 33.5

Weight (kg/m) 8 Bar – – 2.9 4.8 7.4 11.6 19.1 24.3 30.1 48.0 57.3

10 Bar – 1.7 3.6 5.7 8.8 14.0 22.8 29.2 35.9 58.0 70.8

12.5 Bar 1.4 2.1 4.5 7.0 10.8 17.1 28.0 35.7 44.3 71.3 86.9

16 Bar 1.7 2.6 5.4 8.5 13.2 21.2 34.5 44.1 54.3 87.2 105.9

Colour Blue ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

Black ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓ ✓

A

TPipe - 6m Effective Length

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630 710

D Insertion Depth Min 140 160 190 210 235 265 290 300 315 360 420

S Seal Depth Min 60 75 86 100 115 125 138 150 170 189 200

A Outside Diameter Max 135 150 215 260 315 395 500 560 610 770 830

Loc-Ring Joint Detail

A

D

S

Note: All dimensions are in mm unless otherwise stated.

8

Long Radius Bend 90°- Single Socket

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630

R Radius 300 350 665 1005 1110 1410 1795 1820 2325 –

L1 Length 600 675 970 1310 1520 1840 2230 2225 2830 –

L2 Effective Length 747 839 1164 1522 1759 2100 2525 2563 3152 –

Weight (kg/m) 10 Bar 2.1 2.9 7.8 15.9 27.8 51.4 98.8 127.7 189.5 –

16 Bar 2.5 4.2 11.5 23.0 41.2 77.2 148.4 191.0 285.8 –

L1

L2

Long Radius Bend 45°- Single Socket

L 1

L2

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630

R Radius 300 350 665 1005 1110 1410 1795 1820 2325 2390

L1 Length 417 460 566 700 845 983 1140 1160 1418 1450

L2 Effective Length 564 624 760 912 1084 1243 1435 1458 1740 1818

Weight (kg/m) 10 Bar 1.8 2.4 5.9 11.4 20.2 36.1 67.8 87.8 126.6 207.6

16 Bar 2.1 3.4 8.6 16.3 29.6 53.6 100.4 129.3 188.7 306.9

NOMINAL DIAMETER 90 110 160

Max Test Pressure (bar) 30 30 30

End Load Joint

Note: This fitting should only be used onpipe and fittings.

Note: Long Radius Bends are available inboth blue and black.Double Socket Bends are also available

Note: All dimensions are in mm unless otherwise stated.

Note: Long Radius Bends are available inboth blue and black.Double Socket Bends are also available

9

NOMINAL DIAMETER 90 110 160 200

L1 Length 333 373 468 554

L2 Spigot Length 207 224 254 292

Short Radius Bend 90°- Single Socket

Long Radius Bend 11.25°- Single Socket

L 1L2

L1

L2

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630

R Radius 300 350 665 1005 1110 1410 1795 1820 2325 2390

L1 Length 360 360 370 404 520 568 610 612 734 745

L2 Effective Length 476 524 564 616 759 828 905 920 1056 1113

Weight (kg/m) 10 Bar 1.6 2.1 4.5 8.1 15.0 24.6 44.5 58.1 79.4 130.7

16 Bar 1.8 2.9 6.5 11.2 21.6 35.9 64.3 83.6 115.8 188.7

Long Radius Bend 22.5°- Single Socket

L 1

L2

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630

R Radius 300 350 665 1005 1110 1410 1795 1820 2325 2390

L1 Length 360 393 432 502 627 706 788 792 961 980

L2 Effective Length 507 557 626 714 866 966 1083 1100 1283 1348

Weight (kg/m) 10 Bar 1.6 2.2 5.0 9.2 17.3 28.5 52.2 67.9 95.2 156.3

16 Bar 1.9 3.1 7.2 12.9 25.2 41.8 76.3 98.7 140.1 228.1

Note: All dimensions are in mm unless otherwise stated.

Note: Long Radius Bends are available inboth blue and black.Double Socket Bends are also available

Note: Long Radius Bends are available inboth blue and black.Double Socket Bends are also available

Note: Double Socketed and Flanged Bendsare also available

10

Note: All dimensions are in mm unless otherwise stated.

NOMINAL DIAMETER 90 110 160 200

L1 Length 666 746 936 1108

L2 Branch Length 333 373 468 554

Equal Tees

NOMINAL DIAMETER 110 160 160 200 200 200

BRANCH DIAMETER 90 90 110 90 110 160

L1 Length 746 936 936 1108 1108 1108

L2 Branch Length 358 403 423 443 463 508

Unequal Tees

Short Radius Bend 45°- Single Socket

L 1

L2

L1

L2

L1

L2

NOMINAL DIAMETER 90 110 160

L1 Length 306 340 421

L2 Spigot Length 207 224 254

Note: Tees with any Spigot, Socket or Flangedcombinations are available

Note: Tees with any Spigot, Socket or Flangedcombinations are available

Note: Double Socketed and Flanged Bendsare also available

11

Socket Flange

NOMINAL DIAMETER 90 110 160 200

L1 Overall Length 291 321 391 459

L2 Flange Thickness 19 20 26 26

NOMINAL DIAMETER 90 110 160 200

L1 Overall Length 263 290 345 405

L2 Flange Thickness 19 20 26 26

Spigot Flange

Reducers

NOMINAL DIAMETER 110 160 200

REDUCING DIAMETER 90 110 160

L1 Effective Length 584 696 812

Double Sockets

NOMINAL DIAMETER 90 110 160 200 250 315

D Insertion Depth Min 140 160 190 210 235 265

S Seal Depth Min 60 75 86 100 115 125

A Outside Diameter Max 135 150 215 260 315 395

A

DS

L1

Note: Backing ring drilled to BS 4504 NP16

Note: Backing ring drilled to BS 4504 NP16

Note: All dimensions are in mm unless otherwise stated.

12

DESIGN

PRESSURE SYSTEMS

The flow chart has been calculatedon the mean bore of pipes of all workingpressure ratings.The exceptionally smoothbore of pipes enables the systemto be hydraulically efficient when used forthe transportation of potable water.

The charts have been prepared using theColebrook-White flow equation todetermine the required pipe dimension andsubsequent loss of head. In this equationthe velocity of flow is related to the pipebore, the kinematic viscosity of water,acceleration due to gravity and thehydraulic roughness of the pipeline.

The Colebrook-White equation:

V = -2√2gDi Log ( Ks + 2.51v )3.7D D√2gDi

where:

V = velocity in metres per second

g = gravitational acceleration(9.81 m/s2)

i = hydraulic gradient

v = kinematic viscosity of fluid(a value of 1.141 x 10-6 m2/s has beenassumed for water at 15°C)

Ks = linear measure of effective roughness(0.003 mm)

D = Mean internal diameter of pipe inmetres

The frictional losses caused by fittings canalso be determined and are approximatelyproportional to the square of the liquidvelocity. Loss of head can be calculatedusing the following formula:

H = Kv2

2g

where:

H = loss of head (m)

v = liquid velocity (m/s)

g = gravitational acceleration(9.81 m/s2)

K = coefficient (dependent on type offitting)

Various values for K are:

11.25° Bend = 0.025

22.5° Bend = 0.05

45° Bend = 0.1

90° Bend = 0.2

Figure 5 8 bar Hydraulic Flow Chart

Hydraulic Design

1000

0.0001 0.001

0.1 0.25 0.5

1.0

2.0

3.0

3.4

4.5

5.7

7.6

0.01 0.1

100

10

1

0.1

Hydraulic Gradient

Rate of Flow : Litres Per Second

160mm

200mm

250mm

315mm

400mm450mm500mm

630mm710mm

Velocity : Metres Per Second

14

Figure 6 10 bar Hydraulic Flow Chart

Hydraulic Design continued

1000

0.0001 0.001

0.1 0.25 0.5

1.0

2.0

3.0

3.4

4.5

5.4

7.6

0.01 0.1

100

10

1

0.1

Hydraulic Gradient

Rate of Flow : Litres Per Second

110mm

160mm

200mm

250mm

315mm

400mm450mm500mm

630mm710mm

Velocity : Metres Per Second

15

Figure 7 12.5 bar Hydraulic Flow Chart

Hydraulic Design continued

1000

0.0001 0.001

0.1 0.25 0.5

1.0

2.0

3.0

3.4

4.5

5.7

7.6

0.01 0.1

100

10

1

0.1

Hydraulic Gradient

Rate of Flow : Litres Per Second

90mm

110mm

160mm

200mm

250mm

315mm

400mm450mm500mm

630mm710mm

0.075

Velocity : Metres Per Second

16

Figure 8 16 bar Hydraulic Flow Chart

Hydraulic Design continued

1000

0.0001 0.001

0.1 0.25 0.5

1.0

2.0

3.0

3.4

4.5

5.7

7.6

0.01 0.1

100

10

1

0.1

Hydraulic Gradient

Rate of Flow : Litres Per Second

90mm

110mm

160mm

200mm

250mm

315mm

400mm450mm500mm

630mm710mm

0.075

Velocity : Metres Per Second

17

All pressure pipelines with push-fit jointingsystems will be subject to separation forces.Allowance should be made toaccommodate the thrust forces developedwhich would otherwise cause jointdeflection, extension or joint separation.

The development of plastics alloyhas enabled significant improvements to bemade in the design of self anchoring orthrust joints which has culminated in thedesign of the End Load Joint.

The new joint eliminates the need for theconstruction of concrete thrust blocks atall locations where thrust forces areencountered:

● Changes of direction (bends)

● Junctions

● Reductions in diameter

● Blank ends or closed valves

● Adjacent pipes

● Limited space

● Steep inclines

● Soft ground or subsidence areas

Thrust forces acting on a pressure pipelinesystem are made up of static thrusts anddynamic thrusts both of which need to becalculated to determine the overall forceacting upon a joint.

Static thrusts are the result of internalpressure and should be based upon themaximum internal pressure. In this instancethe End Load Joints have been designed tomeet 1.5 times the maximum workingpressure plus 25% (i.e. 30 bar).

Static thrusts can be calculated:

● Blank ends and Junctions:= 102 Ae P (kN)

● Bends:= 102 Ae P 2Sin (kN)

Dynamic thrusts are the result of waterflowing in the pipe in the same direction asthe static thrusts. Dynamic thrusts aregenerally of small magnitude at lowvelocities of flow and only becomesignificant if the velocity of flow exceeds 1.5m/sec.

Dynamic thrusts can be calculated:

● Bends:= 2 x10-3 W Ai V

2 Sin (kN)

For design purposes the combined staticand dynamic forces at changes of directionshould be calculated:

● Bends:= (P+0.01V2) 102 Ae 2Sin (kN)

Where

Ai - is the cross sectional area of pipeinternal diameter (m2)

Ae - is the cross sectional area of pipeexternal diameter (m2)

P - is the internal pressure (bar)

W - is the density of the fluid(kg/m3)(1000 kg/m3 for water)

V - is the velocity of flow (m/s)

α - is the bend angle (degree)

Static thrust forces per 1 bar internalpressure can be read from Table 1. Bymultiplying (P + 0.01V2) by the appropriatethrust per bar of internal pressure, thecombined forces can readily be deduced.

End Load Joints are available in sizes 90mmto 160mm.These should be used wherepossible to avoid the use of concrete thrustblocks.This will significantly speed upinstallation time and reduce the overallcosts of the project.

α2

α2

α2

Thrust Restraint

Nominal End Radial Thrust on BendsExternal ThrustDiameter 90° 45° 22.5° 11.25°(mm) k N k N k N k N k N

90 0.64 0.91 0.49 0.25 0.13

110 0.95 1.36 0.73 0.37 0.19

160 2.01 2.87 1.55 0.79 0.40

200 3.14 4.49 2.43 1.24 0.62

250 4.91 7.01 3.80 1.93 0.97

315 7.79 11.13 6.03 3.07 1.54

400 12.57 17.95 9.72 4.95 2.49

450 15.91 22.72 12.30 6.27 3.15

500 19.64 28.05 15.18 7.74 3.89

630 31.18 44.54 24.10 12.29 6.17

710 39.60 56.56 30.61 15.61 7.84

Table 1 Thrust Forces

18

It is important to note that the End LoadJoint is used at both ends of the bend andon all three sockets on equal and unequaltees.This is a minimum requirement andshould the interface resistance between thesoil and pipe not be sufficient the extra EndLoad Joints must be used on pipe jointsbefore and after the thrust area.

Note: Where End Load Joints are used toresist thrust forces the pipeline itself mustdevelop significant resistance to theseforces without allowing the joints to bepulled apart.The resistance is built up at theinterface between the pipe and itssurrounding material.The designer mustcalculate the distance over which this willtake place by comparing the shearresistance between the pipe and surround

with the overall thrust force and calculatesufficient surface area to generate thenecessary resistance.

Concrete thrust blocks will be required forpipe sizes 200mm and above. At thesepoints it is important to note that directcontact between pipe and theconcrete should be avoided. It isrecommended that a polythene sheet isused to protect the pipe and allow minor

movements to occur to reduce the risk ofstress concentrations.

The nature of the ground will determinethe dimensions and ultimate design of theconcrete block.

The load bearing capabilities of the groundmust be determined at the design stage.

Thrust Restraint continued

1 2

3

4

: End Load Joint

: Pipe

: Thrust Force

1 : Gate valve

2 : Equal tee

3 : Reducer

4 : Blank end

5 : 45°Bend

6 : 45°Bend

7 : 90°Bend

8 : Blank end

Key

5

6

7

8

Figure 9 End Load Joint layout Example

This layout example shows the positionwhere End Load Joints for diameters90-160mm should be used. For diametersabove 160mm concrete anchor blocks willneed to be designed and used.

Figure 10 End Load Joint Usage Example

Direction of water flow

Thrust force

Separation force

End LoadJoint

End LoadJoint

Direction of water flow

19

Surge and Fatigue

Daily Hourly Total Cycles 5ºC 10ºC 15ºC 20ºC 25ºC 30ºC Frequency Frequency in 50 years Rating Factor Rating Factor Rating Factor Rating Factor Rating Factor Rating Factor

4 0.2 73,000 0.67 0.72 0.85 1.0 1.14 1.30

24 1.0 438,000 1.14 1.22 1.45 1.7 1.94 2.21

48 2.0 876,000 1.41 1.51 1.79 2.1 2.39 2.73

120 5.0 2,190,000 1.88 2.02 2.38 2.8 3.19 3.64

240 10.0 4,380,000 2.35 2.52 2.98 3.5 3.99 4.55

1200 50.0 22,000,000 3.75 4.03 4.76 5.6 6.38 7.28

Table 2 Recommended Fatigue Re-rating Factors for

Where detailed surge analysis is to becarried out the modulus (E) for may be calculated from the followingformula:E (GPa) = 1.75 x (time in hours)-0.053.

Typical values being:

E = 3.05 GPa for t = 0.1 secondsE = 2.70 GPa for t = 1.0 secondsE = 2.39 GPa for t = 10 seconds

Fatigue

Fatigue usually occurs as a result ofrepeated pressure cycles generally belowthe rated pressure of the pipe.

It is recommended that the designer takesinto account cyclic loading conditions inpipeline design. It is commonly acceptedthat it is the total pressure range (thedifference between max and min) whichdetermines the decrease in lifetime withfatigue.

When designing for fatigue a pipeline should be re-rated to allow for thedecrease in strength as a function ofrepeated cyclic loading. Re-rating factorsare illustrated in Table 2.

Example of use of Fatigue Re-ratingFactors

If for example, it was computed that therewould be 2 cycles/hr of pressures varyingover a range of 8 bar, with watertemperature of 10ºC.Then the pressurerating should be:

● At least bar 12.08 (1.51 x 8) for.

● Therefore a 12.5 bar pipe canbe selected.

Further advice on surge and fatigue can befound in Design Against Surge and FatigueConditions for Thermoplastic Materials. UKWater Industry Information and GuidanceNote IGN 04-37-02.WRc, 1999.

Negative Pressures

It may be possible for a pipeline to besubjected to a vacuum condition.pipes when correctly installed inaccordance with sitework and

bedding recommendations can withstandthe negative pressures associated with a fullvacuum.

Surge and Fatigue

As with other plastics materials it isimportant to consider the effects of surgeand fatigue on at the design stage.

The terms surge and fatigue are often usedcollectively. However, whilst bothphenomena arise from the same events(rapid valve closure, pump shut down, etc)they should be considered separately sincethey describe different effects on the pipematerial.

Surge

Surge is generally regarded as a ‘one off ’event.An isolated occurrence wherepressures may surge to high levels inexcess of the static rating in a very shorttimescale, without causing fatigue problems,(e.g. emergency pump shutdowns).

To establish if a pipeline will resist a surgeevent, the peak surge must be identified.This should be the worst anticipated event(e.g. emergency trip of all pumps).

Surge factors are used to calculate themaximum allowable surge.These surgefactors are dependent upon the pressurerise rate, and can be read from the graph inFigure 11. If the designer is unsure of thepressure rise rate, a worse case scenariocan be assumed and a surge factor of 2applied.

Example of use of Surge Factors

● A pipeline has beendetermined to have an operatingpressure of 6 bar.

● The pressure rise rate was calculatedto be 2 bar/sec and the peak pressurepredicted to be 12 bar.

● From Figure 1 the surge factor forat 2 bar/sec would be 2.25.

Therefore a pipe rated at 8 bar (PN8)static pressure would be capable ofresisting a peak surge pressure of18 bar (8 x 2.25).

● This would be acceptable as the pipecan resist a surge event of 18 bar whenthe surge event in question is 12 bar.

3.5

3.0

2.5

2.0

1.5

1.00.1 1.0 10.0 100.0

Sur

ge F

acto

r

Pressure Rise Rate (bar/sec)

Figure 11 Surge Factors for Thermoplastics Pressure Pipes at 20ºC

20

External Compressive Loads/Temperature De-rating

External Compressive Loads

Under normal operating conditions it is notnecessary to confirm the performance of a

water pressure pipe for resistanceto soil and traffic loadings.

In these conditions the stress resulting fromthe internal pressure greatly outweighs thesoil and traffic load stresses.

However, in certain circumstances wheremains are expected to stand empty for longperiods of time, engineers may wish toconfirm the structural capabilities of thepipe system under soil and traffic loadconditions.

Table 3 acts as a guide to the minimum andmaximum depth that can beinstalled.

The design procedure used as a basis forthe calculation of this table is based uponthe well recognised theory of M G Spangler.

The table is based on a main road trafficloading condition and calculated using amaximum allowable deflection of 6%, for

pipes installed in a granularcohesive soil with moderate compaction.

Temperature De-rating

, as with other plastics materials,should be de-rated when temperaturesexceed 20ºC.Where fluid or ambienttemperatures rise above 20ºC, the pressurerating of the pipe should be reducedproportionally or the service life of thepipe is reduced. A conservative guide usedin the UK Water Industry for many yearsemploys a 2% reduction in pressure ratingfor every 1ºC increase in temperature andshould be used up to a maximumacceptable temperature of 60ºC as shownin Figure 12.

0 5 10 15 20 25 30 35 40 45 50 55 60

0

2

4

6

8

10

12

14

16

18

Internal or Ambient Temperature (ºC)

Pressure (bar)

16 bar

12.5 bar

10 bar

8 bar

Figure 12 Temperature De-rating

NOMINAL DIAMETER 90 110 160 200 250 315 400 450 500 630 710

Narrow Trench Width 0.40 0.45 0.50 0.50 0.55 0.65 0.70 0.75 0.80 0.95 1.05

Depth 8 bar Min – – 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

(metres) Max – – 7.30 7.30 7.30 7.30 7.30 7.30 7.30 7.30 7.30

10 bar Min – 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

Max – 7.60 7.60 7.60 7.60 7.60 7.60 7.60 7.60 7.60 7.60

12.5 bar Min 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

Max 7.90 7.90 7.90 7.90 7.90 7.90 7.90 7.90 7.90 7.90 7.90

16 bar Min 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75

Max 8.50 8.50 8.50 8.50 8.50 8.50 8.50 8.50 8.50 8.50 8.50

Table 3 installation depths

21

Chemical Resistance

Resistance to Corrosion

is resistant to almost all types ofcorrosion, whether chemical or electro-chemical in nature. Since is a nonconductor, galvanitic and electro-chemicaleffects do not occur.

Because is non-metallic, thematerial is completely resistant to all formsof metallic corrosion.Aggressive watersresulting from both high sulphate soils andlow hardness waters will not attack

in any way.

pipes and fittings are also resistantto a wide range of industrial waters andchemicals and will offer advantages in longterm system life and maintenance coststhus giving real benefits in terms of wholelife cost.

Chemical Resistance

The resistance of to the chemicalagents listed below has been drawn fromCP312: Part 1: 1973 ‘General Principlesand Choice of Materials’.

Applications

For suitability and correct design in specificapplications, reference should be made tonational codes of practice. Details may befound in the WRc Materials SelectionManual and PVC-U Manual.

Chemical Concentration Rating at 20°C

EPDM

Acetaldehyde 40% (w/v) soln. + +100% (w/v) soln. O O

Acetic acid 10% (w/v) soln. + +60% (w/v) soln. + Oglacial O +

Acetic anhydride Technically pure – +Acetone Technically pure – +

Up to 10% aqueous – OAdipic acid Saturated aqueous + +Alcoholic spiritsAliphatic hydrocarbons + +Aluminium chloride 10% aqueous + +

Saturated + +Aluminium fluoride + +Aluminium hydroxide + +Aluminium nitrate + +Aluminium oxalate + +Aluminium oxychloride + +Aluminium potassium sulphate (alum) + +Aluminium sulphate 10% aqueous + +

Cold saturated aqueous + +

Ammonia Gaseous technicallypure + +

Ammonia solution Aqueous cold(ammonium hydroxide) saturated + +

Aqueous 10% + +Aqueous Saturated + +

Ammonium carbonate 50% aqueous + +Ammonium chloride Aqueous 10% + +

Aqueous coldsaturated + +

Ammonium ferrous citrate + +Ammonium fluoride 25% – +Ammonium hydrogen difluoride + +Ammonium metaphosphate + +Ammonium nitrate Aqueous 10% + +

Aqueous saturated + +Ammonium orthophosphates + +Ammonium persulphate + +Ammonium sulphate 10% aqueous + +

aqueous saturated + +Ammonium thiocyanate + +Ammonium zinc chloride + +Amyl acetate Technically pure – +Amyl alcohol Technically pure – +Aniline Technically pure – OAniline hydrochloride Aqueous saturated + O

Chemical Concentration Rating at 20°C

EPDM

Anthràquinone + –Anthraquinone sulphonic acid + +Antimony trichloride 90% aqueous + +Aqua regia Dilute + CArsenic acid 80% aqueous + +Aryl sulphonic acids + –

Barium carbonate + +Barium chloride + +Barium hydroxide Aqueous saturated + +Barium sulphate + +Barium sulphide + +Beer Usual commercial + +Benzaldehyde 100% saturated

aqueous – +Benzene Technically pure – CBenzoic acid All aqueous + +Benzyl alcohol Technically pure O OBismuth carbonate + +Borax, see disodium tetraborate All aqueous + +Boric acid All aqueous + +Boron trifluorideBrine + +Bromine Liquid – CBromomethane (methyl bromide) – –Butadiene Technically pure + CButane Technically pure + CButanols Technically pure + +Butyl acetate Technically pure – OButylphenols Technically pure + CButyric acid 20% aq. soln. – –

Calcium carbonate + +Calcium chlorate + +Calcium chloride Saturated

aqueous all + +Calcium hydrogen sulphite + +Calcium hydroxide Aqueous saturated + +Calcium hypochlorite Cold saturated

aqueous + +Calcium nitrate 50% aqueous + +Calcium sulphate + +Calcium sulphide – –Carbon dioxide Technically pure (carbonic acid) anhydrous + +

Technically pure moist + +

Carbon disulphide Technically pure – CCarbon monoxide + +Carbon tetrachloride Technically pure – –

Key + Recommended O Conditionally recommended– Not recommended C Consult Hepworth Support Line

22

Chemical Concentration Rating at 20°C

EPDM

Casein Technically pure + +Chloral hydrate Technically pure + +Chloric acid 10% aqueous + C

20% aqueous + CChlorine, gas 10% dry + +

100% – –10% moist – +

Chlorine water Saturated + +Chloroacetic acid mono Technically pure + +

50% aqueous + +Chlorobenzene Technically pure – –Chloroethane (ethyl chloride) – –

Chloroform Technically pure – –Chloromethane (methyl chloride) Technically pure – –Chlorosulphonic acid Technically pure + CChromic acid Up to 50% aqueous + C

All aqueous + CChromic potassium sulphate (chrome alum) + +Cider Usual commercial + +Citric acid 10% aqueous + +Copper chloride + +Copper cyanide + +Copper fluoride + +Copper nitrate + +Copper sulphate + +Cresols Up to 90% aqueous O CCrotonaldehyde Technically pure – CCyclohexanol Technically pure – –Cyclohexanone Technically pure + +

Detergents (synthetic) Diluted for use + +Developers (photographic) Usual commercial + +Dextrin Usual commercial + CDextrose + +Dibutyl phthalate Technically pure – +Dichlorobenzene Technically pure – –Dichlorodifluoromethane + +Dichloroethane (ethylene dichloride) – –Dichloroethylene Technically pure – –Dichloromethane (methylene chloride) – –

Diesel oil – –Digol (diethylene glycol) + +Dimethylamine Technically pure O –Dioctyl phthalate Technically pure – ODioxane Technically pure – +Dodecanoic acid (lauric acid) + +Dodecanol (lauryl alcohol) + +

Emulsifiers all + +Emulsions (photographic) + +Ethane + +Ethanediol (ethylene glycol) + +Ethanol (ethyl alcohol)† 95%-100% + –

40% (v/v) aq. soln. + +Ethers Technically pure – –Ethyl acetate Technically pure – +Ethyl alcohol Technically pure + +

96%Ethyl butyrate – –Ethyl chloride Technically pure – +Ethyl formate Technically pure – –Ethyl lacate Technically pure – –Ethylene glycol Technically pure + +Ethylene oxide (oxiran) Technically pure – C

liquid

Fatty acids Technically pure + +Ferric chloride + +Ferric nitrate + +Ferric sulphate + +Ferrous chloride + +Ferrous sulphate + +Fertilizer salts Aqueous + +Fixing soln. (photographic) + +

Chemical Concentration Rating at 20°C

EPDM

Fluorine Technically pure O CFluorosilicic acid conc. + +Formaldehyde 40% (w/w) aq. soln. + +Formic acid 3% aq. soln. + +

10% aq. soln. + +25% aq. soln. + +50% aq. soln. – +100% aq. soln. – –

Fructose + +Fruit juice Usual commercial + +Furfuraldehyde (furfural) Technically pure – –

Glucose + +Glycerol + +Glycol + +Glycollic acid 37% Aqueous + OGrape sugar + +

Heptane Technically pure + –Hexadecanol (cetyl alcohol) – –Hydrobromic acid 50% (w/v) aq. soln. + +Hydrochloric acid 5% aqueous + +

10% aqueous + +Up to 30% aqueous + +36% aqueous + +

Hydrocyanic acid 10% (w/v) aq. soln. + +Hydrofluoric acid 4% (w/v) aq. soln. + +

40% (w/v) aq. soln. + C60% (w/v) aq. soln. + Cconc. C C

Hydrogen Technically pure + +Hydrogen bromide anhydrous + +Hydrogen chloride anhydrous + CHydrogen fluoride anhydrous + –Hydrogen peroxide 3% (w/v) aq. soln. + C

10% (w/v) aq. soln. + C30% (w/v) aq. soln. + C90% (w/v) aq. soln. + C

Hydrogen sulphide + +Hydroxylammonium sulphate + CHypochlorous acid + +

Iodine soln. in potassiumiodine – O

Iron salts All aqueous + +Isopropyl alcohol Technically pure + +

Lactic acid 10% (w/v) aq. soln + +100% (w/v) aq. soln. + +

Lanolin Technically pure + CLauric acid Technically pure + +Lauryl alcohol Technically pure + +Lead acetate + +Lead arsenate + +Lead nitrate + +Lead tetraethyl + +Linoleic acid + +Linseed oil + C

Magnesium carbonate + +Magnesium chloride + +Magnesium hydroxide + +Magnesium nitrate + +Magnesium sulphate + +

Maleic acid 25% (w/v) aq. soln. + C50% (w/v) aq. soln. + Cconc. + C

Malic acid 1% Aqueous + CManganese sulphate + +Mercuric chloride + +Mercuric cyanide + +Mercurous nitrate + +Mercury + +Metallic soaps (water soluble) + +Methyl acetate Technically pure – CMethyl bromide Technically pure – C

Key + Recommended O Conditionally recommended– Not recommended C Consult Hepworth Support Line

23

Chemical Concentration Rating at 20°C

EPDM

Methyl chloride Technically pure _ CMethyl ethyl ketone, Technically pure – +Methyl hydrogen sulphate 90% (w/v) aq. soln. + +Methyl sulphate + +Methylated spirits – –Methylcyclohexanone – –Methylene chloride – C Milk Usual commercial + +Mineral oils + +Molasses Usual commercial + +Monochlorobenzene – –

Naphtha + –Naphthalene Technically pure – CNickel chloride Cold saturated + +

aqueousNickel nitrate Technically pure + +

aqueousNickel sulphate Technically pure + +

aqueousNicotonic acid + +Nitric acid 5% (w/v) aq. soln. + +

10% (w/v) aq. soln. + +25% (w/v) aq. soln. + +50% (w/v) aq. soln. – C70% (w/v) aq. soln. – C95% (w/v) aq. soln. – C

Nitrobenzene Technically pure – CNitropropane Technically pure – CNitrous fumes Low, wet & dry + +

Octane + +Oleic acid Technically pure + OOrthophosphoric acid 20% aq. soln. + +

30% aq. soln. + +50% aq. soln. + +95% aq. soln. + –

Oxalic acid Cold saturated + +aqueous

Oxygen All + +Ozone Up to 2% air + +

Cold saturated + +aqueous

Palm oil + CPalmitic acid 10% + CParaffin oil + CPentane + +Perchloric acid 10% + C

70% O CPetroleum + CPetroleum spirit + CPhenol – –Phenylcarbinol Technically pure – –Phenylhydrazine Technically pure – –Phenylhydrazine hydrochloride Aqueous + +Phosgene gas + C

liquid – CPhosphates + +Phosphine + +Phosphoric acid Up to 30% aqueous + C

50% aqueous + C85% aqueous + C

Phosphorus pentoxide Technically pure + +Phosphorus trichloride – –Picric acid 1% (w/w) aq. soln. – –Polyglycol ethers – –Potassium acid sulphate + +

Potassium antimonate + +Potassium bicarbonate + +Potassium bichromate + +Potassium bisulphate + +Potassium borate + +

Potassium bromate Cold saturated + +aqueous

Chemical Concentration Rating at 20°C

EPDM

Potassium bromide All aqueous + +Potassium carbonate + +Potassium chlorate + +Potassium chloride All aqueous + +Potassium chromate Cold saturated + +

aqueousPotassium cuprocyanide + +Potassium cyanide Cold saturated + +

aqueousPotassium dichromate + +Potassium ferricyanide + +Potassium ferrocyanide + +Potassium fluoride + +Potassium hydrogen carbonate + +Potassium hydrogen sulphate + +Potassium hydrogen sulphite + +Potassium hydroxide 1% (w/v) aq. soln. + +

10% (w/v) aq. soln. + +conc. soln. + +

Potassium hypochlorite + +Potassium nitrate 50% aqueous + +Potassium orthophosphates + +Potassium perborate + +Potassium perchlorate 10% soln. + +Potassium permanganate 10% soln. + +

conc. soln. + +Potassium sulphate All aqueous + +Potassium sulphide + +Potassium thiosulphate + +Propane Technically pure + C

liquidTechnically pure + CGas

Propylene oxide Technically pure

Quinol + +

Ramasit Usual commercial + +

Salicylic acid + +Sea water + +Selenic acid +Silver acetate + +Silver cyanide + +Silver nitrate + +Soap solutions (aqueous) + +Sodium acetate All aqueous + +Sodium aluminate + +Sodium antimonate + +Sodium benzoate Cold saturated + +

aqueousSodium bicarbonate Cold saturated + +

aqueousSodium bisulphate 10% aqueous + +Sodium bisulphite All aqueous + +Sodium borateSodium bromide All aqueous + +Sodium carbonate Cold saturated + +

aqueousSodium chlorate All aqueous + +Sodium chloride All aqueous + +Sodium cyanide + +Sodium ferricyanide + +Sodium ferrocyanide + +Sodium fluoride Cold saturated + +

aqueousSodium hydrogen carbonate + +di Sodium hydrogen orthophosphate + +Sodium hydrogen sulphate + +Sodium hydrogen sulphite + +Sodium hydroxide 1% aq. soln. + +

10% aq. soln. + +40% aq. soln. + +

Sodium hydroxide continued conc. + +Sodium hypochlorite 15% available + +

chlorineSodium hyposulphate + +

Key + Recommended O Conditionally recommended– Not recommended C Consult Hepworth Support Line

24

Chemical Concentration Rating at 20°C

EPDM

Sodium metaphosphate – –

Sodium nitrate Cold saturated + +aqueous

Sodium nitrite Cold saturatedaqueous

triSodium orthophosphate – –Sodium perborate – –Sodium peroxide – –Sodium silicate All aqueous + +Sodium sulphate Cold saturated + +

aqueousSodium sulphide Cold saturated + +

aqueousSodium thiosulphate Cold saturated + +

aqueousSoft soap + +Stannic chloride + +Stannous chloride + –Starch Usual commercial + CStearic acid + CSucrose + +Sulphur colloidal + +Sulphur dioxide dry + +

moist – –liquid – –

Sulphur trioxide + +

Sulphuric acid 10% (w/w) aq. soln. + +20% (w/w) aq. soln. + +30% (w/w) aq. soln. + +40% (w/v) aq. soln. + +45% (w/v) aq. soln. + +50% (w/v) aq. soln. + +55% (w/v) aq. soln. + +60% (w/v) aq. soln. + +70% (w/v) aq. soln. + +80% (w/v) aq. soln. – –90% (w/v) aq. soln. – –95% (w/v) aq. soln. – –

Sulphurous acid 10% aq. soln. + C30% aq. soln. + C

Surface active agents all + +Tallow Technically pure + CTannic acid All aqueous + +Tanning extracts Usual + +

Chemical Concentration Rating at 20°C

EPDM

Tartaric acid All aqueous + CTetraethyl lead Technically pure + +Tetrahydrofuran Technically pure – –Tetrahydronaphthalene (tetralin) Technically pure – –Thionyl chloride Technically pure – CToluene Technically pure – CTransformer oil Technically pure + +Tributyl phosphate Technically pure – –Trichloroacetic acid Technically pure O O

50% aqueous + OTrichlorobenzene

– –Trichloroethane – –Trichloroethylene – –Triethanolamine + –Trigol + +Trimethylamine – –Trimethylol propane + +Trisodium phosphate, + +Tritolyl phosphate – –Turpentine Technically pure – –

Urea Up to 30% aqueous + +

Vegetable oils Usual commercial + –Vinegar + +Vinyl acetate monomer – –Vinyl acetate polymer + +

Water Condensed + +Water Distilled deionised + +Water Drinking + +Water Waste without + +

organic solventWetting agents Up to 5% aqueous + +Wines and spirits Usual commercial + +

Xylene Technology pure – CXylenol – C

Zinc Salts + +

Key + Recommended O Conditionally recommended– Not recommended C Consult Hepworth Support Line

25

SITEWORK INSTRUCTIONS

PRESSURE SYSTEMS

Handling and Storage

pipes are lightweight and easy tohandle.This plastics alloy has beendeveloped to overcome many of theproblems previously encountered by othersystems.Although this very tough materialis highly resistant to impact and abuse onsite, good site practice should be followedwhere possible.

Care should be taken to prevent damage tothe pipe body, especially on the jointingsurfaces.The socket of the pipe protectsthe captive sealing ring from damage inmost situations.

Lifting of pipes by mechanical means shouldalways be carried out so that there is nodirect contact between hooks and chainsand the pipe or joint.

Transport

All pipes are delivered with endcaps to ensure that they arrive in the bestpossible condition. Pack details are listed inTable 4.

*450 and 500 diameter pipes have differingnumbers of pipes per pack to achievemaximum pipes per load.

Pipes up to 315mm can easily be carried byhand although on difficult sites contractorsmay wish to use mechanical means.

All pipes should be loaded on lorriescorrectly to prevent damage andsubsequent performance problems.

Storage

Pipe bundles should be stored no morethan 2m high stacked timber to timber.Individual pipes should not exceed 7 layersin height with the width of the bottomlayer no more than 3m wide. Generallystacking heights should be kept to aminimum with adequate surround space forlifting machinery. It is advisable to storedifferent classes and sizes separately.

Exposure to ultra-violet light can discolourthe pipes and for prolonged storageoutdoors a protective opaque cover shouldbe used. Discoloration has a minimal effect

on the mechanical performance of ,however if there is any doubt pleasecontact the technical advisory service.

Pipe dust caps should not be removed untiljointing commences, this will reduce therisk of contamination within the pipe.

Fittings and jointing materials should bestored separately and preferably undercover.

Attention should be paid at all times toavoid theft, vandalism and contamination.Adequate provision should always be madeto safeguard operatives and the public fromaccidents.

Table 4 Pack Quantities✗

Strappedtimberbattens

Additionalsupportbattens

0.7m 2.25m 2.25m 0.8m

2mmax

Nominal Pipes per Packs per Pipes perDiameter Pack Load Load(mm)

90 96 12 1152

110 50 16 800

160 24 16 384

200 20 12 240

250 12 12 144

315 9 8 72

400 9 8 72

450 * * 50

500 * * 50

630 4 8 24

710 4 8 24

27

Jointing

a) The spigot and socket to be joinedshould be carefully examined for anydamage which would impair the jointingprocedure. Particular attention should bepaid to the spigot chamfer and the sealingring.The pipe should be chamfered to adepth of half the wall thickness and at aninclination angle of 15° to the pipe axis. Ifpipes are cut on site they should be cutsquare to the pipe axis with a fine toothedsaw and chamfered to half the pipe wallthickness with a coarse file or Surformtool.The chamfered spigot should be cleanand free from swarf and burrs.The sealingring should be correctly seated in thesocket groove, complete with the insertring.The sealing portion of the ring mustbe free from damage of any sort. Jointscontaining damaged or incorrectly fittedrings must not be used.

b) The spigot insertion depth should bemeasured as the depth from the mouth tothe shoulder of the socket.

Pipes are supplied with the spigot insertiondepth marked on the spigot end.Thespigots of cut pipes should be markedsimilarly using an indelible crayon. If anallowance for expansion is required, (e.g.where changes in operating temperaturesare anticipated), this should be deductedfrom the spigot insertion depth.

c) The mating areas of the spigot andsocket should be thoroughly cleaned.Allgrease, dirt, swarf and other foreign mattershould be removed from the sealing areas.

d) The spigot end and the sealing ringshould be thoroughly lubricated with theHepworth lubricant supplied free of chargewith the pipe.The spigot should belubricated to the full insertion depth andaround its complete circumference, payingparticular attention to the chamfer area.The seal should be lubricated around itscomplete circumference.The guidingprinciple should be to apply a liberalquantity of lubricant and avoid ‘dry’ areason the mating surfaces.

e) Immediately after lubrication, the spigotshould be brought into contact with thesocket.The spigot pipe and parent jointshould be accurately aligned so that theaxes of the pipes are precisely in line.Thespigot should be hand fed into the socketuntil resistance from the inner sealingsection is felt. Correct alignment at thisstage is essential to ensure that the rubbersealing ring is not pinched or torn.

f) Leverage Method: sizes up to nominaldiameter 250mm can normally be jointedby applying leverage with a crow bar at thefollowing socket end.A stout timber shouldbe inserted between the crow bar and thepipe socket to prevent damage to the pipe.The leverage should be applied in a steady,continuous manner until the spigotinsertion depth mark coincides with themouth of the socket being jointed. Nofurther leverage should be applied. If anyundue resistance is felt or the spigotcannot be levered home, the joint shouldbe disassembled and examined todetermine possible causes (e.g. lack oflubrication and pinched or trapped sealingring).The procedure should then berepeated as described previously.

28

g) Jointing Clamps: are available for sizesabove nominal size 200mm and arespecially designed for use with Water Pressure Pipes.These areparticularly useful where bends and teesare to be installed in the pipeline system.

Instructions for using clamps to joint pipesare enclosed with the product.

Adapting to Other Materials

Jointing on to pipes of different materialsor to Imperial PVC-U sizes can easily beachieved with the use of the Viking Johnsonadaptor couplings or the Stanseal range ofcouplings and adaptors.

Jointing to metric PVC-U is simply achievedby using the normal push-fit jointingprocedure.The OD of is identicalto the OD of Metric PVC-U and thereforethe two systems are compatible.

Jointing continued

29

A pipeline operating under internalpressure will generate thrust forces at anychange of direction, reduction in diameter,blank end or closed valve.

Utilising the End Load Joint, timeconsuming and costly methods such aslaying concrete are now avoidable.The EndLoad Joint is a simple method of restrainingmovement at potential thrust areasallowing work to continue quickly withoutextra site equipment and personnel.

End Load Joint Installation

The following procedure ensures that theEnd Load Joint can be installed correctly,quickly and easily in all sizes and allconditions.

1) Undo bolts and disassemble jointready for installation

2) Place ‘C’ clamp around the shoulder ofthe pipe socket.

3) Bolt together ‘C’ clamp to fingertightness.

4) Slide grab ring housing and the grabring onto the pipe spigot. Largestdiameter facing socket.

5) Slide grab ring up to the pipe insertionmark.

6) Clean and lubricate the pipe spigot upto the grab ring.

7) Clean and lubricate the pipe socketand the seal around its completecircumference.

8) Insert pipe spigot into socket asnormal using leverage method jointingclamps. Ensure that the pipe is pushedup to the insertion depth mark.

9) Push grab ring up to socket face. Pushhousing up to and over the grab ring.Locate the bolts through the boltholes. Fit nuts and washers.

10) Fully tighten ‘C’ clamp bolt and thethree restraining bolts. Due to thedesign of the fitting the bolts cannotbe overtightened.

Note: End Load Joints are designed onlyfor use with water pressuresystems. Hepworth cannot accept liability ifused with any other system components.

An End Load Joint installation instructionleaflet is provided in the packaging for easyreference on site. For further informationconcerning the design and location ofthrust restraints refer to the DesignSection in this leaflet.

End Load Joint Installation

30

Deflection and Curvature

Joint Deflection

Delection of the Joint is achievabledue to the compressibility of theelastomeric sealing ring, and deflectionswithin the recommended limits will notaffect the performance of the seal.

The maximum deflection of the jointshould be limited to one degree (1º).Any greater deflection than this may cause‘binding’ of the socket and spigot whichcould result in high stresses being imposedwithin the joint.

A one degree deflection on a 6 metre piperepresents approximately 100mm change indirection (A) as shown in Figure 13.

Both the joint deflection and pipecurvature methods of achieving longitudinalbending should be strictly limited to therecommendations given in this guide, andpreference given to the use of pre-formed bends.

Pipe CurvatureGeneral

One of the practical features of isits ability to bend when cold.The benefitsof this cold bending property can beutilised during installation and when thepipe is in service.

During installation pipes can be cold bentas a means of overcoming certaintopographical and man-made obstructionswithout recourse to the use of purpose-made bends.The minimum radius for thecold bending of is 150 times themaximum mean outside diameter of thepipe.The results of which are illustrated inTable 5.

During service the pipe has an inbuiltability to take up ground movementscaused by subsidence or differentialsettlement without undue stresses beingincurred on the pipe wall.

Practical Considerations

It can be shown that as the pipe diameterincreases the force required to affect thebending radius quoted increases.

The force required can place practicallimitations on the maximum pipe diameterconsidered suitable for bending duringinstallation. It is recommended that thecold bending of be limited to anominal diameter of 200mm.To achievedeviation in-line on larger diameters

pre-formed bends should be used.Figure 14 illustrates the maximumcurvature permissible on a 6 metre

pipe.

The following points must beconsidered when cold bending:

● Cold bending should not be attemptedat ambient temperatures less than 5ºC.

● The trailing socket must be securelyfixed in position before the pipe isbent.

● On no account must the trailing socketbe subject to angular deflection andhence additional stresses.

● Bending should be carried out manuallywherever possible.

● If mechanical pulling devices are usedthe pipe must be adequately protectedfrom damage. Metal chains, slings, hooksor straps must not come into directcontact with the pipe.

● The pipe must be securely fixed in itsradiused position before layingproceeds. pipe has a ‘memory’and will re-straighten itself if notsecured.

● Every precaution shall be taken duringthe drawing operation to ensure thesafety of site personnel.

A

1°

6m

Figure 13 Angular deflection of a single pipe joint

Table 5 Pipe Curvature

Nominal Dia, Ø A

(mm) (m)

90 1.30

110 1.10

160 0.75

200 0.60

6m

A

Ø

Figure 14 Maximum curvature permissible on a 6m pipe

31

Deflection and Curvature continued

pipes, Sardinia

Water Services Connections to

has been extensively testedsuccessfully with various tapping tees underboth laboratory and site conditions,however, as with all tappings care must betaken since blunt cutters and/or badlyaligned tappings have been a significant causeof pipe failures in the past, particularly whencarried out under pressure.

The recommended method of effecting aservice connection is by the use of apurpose-made tapping saddle tee, of plastic

or metal construction, strapped around thepipe.The saddle tee incorporates a self-tapping ferrule, which ensures that thecutter is sharp and geometrically correct,and used only once. On withdrawal, thecoupon of pipe is held within the cuttinghead, which may prove useful as atemporary closing device should such anaction be required.

The design of the cutter is important thecutter must be fluted, solid cutters arenot suitable for cutting .

On clamping the saddle tee to the pipe, careshould be taken that sufficient compressionof the sealing gland is achieved to ensure awatertight seal, but without over-tightening.

The outlet to the tapping tee should bespecified as to direction in relation to themain pipe, although swivel ferrules areavailable.The outlet union required willdepend upon the service pipe material to beused.

The size of any one tapping should notexceed one quarter of the outside diameterof the pipe up to a maximum of 37mm.Tapping machines are available for largerdiameters, but this would only be

acceptable, in a special case, on a largediameter main.

Varying amounts of swarf are generatedwhen cutting depending upon thediameter of the cutter and the wallthickness of the pipe, this swarf must becontained within the body of the cutter.Larger diameters and thicker walled pipestherefore require longer cutters.

The grooves of the flutes need to be fairlyshort, again to retain the swarf.

The separation distance between twoadjacent tappings should be not less thanthan 500mm or five times the main pipediameter, whichever is the greater.

At all service connections, extra care withsoil compaction is necessary to preventexcessive bending and shear stresses beingcreated by subsequent ground or pipemovement.

Manufacturers that have been tested oninclude:-

Barber, Booth, Plasson,Talbot and Waterfit.

32

The system can be jointed topipes, fittings and valves of differentmaterials through the use of flanged fittingsin the range.

Most of the standard fittings within therange are available with flanges or

a combination of flange, socket or spigots.

Flange Bolting Recommendations

● Mating surfaces must be clean andundamaged.

● Use a single rubber gasket to BS 2494of the correct size.

● No jointing compound is needed tomake the joint.

● Flange joints should be assembledbefore other joints on the pipeline.

● The mating surfaces must be aligned towithin 5mm before bolting.

● Use undamaged nuts, bolts and flatwashers of the correctsize.

● The gasket must be correctly alignedbefore bolting.

● The nuts and bolts are to be tightenedusing a torque wrench to therecommended torque in a diagonallyopposite sequence as illustrated,progressively from finger tight to finaltorque; e.g.5% 20% 50%of final torque of final torque of final torque

75% 100%of final torque of final torque

● On 200mm and above it isrecommended two operators shouldwork simultaneously on diametricallyopposite bolts.

● Check the final torque of bolts afterone hour when they have been allowedto relax.

Adapting to Other Materials

Jointing on to pipes of different materials orto Imperial PVC-U sizes can easily beachieved with the use of the Viking Johnsonadaptor couplings or the Stanseal range ofcouplings and adaptors.

Jointing to metric PVC-U is simply achievedby using the normal push-fit jointingprocedure.The OD of is identicalto the OD of Metric PVC-U and thereforethe two systems are compatible.

Flange Jointing

8 1

54

3

72

6

Size (mm) Torque (Nm)

90 40

110 45

160 60

200 75

Table 6 Bolt Torques

33

Inspection and Testing

When the system has been fully installedall pipework and fittings should be visuallyinspected and hydraulically tested.Where practical, joints should be leftexposed until hydraulic testing has beensuccessfully completed.

Visual Inspection

The system should be visually inspected toensure that the correct installationprocedures have been followed and thatpipes and fittings are adequately supportedand restrained in the prescribed manner.

Hydraulic Testing

The PE Type 2 test method is used.

pipelines should be tested inreasonable lengths, appropriate to thediameter and site conditions. Pipelineslonger than 1 km may require testing insections.

a) Thrust ForcesDuring installation the pipeline should havebeen suitably anchored to resist thrust atchanges of direction and at fixed points suchas branches and hydrant connections.Testingshould not take place until anyin-situ concrete has attained its requiredstrength (normally a minimum of 7 daysafter pouring).

b) Charging the MainThe test section should be isolated, wherenecessary, from the rest of the system.A blank end connection, drilled and tappedfor test equipment, should be installed on asuitable face flange or incorporated bymeans of a VJ flange-adapter or similar.

All blank ends on the system should beadequately strutted to resist the thrustdeveloped as a result of the internalpressure. Testing should not be carriedout against closed valves.

The system should be filled from its lowestpoint to encourage expulsion of air as thepipeline fills.Adequate air releasemechanisms should be sited at high points.

c) PressurisingAfter charging, the system should be left tostabilise for at least 2 – 3 hours.The recommended test pressure is 1.5times the working pressure of the system,up to a maximum of 1.5 times the rating ofthe lowest rated component in the system.The test pressure should be applied slowlyand steadily.The pressure rise should bemonitored and recorded. Upon reaching thedesired test pressure, the pipeline should beisolated and the pressure allowed to decay.

d) Pressure Test AnalysisThe use of a data logger is stronglyrecommended.

The time taken to reach pressure is tL.Takea pressure reading P1 at t1, where t1 = tL.Take a second reading P2 at t2, wheret2 = 7tL.

To allow for the stress relaxation behaviourof the material, a correction factormust be applied to the times, as follows:

t1c = t1 + 0.4tL, t2c = t2 + 0.4tL

The slope of the pressure decay curvebetween t1 and t2 is calculated as the ratio:

n1 =log P1 – log P2

log t2c – log t1c

For a sound main, the ratio n1 should be0.01 – 0.085 for pipes without constraintand0.01 – 0.05 for pipes with compactedbackfill.

If the values are significantly lower than this,then there may be too much air trapped inthe pipeline.

Take a further reading P3 at t3 where t3 is atleast 15tL.Again calculate the corrected timet3c = t3 + 0.4tL.

The slope of the pressure decay curvebetween t2 and t3 is calculated as the ratio:

n2 =log P2 – log P3

log t3c – log t2c

A value of n2 in excess of 0.1 for a pipewithout constraint, or 0.06 for a pipe withconstraint, indicates the presence of a leak.

The sensitivity of the test can be increasedby extending the length of t3.

If, at any stage the presence of anunacceptable leak is indicated, it is advisableto check all mechanical fittings, beforevisually inspecting the pipe joints.Anydefects revealed should be rectified and thetest repeated, once sufficient time haselapsed to allow the pipeline to recoverfrom the previously imposed conditions,typically 5 times the previous test period.On completion of testing, the remainingpressure should be slowly released.

A more detailed copy of this test method isavailable on request.

Commissioning

Following a successful pressure test themain should be cleaned, sterilised andbrought into service as soon as possible.Thefollowing procedures should be completed:

● Cleaning by flushing or swabbing themain

● Filling and disinfecting

● Emptying with neutralisation

● Refilling the main

● Bacteriological sampling

● Acceptance certification

● Introduction of the main into service

For further information please refer to theWRc manual for PVC Pressure Pipe SystemsJuly 1994.

Installation Above Ground

Protection is required against exposure toultra-violet light, cold temperatures andimpact damage.

becomes less resistant to impact atsub-zero temperatures.The pipe should beprotected accordingly in exposedconditions.Waterproof lagging should beemployed to protect the pipe. Freezingconditions are possibly the most seriousproblem and provision to drain down thesystem at a low point should be employed.

Thermal Movement

In common with a number of engineeringmaterials will expand and/orcontract under the influence of variations inpipe and ambient temperatures.Thecoefficient of thermal expansion/contractionof is 7.0 x 10-5 per ºC. Due accountshould be taken of possible expansion orcontraction when installing pipeswhich will be subject to variations intemperature either immediately followinginstallation or in their service lifetime.

Thermal expansion and contraction shouldbe allowed for and sufficient freedom ofmovement allowed for at brackets.

Change in length can be calculated from theformula:∆L = α L ∆T

∆L = Change in length (mm)α = Coefficient of linear expansion

(0.07mm/m/ºC)L = Original length of pipe (m)∆T = Change in temperature (ºC)

Expansion can normally be accommodatedwithin the Integral Socket withoutrecourse to special fittings or pipearrangements.

Pipe Support Brackets

These should be as wide as practical,without sharp edges, but a minimum of75mm. Plastic coating is ideal, otherwise,rubber or another suitable membrane isbetter than bare metal.

Support Centres

In many non-buried situations the needarises to provide pipe supports to ensurethat the weight of the pipe and its contentsare adequately supported.

The recommended maximum supportspacings are given in Table 7. For verticalpipe runs the values below should beincreased by 30%.

Table 7 maximum supportspacings

Inspection and Testing/Installation Above Ground

Nominal P N P NSize 8 & 10 12.5 & 16(mm)

90 1.4 1.5

110 1.5 1.7

160 1.8 2.1

200 2.1 2.5

250 2.4 2.9

315 2.6 3.1

400 3.1 3.7

450 3.4 3.7

500 3.7 3.7

630 3.7 3.7

710 3.7 3.7

34

Trench Work

The line and level of the pipe and burieddepth of the pipeline, will have beenpredetermined at the design stage.

The trench should not be excavated toofar in advance of pipe laying and should bebackfilled as soon as possible, however,joints should be left exposed until testinghas been successfully completed.

The width of the trench at ground level willdepend on the type of subsoil and burieddepth of the pipeline.The minimum widthof the trench at the pipe springing lineshould be as narrow as practicable but notless than the pipe diameter plus 300mm.The maximum width of the trench at thecrown of the pipe must not exceed thepipe diameter plus 600mm.

Trench Information

a) Direct LayingIf the pipe is to be laid directly onto thetrench bottom make sure that the trenchformation is composed of stable, uniform,fine-grained soil, with no boulders, bricksor rocks which might cause point-loadingon the pipe.

When laying the pipe directly, the trenchformation should be trimmed to an evenfinish which will provide continuoussupport to the pipe.

Additional excavation will be required atthe position of the pipe sockets to ensureproper joint assembly and pipe support.

b) Pipe Laying on BeddingIf the formation is unsuitable for directlaying the trench will need to be excavatedto a further depth of a minimum of 100mmbelow the underside of the pipe.

This should be made up with a suitablebedding material. In extreme conditionssuch as waterlogged or unstable ground itmay be necessary to increase the thicknessof the bedding material.

Pipelines laid through rock should alwaysbe laid on a minimum of 100mm bed ofsuitable bedding materials.

Bedding Material

The bedding material selected may beavailable from excavated trench material ormay need to be imported from anothersource.The material should be granular innature, free from large stones or debrisand preferably fine grained. Materials suchas clay or hard chalk, which will break upwhen wetted, should not be used. Suitablematerials are free draining coarse sand andnominal single size gravel with rounded orangular particles. Gravels should be nominalsingle size 10mm or 5 to 10mm graded,which have good self compactingproperties.

The bedding material should be placedcarefully in the trench and properlycompacted by hand to ensure a soundcontinuous bed for the pipes. Particularattention should be paid to the socketholes to ensure the correct placement andcompaction of bedding material in thisarea. Bricks or other forms of temporarypipe support should never be left in thetrench.

To test the suitability of selected as-duggranular bedding and sidefill materialrepresentative samples should be evaluatedusing the Compaction Fraction Test,detailed over:

Bedding Requirements

Top soil/road surface

Normal backfill

Selected backfill

Suitable beddingmaterial

No wider than pipe diameterplus 600mm at pipe crown

Not less than pipe diameterplus 300mm

Selected backfill to a minimum of 100mmabove pipe crown

100mm min

Not less than750mm cover

Place 200mm of excavated material on top of 100mm of selected backfill before using mechanical compactors

Figure 15 Recommended trench detail

35

Apparatus

1. Open-ended cylinderApproximately 250mm long and 150mm(+10mm-5mm) internal diameter (160mmdiameter pipe is suitable).

2. Metal rammerMetal rammer with striking faceapproximately 40mm diameter andweighing 0.8kg to 1.3kg.

3. Rule

Method

Obtain a representative sample more thansufficient to fill the cylinder (about 10kg).To obtain this sample, heap about 50kg ofthe proposed material on to a cleansurface and divide it with a spade down themiddle into two halves. Divide one of theseand repeat this procedure until therequired mass of sample is left. It isimportant that the moisture content of thesample should not differ from the bulk ofthe material at the time of its use in thetrench.

Place the cylinder on a firm flat surface andgently pour the sample material onto it,loosely and without tamping. Strike off thetop surface level with top of cylinder andremove all surplus spilled material. Lift thecylinder up clear of its contents and placeon a fresh area of flat surface. Place aboutone quarter of the material back in thecylinder and tamp vigorously until nofurther compaction can be obtained.Repeat with the second quarter, tamping asbefore, and so on for the third and fourthquarters, tamping the final surface as levelas possible.

Determination of CompactionFraction

The Compaction Fraction is determined asfollows:

Measure from the top of the cylinder tothe surface of the compacted material.Thisdistance in millimetres divided by theheight of the cylinder gives the compactionof the material under test.

Suitability of Compaction Fraction

Suitability of Compaction Fraction for useare:

Compaction Fraction Suitability for use0.15 or less . . . . . . . . .Material suitable

0.15 - 0.3 . . . . . . . . . . .Material suitablebut requires extracare in compaction.Not suitable if thepipe is subject towaterloggedconditions afterlaying.

Over 0.3 . . . . . . . . . . .Material unsuitable

Further information on bedding and sidefillmaterials can be found in:

IGN 4-08-01 Issue 4: Imported Granularand Selected As-Dug Bedding and SidefillMaterials for Buried piplines.

WIS 4-08-02 Issue 1: Specification forBedding and Sidefill Materials for BuriedPipelines.

Compaction Fraction Testing

36

Jacking Pipe

PRESSURE SYSTEMS

Product Data

NOMINAL INTERNAL DIAMETER M M 100 150 200 250 300 400 450 500 600

Working Pressure Bar P 10 10 10 10 10 10 10 10 10

Outside Diameter Min m m O D 230.0 330.0 380.0 430.0 530.0 630.0 780.0 880.0 980.0

Max m m O D 250.0 350.0 400.0 450.0 550.0 650.0 800.0 900.0 1000.0

Inside Diameter Min m m ID1 106.4 154.9 193.5 242.1 305.1 387.6 436.0 484.5 610.5

Max m m ID1 107.3 156.1 195.0 243.9 307.2 389.9 438.5 487.1 613.5

Plastic Outside Diameter Min m m O D1 110.0 160.0 200.0 250.0 315.0 400.0 450.0 500.0 630.0

Max m m O D1 110.4 160.5 200.6 250.8 316.0 401.0 451.0 501.0 631.0

Plastic Wall Thickness Min m m t 3.1 4.4 5.6 6.9 8.8 11.1 12.5 13.9 17.5

Max m m t 3.6 5.1 6.5 7.9 9.9 12.4 14.0 15.5 19.5

Plastic Socket Outside Diameter m m A 150.0 215.0 260.0 315.0 395.0 500.0 560.0 610.0 770.0

Minimum Concrete Thickness m m a 40.0 57.5 60.0 57.5 67.5 65.0 110.0 135.0 105.0

Overall Wall Thickness Min m m T 122.7 173.9 185.0 186.1 222.8 240.1 341.5 392.9 366.5

Max m m T 143.6 195.1 206.5 207.9 244.9 262.4 364.0 415.5 389.5

Weight kg/m – 96.7 186.2 231.8 272.6 397.9 517.4 853.5 1090.9 1194.2

Allowable Jacking Load No deflection Tonne – 65 174 216 222 348 390 1004 1466 1160

0.5 deflection Tonne – 65 130 134 112 154 153 319 433 339

Jacking Pressure Pipe - 10 Bar Single Socket

JACKING

Concrete

ChipboardRing

PressurePipe

O D

T

A

O D1

ID

t

a

Key:A = Plastic socket outside diametera = Minimum concrete thicknessO D1= Pressure pipe outside diameterO D = Overall outside diameter

ID1 = Inside diametert = Plastic wall thicknessT = Overall wall thickness

Jacking Pressure Pipe

Figure 16

Jacking Pressure Pipe

As part of the company’s unparalleledcommitment to the innovation of newproducts, Hepworth offer a range of pipesfor use in applications using trenchlesstechnology.This new range enables highperformance pressure pipes to be installedin congested or inaccessible sites in a singleoperation.

This is a unique combination of materialsand technology.The pipe consists of acomposite wall structure comprising

pressure pipe on the internal faceand a concrete wall on the outside face.The concrete part of the wall is designedto accommodate the jacking stresses andthe the hoop stress created byinternal pressure from the liquid being

transported through the completedpipeline.

Jacking Pipes are designed toprovide a finished pressure pipeline of 10or 16 bar rating in a single drive installationprocess.The pipes are available in lengthsfrom 1 m upwards.Typical lengths are1.2 m, 1.5 m and 2.0 m.

Note: All dimensions are in mm unless otherwise stated.

NOMINAL INTERNAL DIAMETER M M 100 150 200 250 300 400 450 500 600

Working Pressure Bar P 16 16 16 16 16 16 16 16 16

Outside Diameter Min m m O D 230.0 330.0 380.0 430.0 530.0 630.0 780.0 880.0 980.0

Max m m O D 250.0 350.0 400.0 450.0 550.0 650.0 800.0 900.0 1000.0

Inside Diameter Min m m ID1 104.4 152.0 190.2 237.8 299.6 380.5 428.1 475.7 599.6

Max m m ID1 105.6 153.5 191.9 239.9 302.0 383.5 431.3 479.1 603.5

Plastic Outside Diameter Min m m O D1 110.0 160.0 200.0 250.0 315.0 400.0 450.0 500.0 630.0

Max m m O D1 110.4 160.5 200.6 250.8 316.0 401.0 451.0 501.0 631.0

Plastic Wall Thickness Min m m A 4.8 7.0 8.7 10.9 14.0 17.5 19.2 21.9 27.5

Max m m a 5.6 8.0 9.8 12.2 15.4 19.5 21.9 24.3 30.4

Plastic Socket Outside Diameter m m t 150.0 215.0 260.0 315.0 395.0 500.0 560.0 610.0 770.0

Minimum Concrete Thickness m m t 40.0 57.5 60.0 57.5 67.5 65.0 110.0 135.0 105.0

Overall Wall Thickness Min m m T 124.4 176.5 188.1 190.1 228.0 246.5 348.7 400.9 376.5

Max m m T 145.6 198.0 209.8 212.2 250.4 269.5 371.9 424.3 400.4

Weight kg/m – 97.6 188.0 234.6 277.1 404.2 529.1 868.4 1109.3 1223.4

Allowable Jacking Load No deflection Tonne – 65 174 216 222 348 390 1004 1466 1160

0.5 deflection Tonne – 65 130 134 112 154 153 319 433 339

Jacking Pressure Pipe - 16 Bar Single Socket

38

WATER PRESSURE SYSTEMSGENERAL INFORMATION

PRESSURE SYSTEMS

Conversion Chart

LENGTH metre m

in 2.54 x 10-2

ft 3.048 x 10-1

yd 9.144 x 10-1

mile 1.60934 x 103

mm 10-3

cm 10-2

AREA metre2 m2

in2 6.4516 x 10-4

ft2 9.29030 x 10-2

yd2 8.36127 x 10-1

acre 4.04686 x 103

mile2 2.58999 x 106

mm2 10-6

cm2 10-4

dm2 10-2

km2 106

VOLUME metre3 m3

in3 1.63871 x 10-5

ft3 2.83168 x 10-2

yd3 7.64555 x 10-1

gal (UK) 4.54609 x 10-3

gal (US) 3.78543 x 10-3

barrel (US) 1.58988 x 10-1

mm3 10-9

cm3 10-6

dm3 10-3

litre 1.00003 x 10-3

MASS kilogram kg

grain 6.47989 x 10-5

oz 2.83495 x 10-2

lb 4.53592 x 10-1

cwt 5.08023 x 101

ton (UK Long) 1.01605 x 103

ton (US Short) 9.07185 x 102

µg 10-9

mg 10-6

g 10-3

tonne (metric) 103

VELOCITY m/s

in/s 2.54 x 10-2

ft/s 3.048 x 10-1

ft/min 5.08 x 10-3

mph 4.4704 x 10-1

cm/s 10-2

km/h 2.77778 x 10-1

ACCELERATION m/s2

ft/s2 3.048 x 10-1

cm/s2 10-2

FLOW volume m3/s

ft3/s 2.83168 x 10-2

cfm 4.71947 x 10-4

gal/s 4.54609 x 10-3

gal/h 1.26280 x 10-6

litre/s 1.00003 x 10-3

litre/h 2.77786 x 10-7

m3/min 1.66667 x 10-2

m3/h 2.77778 x 10-4

FLOW mass kg/s

lb/s 4.53592 x 10-1

lb/h 1.25998 x 10-4

ton/h 2.82236 x 10-1

kg/h 2.77778 x 10-4

DENSITY kg/m3

lb/in3 2.76799 x 104

lb/ft3 1.60185 x 101

lb/gal 9.97763 x 101

slug/ft3 5.15379 x 102

ton/yd3 1.32894 x 103

g/cm3 103

g/litre 9.99972 x 10-1

g/m3 10-3

FORCE Newton (N) kg-m/s2

lb-force 4.44822

poundal 1.38255 x 10-1

dyne 10-5

gm-force 9.80665 x 10-3

kg-force 9.80665

joule/cm 102

PRESSURE Pascal (P) kg/m-s2 N/m2

in-H2O 2.49089 x 102

ft-H2O 2.98907 x 103

in-Hg 3.38639 x 103

psi (lbf/in2) 6.89476 x 103

lbf/ft2 4.78803 x 101

tonf/in2 1.54443 x 107

tonf/ft2 1.07252 x 105

poundal/in2 2.14296 x 102

poundal/ft2 1.48816

mm H2O (kgf/m2) 9.80665

cm H2O 9.80665 x 101

mm Hg (torr) 1.33322 x 102

cm Hg 1.33322 x 103

dyne/cm 10-1

atmosphere 1.01325 x 105

millibar 102

bar 105

Newton/mm2 106

Newton/cm2 104

VISCOSITY dynamic kg/ms

lb/ft s 1.48816

lb/ft h 4.13378 x 10-4

centipoise 10-3

poise 10-1

VISCOSITY kinematic m2/s

ft2/s 9.29030 x 10-2

ft2/h 2.58064 x 10-5

cm2/s 10-4

centistokes 10-6

Stoke 10-4

m2/h 277778 x 10-4

To convert into SI units multiply by the given factor.To convert SI to English/Metric divide by the factor.

40

WATER PRESSURE SYSTEMSINDEX

PRESSURE SYSTEMS

WATER PRESSURE SYSTEMSSUPPLY AND ADVISORY GUIDE

PRESSURE SYSTEMS

PLUMBING HO TLINESPRESSURE PIPE A N D D U C T

ORDERS & ENQUIRIES Tel: 01709 856402 Fax: 01709 856403

ABOVE G R O U N D PLASTICS A N D Hep2O

ORDERS & ENQUIRIES Tel: 01709 856400 Fax: 01709 856401

TECHNICAL SUPPORT Tel: 01709 856406 Fax: 01709 856407

LITERATURE SERVICE Tel: 01709 856408 Fax: 01709 856409

OFFICE HOURS

For all orders and enquiries:

8.30am-5.00pm.

Answerphones operate outside these times.