HDPE VS GRP

8/13/2019 HDPE VS GRP

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S.No. Parameter HDPE Pipes

1 Suitability toSuitability

to

Transport up to

Field

Pipes & Fittings Material being Tough but

Flexible there is no possibility of damages

during Transport of Pipe to the field from

Manufacturer

2 In-field

Movement

Pipes are Flexible & Tough and hence

no possibility of damages during infield

Movement and Handling

3 Handling Easy to Handle.

Do not break in handling.

4 Feasibility to

Repair

Pipes can be easily Repair on the site itself.

The damaged portion can be easily cut off

and Welded together with the help of asimple butt-fusion machine.

There is no need for a highly skilled

operator for repairing.

5 Installation and

Operation

Jointing is done by Fully Automatic / Semi-

Automatic Butt-Welding / Electro-Fusion

machines, whereby eliminating any scope

for human errors


2/14

3 Jointing Types Very Wide Range of Jointing to suit almost

all other types of pipe materials.

2 Earthquake effect Zero Maintenance piping system.

Unbreakable under Seismic Zones or

Unstable soil areas.

6 Aging Pipes are made of Homogeneous Single

material. Further, because of strong UV

Protection, Aging process is very Slow andPipelines may work even upto 100 years.

9 Inside Surface Inside Surface is very Smooth.

10 Nature of Pipe Visco-Elastic Nature. Can be laid along the

Contour. Very good for Hilly / Mountainous

difficult Terrain also.

Trenching Cost Highly Reduced.

5 Flexibility The Pipe allows a Bending Radius of 25

times the Diameter of Pipe. Reduces the

number of Bends and thus Reduce Loss of

Head due to Friction.


3/14

12 Pumping Energy Lower Pumping Cost due to Lower

Frictional Losses. PE pipe has Better Flow

characteristics

13 Shut-down Wave

Velocity

The shut-down Wave Velocity is half of what

is in GRP piping system.

Safe Leak-Proof Joints.

Negligible Maintenance Cost.

14 Shut-down

Pressure Change

The Shut-down pressure change is also half

of what is in GRP Piping System.

Safe Leak-proof joints.

Negligible maintenance cost.

15 Water Hammer &

Surge

Because of its Visco-Elastic Nature, absorbs

most of the effect of Water Hammer &

Surge and Survives without any damage

16 Thermal

Resistance

PE has good Thermal Resistance and can

sustain a wide range of Temperature

variations between -40 C to +45 C

17 Impact Resistance High Impact Resistance. Can survive

Accidental Impacts.

18 Compatibility Highly Compatible with other Piping

Materials.19 Environmental

Stress Crack

Resistance,

(ESCR )

Very High ESCR,

hence can be used over ground also.


4/14

20 Abrasion

Resistance

Very good Abrasion Resistance.

Gives Very Long Trouble-Free life to

Pipeline, particularly when water is pumped

from Rivers, which may contain Silt / Sand

Particles.

21 Strainability Strainability of PE pipe material is 3 times of

GRP. This enables :

- Easy Installation

- Less Number of Fittings

- Reduced Frictional Loss

- Trouble Free Operation

- Very Low Maintenance Cost

- Sustains Soil-Settlements & Prism Loads

very well

- Sustains through Earthquakes.

Kobe, Japan is very good example.

The report is officially available.

22 Environmental

Effect

HDPE is a Thermoplastic Plastic Material

which can be recycled and hence is

Environmentally friendlier.

23 Inside

Outside

Smoothness

Polyethylene pipes manufactured by

extrusion have a Smooth Internal & External

Surface.

24 Water Absorption HDPE pipe have a negligible value of water

absorption of 0.03 % and no impact on

strength of pipe.


5/14

GRP Pipes

Pipes & Fittings are Light, Delicate and Rigid.

Damages due to Impacts during

Transportation

are Very High.

Pipes being Light, Delicate and Rigid the pipes

get damaged / Broken quite Frequently

during

the Infield Movement.

Careful Handling is necessary.

The pipes get broken easily.

For Repairing the damaged pipes skilled

personnel are needed.

Jointing involves Skill & Experience of the

operator. Human error is evident depending

upon the person to person.


6/14

I. Restrained Joints: Pipe joints capable of

withstanding internal pressure and

axial load due to internal pressure.

1. Flanged Joint

(i) Fixed flange

(ii) Stub end with loose flange

2. Butt & Wrap Joint

3. Adhesive Bonded Joint(Bell & Spigot withAdhesive)

4. Rubber Seal Lock Joint (Bell & Spigot with

Rubber Sealing Rings and a

Locking Key)

II. Unrestrained Joints: Pipe joints capable of

withstanding only hoop loading

due to internal pressure. In this type, the axial

forces in the system have to be

taken by external provisions on the pipeline.

1. Coupler with Rubber Sealing Rings

2. Bell & Spigot with Rubber Sealing Rings

Pipeline breaks under Seismic Zones or


Because of Compounded Material, Fast Aging

of pipe material takes place, Restricting Life of

pipe-line to below 30 years.

Inside Surface is not as Smooth as that of

HDPE.

Rigid. Need Flat-Bed trenches.

Not Suitable for difficult Terrain.

Trenching Cost Increases Highly.

Pipes are Rigid and use of Bends is must.

Increased Loss of Head due to Friction.


7/14

Higher Pumping Cost due to Higher

Frictional Losses. This is easily computed

as the C value of GRP pipe is much less

(16% less) than PE pipe. This leads to more

Frictional Loss in GRP Pipe and more energy

exerted for Pumping Per Kilo-Litre of Water.

This is a recurring drain in the users pocket.

The Shut-Down Wave Velocity is Double that

of

what is in HDPE Piping System.

More Joint Failures and Increased

MaintenanceCost.

The Shut-Down pressure change is double

that

of what is in HDPE Piping System.

More Joint Failures and Increased

Maintenance

Cost.

Rigid. Breaks under Water Hammer & Surge

or

needs Specials, Valves / Fittings to absorb theeffect.

GRP becomes Brittle at Low Temperatures and

thus prone to breakage.

Comparatively Low Resistance to Impacts.

The pipes get damaged easily.

Not easily Compatible with other Piping

Materials.Low ESCR.

Not suitable for On ground and Over ground

applications.


8/14

Prone to Abrasion. Pipes gets Damaged Faster

due to Poor Abrasion and need Replacement,

particularly when water is pumped from

Rivers,

which may contain Silt / Sand Particles.

Strainability of GRP pipe material is 1/3rd of

PE

Pipes.

- Installation troublesome

- More number of fittings required

- Higher frictional loss

- Breakage trouble

- Higher maintenance cost

- Succumb to soil-settlements &

Prism Loads.

- Pipe-lines break due to earthquakes.

GRP is a Thermoset Material which cannot be

recycled hence Environmentally Hazardous.

GRP piping based on Thermoset Systems will

have either a True Inside Surface or a True

Outside Surface but not both surfaces.Pipings made by Filament Winding have a

good finish on the Inside while those made

by Centrifugal Casting have a Smooth Outside

Surface.

Water absorption of GRP pipes ranges from

0.2 % to 0.8 %. Permeation of this water into

the polymer matrix could weaken the glass to

resin bond.


9/14

4


10/14


11/14

S.No. Parameter HDPE Pipes

7 ease to work Jointing is done by Fully Automatic / Semi-

Automatic Butt-Welding / Electro-Fusion

machines, whereby eliminating any scope

for human errors

3 Jointing Types Very Wide Range of Jointing to suit almost

all other types of pipe materials.

2 Earthquake effect Zero Maintenance piping system.

Unbreakable under Seismic Zones or


6 Aging Pipes are made of Homogeneous Single

material. Further, because of strong UV

Protection, Aging process is very Slow and

Pipelines may work even upto 100 years.

9 Inside Surface Inside Surface is very Smooth.

5 Flexibility The Pipe allows a Bending Radius of 25

times the Diameter of Pipe. Reduces the

number of Bends and thus Reduce Loss of

Head due to Friction.


12/14

21 Strainability Strainability of PE pipe material is 3 times of

GRP. This enables :

- Easy Installation

- Less Number of Fittings

- Reduced Frictional Loss

- Trouble Free Operation

- Very Low Maintenance Cost

- Sustains Soil-Settlements & Prism Loadsvery well

- Sustains through Earthquakes.

Kobe, Japan is very good example.

The report is officially available.


13/14

GRP Pipes

Jointing involves Skill & Experience of the

operator. Human error is evident depending

upon the person to person.

1. Flanged Joint

(i) Fixed flange

(ii) Stub end with loose flange

2. Butt & Wrap Joint

3. Adhesive Bonded Joint(Bell & Spigot with

Adhesive)

4. Rubber Seal Lock Joint (Bell & Spigot with

Rubber Sealing Rings and a

Locking Key)

5. Coupler with Rubber Sealing Rings

6. Bell & Spigot with Rubber Sealing Rings

Pipeline breaks under Seismic Zones or


Because of Compounded Material, Fast Aging

of pipe material takes place, Restricting Life of

pipe-line to below 30 years.

Inside Surface is not as Smooth as that of

HDPE.

Pipes are Rigid and use of Bends is must.

Increased Loss of Head due to Friction.


14/14

Strainability of GRP pipe material is 1/3rd of

PE

Pipes.

- Installation troublesome

- More number of fittings required

- Higher frictional loss

- Breakage trouble

- Higher maintenance cost- Succumb to soil-settlements &

Prism Loads.

- Pipe-lines break due to earthquakes.

HDPE VS GRP

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