PURPOSE

To apprise management on recommendation on material selection

for new 7 MGD Water line.

SEQUENCE

Material Used World Wide

Market Share of Different Materials

Key factors for Selecting Material

Consideration for Hydraulic Design

Comparison of Hydraulic Design

Mechanical Design Consideration

Consideration for Buried Pipeline Design

World Wide Experiences and Recommendations

Summing up

Conclusions

Recommendation

MATERIAL USED WORLD WIDE

Material Used for Water Line

Steel

Stainless Steel

GRP

ConcreteDuctile Iron

Poly Ethylene

Poly Vinyl Chloride

MARKET SHARE OF DIFFERENT MATERIAL

PVC7% Poly-

ethylene19%

Ductile Iron38%

Steel15%

GRP8%

Concrete13%

Large Diameter Pipe Material used in Europe(> 300 mm)

MARKET SHARE OF DIFFERENT MATERIAL

PVC24%

Polyethylene54%

Concrete0%

Ductile Iron17%

Steel3% GRP

1%

Small Diameter Pipe Material used in Europe (90 ~ 299 mm)

KEY FACTORS FOR SELECTING MATERIAL

Diameter

Buried Pipe Design

Burst Pressure

Hydraulic Design

Possibility of Water Hammer

Operational

& Installation

Issues

Failure Mode & Failure rates

World Wide Experience

CONSIDERATION FOR HYDRAULIC DESIGN

Inter Diameter Absolute Roughness

Hazen William Coefficient

Manning’s Friction Factor

COMPARISON – INTERNAL DIAMETERS

GRP 31.62 “

Ductile Iron 31.32 “

Concrete lined

Ductile Iron 31.07”

Concrete 30.00”

Carbon Steel

29.376”

PVC29.29”

PE 25.83“

COMPARISON - ABSOLUTE ROUGHNESS

Cement Lined

Ductile Iron

Uncoated Steel

PVC

HDPE

GRP

0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

Absolute roughness, k ( mm)

Low

er

Abso

lute

ro

ugh

ness

COMPARSION-HAZEN WILLIAM FRICTION COEFFICIENT

Ductile Iron

Concrete

Steel

PVC

Polyethylene

134 136 138 140 142 144 146 148 150 152

Hazen-William Friction Coefficient

Hazen Williams' Equation: hF = L *

(Q/C)1.852 D4.87

Ductile Iron

Concrete

Steel

PVC

Polyethylene

0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016

Manning’s Friction Factor

Lo

wer

Man

nin

g F

acto

r

COMPARSION-MANNING’S FRICTION COEFFICIENT

COMPARSION-HYDRAULLIC DESIGN

Material PVC DI PE Concrete GRP Steel Concrete Lined

Flow MGD 8.3 9.07 5.02 6.98 10.77 7.78 7.04

Manning Friction Factor mm 0.011 0.012 0.009 0.014 0.01 0.012 0.013

Hazen-Williams Coefficient

150 140 150 140 150 150 140

Outer Diameter mm 812.8 812.8 762 977.9 813.0 762 762

Inner Diameter mm 743.96 792.98 615.16 762.0 790.14 746.15 743.15

Effective Elevation m 9.04 9.04 9.04 9.04 9.04 9.04 9.04

Required Slope m/m 0.001 0.001 0.001 0.001 0.001 0.001 0.001

PVC are not available in 30” size.

SUMMING UP HYDRAULIC CONSIDERATIONS

All materials are acceptable except Poly ethylene, for which larger

diameter pipe will be required to ensure 7.0 MGD water flow.

PVC pipe of 30” diameter are not available for water mains.

Additionally, all fitting of carbon steel and ductile iron have to be used

with PVC pipe. Therefore, the benefit of utilizing PVC due to hydraulic

reasons diminishes in our case.

Hydraulically, materials are prioritized as :

GRP

Ductile Iron

PVC

Carbon SteelCarbon Steel

Concrete lined

Concrete

PE

MECHANICAL DESIGN CONSIDERATION

Tensile Strength

Yield Strength

Pipe Stiffness

Burst Pressure

Impact Strength

Abrasion Resistance

Surge Pressure

Corrosion Consideration

Temperature De-rating

Failure rates

Ductile Iron

Carbon Steel

PVC Poly Ethylene

Concrete1000

11000

21000

31000

41000

51000

61000Yield Strength in psi

Ductile Iron

Carbon Steel

PE PVC GRP0

20000

40000

60000

80000

100000

120000

140000

160000

180000

200000 Stiffness lb-in

0

200

400

600

800

1000

1200

1400

1600Burst Pressure psi

Ductile Iron

Carbon Steel

GRP PVC Poly Eth-

ylene

Concrete

1000

11000

21000

31000

41000

51000

61000

71000Tensile Strength in psi

Ductile Iron Carbon Steel

Stainless Steel

PVC PE GRP Concrete0

100

200

300

400

500

600

700Abrasion Resistance (Wet Sand Test)

Carbon Steel-New

Carbon Steel Old

Ductile Iron

Stainless Steel

PVC GRP PE Concrete

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6 Corrosion Resistance E

lect

rod

e P

ote

nti

al

V

MO

RE N

EG

ATIV

E M

OR

E

AC

TIV

E

LESS

ER

VA

LU

E

HIG

HER

RES

ISTA

NT

Ductile Iron Carbon Steel

PVC PE GRP Concrete0

10

20

30

40

50

60

Impact Strength~ Charpy Notch TestL

b f

t/in

.

Ductile Iron Steel PVC PE Concrete GRP0

50

100

150

200

250

300

350Leakage Acceptance Criteria

Ga

l/in

-dia

/mile

/da

y

80 90 100 110 120 130 140

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

PVC

PE

Carbon Steel

Ductile Iron

Concrete

GRP

PVCPECarbon SteelDuctile IronConcreteGRP

Temperature -0F

De-r

ati

ng

Facto

r

PVC Pipe rating at 50 0C 60 psi

HDPE pipe rating at 50 0C 94.5 psi

FAILURE RATES

UKWIR Water Mains National Failure Database

0

5

10

15

20

25

30

35

40

1995 1996 1997 1998 1999 2000 2001 2002 2003 Average

Year

Fai

lure

s p

er 1

00km

per

yea

r

Iron

Asbestos Cement

PVC

Ductile Iron

PE© Bodycote PDL

COMMON FAILURE MODES

SteelCement Lined

Ductile Iron Cement Lined PVC PE GRP

Piece Blown Out -

Perforation -

Longitudinal Split - - - -

Pipe Wall Rupture - - -

PIECE BLOWN OUT

PERFORATION

LONGITUDINAL SPLIT

PVC Ductile Iron

PVC

PVCPECarbon Steel

PIPE WALL RUPTURE

LEAKING JOINTMANUFACTURING

DEFECTFRACTURE

Glass Reinforced Plastics Carbon Steel

PVCPVC PVC

COMPARISON-PIPE JOINING METHOD

PVC PIPE BELL AND SPIGOT JOINT

PVC FUSION WELDING

PE FUSION WELDING

GRP BUTT & WRAP JOINT

PVC SOLVENT CEMENTING

GRP BELL & SPIGOT JOINT

DUCTILE IRON BELL & SPIGOT JOINT

CARBON STEEL WELDING

INSTALLATION OF JOINT

Carbon Steel Ductile iron PVC PE GRP0

1

2

3

4

5

Weldability

Electro Fusion Welding

Electro Fusion Welding

ARC Weld-ing

ARC Weld-ing

Pressure

Bead up pressure Heat Soak Pressure

Heat Soak Pressure

Welding Pressure

175 ± 25KPA 5 KPA 0 KPA 175 ± 25KPA

                              

       

     

     

     

     

         

         

               

Bead up Time Heat Soak Time

Max Change Over Time

Time to achieve Cooling Time

pressure

6 t 15* t 3+0.01 *OD 3+0.03 *OD 15*60* t

7.35 min 18.4 min 0.18 min 0.43 min 110.5 min

Welding Time-Minutes

FUSION WELDING-FILED CONSTRAINTS

Pipe misalignment, combined with high fusion pressure, creates an essentially sharp weld bead notch. This may result in premature stress crack failure and reduced impact strength.

Re-crystallization of the melt surface, due to excess cooling before fusion gives a low bond strength brittle region at the interface. This will cause a joint with poor impact strength and brittleness in bending.

If the contamination, are retained at the interface , this will lead to poor bending & impact strength. A

Standard Requirements

PRACTICAL DIFFICULTIES-ONSITEHeavy Re-Rounding Tools

Hand ScrappersRotary Peeler

FFBL PRELIMINARY TRANSIENT MODEL

AFT Impulse ModelD:\AFT Products\AFT Impulse 4.0\K-III.impBase Scenario

P1

P2

J1

J2J3

Pressure Stagnation vs. Time

Pipe 1, Station 0 (Inlet)

Pipe 1, Station 3600 (Outlet)

Pipe 2, Station 0 (Inlet)

Pipe 2, Station 2 (Outlet)

Pres

sure

Stag

natio

n (ps

ia)

Time (seconds)

0

50

100

150

200

0.0 0.2 0.4 0.6 0.8 1.0

As per KW&SB Syphon-9 may pressurize upto 7 bar in the event of upset at downstream

AVAILABILITY IN MARKET

Material Probability in local Market Potential Vendor

Carbon Steel Yes M/s Usman Pvt Limited

Ductile Iron No Aminet International –UAE

PVC No JM Eagle –Europe

HDPE No JM Eagle –Europe

Concrete YesPipe Systems (Pvt) Limited

GRP NoFlowtite Saudi Arabia

CONSIDERATION OF BURIED PIPELINES

Buckling Pressure Deflection External

LoadingSoil

properties

For buried pipe, resistance to external loading is a function of pipe stiffness and passive soil resistance under and adjacent to the pipe.

These two factors play a vital role to create a pipe/backfill system whose stiffness resists the earth and live loads to which the pipe is subjected.

Ductile Iron

Carbon Steel

PVC PE GRP0

102030405060708090

100Buckling Pressure

psi

Ductile Ir

on

Carbon S

teel

PVC PEG

RP0

0.20.40.60.8

11.2

Predicted Deflection

%

Height of Cover = 4 ftSoil type 90 % Compacted

0102030405060708090

Contribution to Deflection

Applicable for Plastics only

00.000010.000020.000030.000040.000050.000060.000070.000080.00009

Coefficient of Thermal Expansion

In/in

/0F

With considerable experience and research, it has now been

established that properly compacted granular materials are ideal for

backfilling pipe.

To reduce the cost of installing pipes, very often the excavated trench

soils are used as pipe zone backfill. However, this may lead to

problems in few cases.

Integrality of buried line incase of using excavated soil became

dependent on pipe properties. Therefore, selection of back fill material

should be given due consideration while selecting pipe materials and

finalizing bedding details.

SOIL TYPES

Sand, silt, and clay are the basic types of soil. Most soils are made up of

a combination of the three. The texture of the soil, how it looks and

feels, depends upon the amount of each one in that particular soil. The

type of soil varies from place to place on our planet and can even vary

from one place to another in our own backyard.

IDEAL BACK FILL MATERIAL

DESCRIPTION OF BACKFILL SOIL

BackfillType

Description Unified Soil ClassificationDesignation, ASTM D2487

A Crushed stone and gravel, < 12% fines

GW, GP, GW – GM, GP - GM

B Gravel with sand, sand, < 12% fines

GW – GC, GP – GC, SW, SPSW – SM, SP – SM, SW – SC, SP - SC

C Silty gravel and sand, 12 – 35% fines, LL < 40%

GM, GC, GM – GC, SM, SC, SM - SC

D Silty, clayey sand, 35 – 50% fines, LL < 40%

GM, GC, GM – GC, SM, SC, SM - SC

E Sandy clayey silt, 50 – 70% fines, LL < 40%

CL, ML, CL - ML

F Low plasticity fine-grained soils,LL < 40%

CL, ML, CL - ML

UNIFIED CLASSIFICATION SYSTEM FOR SOILS

COMPARISON PIPE COST

Carbon S

teel

Concret

e Lin

ed

Ductile

Iron

GRP

PVC PE

Concret

e0

50

100

150

200

250

300

350

400

£/m

WORLD WIDE EXPERIENCE & RECOMMENDATIONS

Characteristics Ductile Iron Steel Pre stressed

Concrete PVC PE GRP

Material category Metal Metal Concrete Plastic Plastic Composite

Internal Corrosion Resistance

Good Poor Good Good Good Good

External Corrosion Resistance

Moderate Poor Good Very good

Very good

Very Good

Life expectancy High High Moderate Low Low Moderate

Primary Use D/T D/T T D D D/T

Effect on Water Quality Low Moderate Moderate Moderate Low Low

Joint Water Tightness Very Good

Very Good

Good Good Poor Good

SA Water Association

Material Authorized Size

Ductile Iron 100 ~750 mm

PVC 100~375 mm

PE 125~355 mm

Carbon Steel 300~ 2000 mm

Regional Council- Peel

PVC For pipe Dia < 300 mm

Concrete / Ductile Iron lined For Pipe Dia ≥ 400 mm

SUMMING UP

Material PVC DI PE Concrete GRP Steel Concrete Lined

Hydraulics 3 4 0 1 5 2 1

Tensile Strength 3 5 2 1 4 5 5

Burst Pressure with Temp correction 1 5 3 2 2 4 4

Stiffness 2 4 3 5 1 5 5

Corrosion Resistance 5 3 5 5 5 2 4

Impact Strength 0 4 3 1 2 5 5

Abrasion Resistance 1 4 3 5 2 3 5

Leakage Rate 5 5 2 3 5 4 5

Weldability 2 1 3 - 2 5 5

Availability 4 3 3 5 3 5 5

22 35 27 23 28 35 39

ENGRO EXPERIENCE WITH PVC LINE

ACHIEVED FLOW

4.2 MGD

OPERATING LIFE

1.5 YEAR

MAJOR BREAK DOWN

8

MINOR BREAK DOWN

0.5 /Month.

Transient flow conditions

PVC Pipe Manufacturing

defects

Inadequate Air vent sizes

Inadequate experience level for Bell and Spigot joint

Installation

Improper bedding & Trenching

Non availability of pressure break tanks

CONCLUSIONS

A number of materials are available for this service. However, none

of the material can be considered as an ultimate and only choice.

Thermo plastics “PVC, PE and GRP” although have good corrosion

resistance properties ,however, poor stiffness, poor Weldability and

requirement of highly skilled man-power for installation are the

main hindrances for selecting these material for 7 MGD Water line

project.

Despite the fact that ductile iron have superior corrosion resistance

properties, impact strength and hydraulic properties , however it

can not be recommended due to its inferior Weldability and huge

cost.

CONCLUSIONS

The selection of material for water pipeline constructions is limited

when all aspects of safety, structural integrity, operating life and

economic considerations are taken into account.

Carbon steel is almost the exclusive choice of the designers for

water transmissions.

Despite excellent Weldability, superior mechanical properties and its

use in water mains for more than a decade, the main issue while

using carbon steel is its inferior corrosion resistance, which can be

addressed by internal cement mortar lining of the pipe as per

AWWA standard

RECOMMENDATIONS

Carbon Steel with cement mortar lining is recommended

material for 7 MGD Water line. Pipe thickness and lining details

shall be finalized during engineering phase.

LAYING AND JOINTING DEFECTS

Seal Fault5.5

Use of Excess Solvent 4.0 %

Insufficient Solvent 10.7 %

Over Insertion 6.7 %

Bending Moment

5.7 %

Back Fill 13.7 %

Impact 5.1 %

OPERATIONAL FACTORS

Solvent Attack 3.2 %

Surge Fatigue 5.7 %Tapping

Failures 2.6 %

Unknown Causes 3.7%

FAILURE OF PVC MAIN IN UK

• PVC water pipe is subject to catastrophic failure.

• Since the damaged area is more extensive, the potential

• for a large contamination event is significantly increased.

• The larger the PVC water main, the greater the impact.

• The manufacturer has confirmed that large diameter pipes

• fail in the same manner as small diameter pipes.

DEFECTS IN GRP PIPELINE

IMPACT DAMAGEIMPACT DAMAGE LACK OF ADHESIVE

INCORRECT RESIN/FIBER RATIOINCORRECT BOND

FIELD CONTAMINATION