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MWANZA SEMINAR
22nd July 2015
PLASCO OVERVIEWPE PIPE JOINTING SYSTEMS
JOINTING TECHNIQUES FOR PE PIPES
There are a number of techniques for jointing of PE pipes
Compression fittings
Stub & flange - mechanical
Butt fusion
Socket fusion requires special fittings
Electro fusion requires special fittings
Compression fittings
Mainly for small diameters
Socket fusion
For small diameters Special fittings and tools required
Mechanical jointing - PE Stub & Flange
For large diameters Especially useful when connecting to other piping systems
Mechanical jointing - PE Stub & Flange
For large diameters Especially useful when
connecting to other piping systems
Mechanical Jointing
Demanding conditions or remote locations
End restraint type fittings
Connecting to other materials and flanges
Butt fusion
Butt fusion technology is the safe,
reliable and favorable method of
jointing for a wide dimension range.
The fusion areas of the pipes and
fittings are heated to fusion
temperature and joined by means of
mechanical pressure, without using
additional materials. A homogeneous
joint results.
Mechanical, hydraulic and CNC-
guided fusion machines for on site
constructions and the workshop are
available.
Butt Fusion Jointing
Preferred option, joint is as strong as the pipe
No fittings required
Continuous fully homogeneous pipe
Butt fusion
For large diameters Straight joints
Custom-made angles for fittings possible
Butt fusion
For large diameters Forming continuous pipelines with flexible and leak free joints
No fluid losses during transportation
Butt fusion video
Electro fusion
In the electro fusion process a heating wire
permanently mouled into the fitting gets
heated by current at a low voltage. The
surrounding material around the wire gets
melted and expands due to the warming. The
melt starts closing the gap between pipe and
fitting, leading to a heat transition to the pipe
which also gets heated and melts in the
welding zone.
The pipe material also expands.
The increasing material expansion between
pipe and fitting, which is hindered by the cold
zones outside the welding zone, leads to a
build up a welding pressure between pipe and
fitting and a homogeneous welding
connection emerges.
Electro fusion
For all diameters Only for jointing PE to PE
To be used when pipes cannot be butt welded
Special fittings and equipment required
Electro fusion video
Electro fusion Branch Saddle
Branching-off without cutting
the pipeline is possible using
Electro fusion Branch Saddles
14
Electro fusion Branch Saddle
System features
Main pipe: d315-2000mm
integratedwindows scraper
Outlet:d160-500mm
Tappingdevice
Cross dimensional, modular installationsystem
freepositioning in axial and radial position
EF Branch Saddle Video
INSTALLATION CONSIDERATIONS
INSTALLATION CONSIDERATIONS
Deliveries and storage on site
Pipe handling
Handling of pipes and fittings on site
Site damage
Thermal effects pipe expansion and contraction
Welding management on site
Deliveries and storage on site straight pipes
Ensure that pipes and fittings are delivered to site with the correct
documentation and that pipes are
marked in accordance with ISO 4427
Generally pipes can be stacked in a regular manner up to a height of 3 m
Pipes should be placed on soft ground or sand. When stored on concrete,
rocky or uneven ground timber battens
should be used
Provided the pipes are produced using a good quality pre-compounded
material the pipes do not need to be
covered or shaded
Deliveries and storage on site coiled pipes
Coils are to be delivered with the correct documentation and
marking
Coiled pipe should be stored flat and on firm level ground which
has protection for the bottom coil.
Where space is limited coils can be stacked up to a height of 2m
Wooden battens placed below the bottom coil and between coils
Where large diameter coils are to be stored vertically, coils must be
secured in racking
Handling of pipes and fittings on site
Pipes should never be thrown or dropped of vehicles or platforms
Always use wide nylon or polypropylene slings rather than
metal slings, hooks or chains
when handling pipes
Place pipes or fittings in contact with lubricating or hydraulic oils,
gasoline, solvents or other
aggressive materials
Do not remove protective covers, bags or end caps until required
Management of site damage
It is not unusual for the pipe surface to be lightly scratched, scuffed or scraped
during installation and this is acceptable
Individual scratches of up to 10% of the pipe wall thickness will not effect the
performance of the pipe (guidelines issued
by the US Plastic Pipes Institute and
several pipe producers)
If there are individual scratches of greater than 10% of the wall thickness or large
areas of very heavy scratching, these
should be cut out and that section of the
pipe discarded
Thermal expansion of PE100 in comparison
to other pipe materials
0 0.5 1 1.5 2
Steel
PVC
HDPE
m
Expansion
Change in the length of a 1 km pipeline with a 10 oC rise
0.1m
0.8m
1.8m
Thermal effects pipe expansion and contraction
The coefficient of thermal expansion for PE100 is 0.18 mm/m/OC
Thermal movement on unrestrained pipes in hot weather will be obvious snaking of the pipeline
Experienced pipe fitters can easily cope with this.
One method is to cut and fix the lengths of pipe at either end when the pipe is relatively cool. If connections are made with a straight pipe
under hot conditions there will be a stress on the joint when the pipe
cools and shrinks
Once buried there is very little thermal movement due to constriction by the backfill, pipe skin friction and a much smaller variation in
temperatures, but still use restrained joints
Welding management - the butt weld process
220C
After positioning of the pipes
end in the welding machine
and planing of the pipe ends
Heating of the pipe ends
until then are semi-molten
Double roll back welded
joint after removal of the
heating element and
cooling under pressure
Pipe
Pipe
Heating element
Welding management on site
- training, certification and good practice
Only welders that trained, tested and certified in accordance with
an international standard (e.g.
Certified HDPE Pipe Welder - GW
330) should operate machines 5 day course
Site staff should be trained and certified as supervisors - 2 or 3
day course
Care and clean site conditions are essential for good welding
Record sheets and/or a welding machine to record every joint
Welding management on site
- training, certification and good practice
Welding management on site
- training, certification and good practicePlasco Limited Field Job Card
Form 07.03.01
Rev: 0
Job Card No
Customer Details
Customer Name IOR/Contract No
Contact Name Tel No
After Hours / Cell No Fax No
Physical Address Date
Safety Considerations
Lockouts Height work Safety Personal Protective Equipment (PPE)
Mechanical Ladders Cranes S/Shoes Earplugs Masks
Electrical Slings Fire Gloves S/Glasses
Reflective Jacket Hard Hat
Customer Requirements
Names of Welding Team
Team Leader Welder 1 Welder 2
Equipment Requirements
Equipment, Machine and Tools Machine No Qty Remarks
Work Times
Date Location Weld
Numbers
Welds
Completed Start Time Finish Time Total Hours
Customers Signature
Additional Comments
Team Leaders Signature Technical Services Manager
Welding management on site examination and testing of welds in the jointing section
Random welds are to the cut out immediately after being
welded and tested in a
laboratory. Some specifications
call for 1% of all welds to be
tested
Initially every joint should be inspected. Once welding
process is up to speed
inspections need only be made
on a regular basis
Visual inspection & bend back testing of the weld beads on a
regular basis gives a good
initial indication of weld quality
Send the welders and supervisor off site!
On site hydrostatic testing of the pipeline
PE is visco-elastic and creeps under stress. The pressure gauge falls back as the pipe expands under pressure.
Therefore with a single phase test it is not possible to tell whether falling pressures are due to leakage or creep of the material
The three phase test eliminates the material response. Therefore any loss of pressure should therefore be from leakage.
Steel pipes are tested primarily for integrity ie. no explosions whilst PE pipes are primarily tested for leak tightness of welded joints.
PE tests must be done in one working day. If any stoppage then depressurise the pipeline and start again.
In hot climates its best to test when temperatures are either stable or falling in order to minimise problems due to thermal pipeline
expansion.
Pipelines are like a chain. They are only as
strong as their weakest link
PE100 pipeline projects must be designed by engineers who are familiar with the
material and whom have been trained in
its proper system design
When comparing pipeline material options designers should consider the entire
construction cost, not just the cost of the
pipes alone. If possible take in to account
the whole life cost of the pipeline utilities need to collect the data!
The pipes must be manufactured from a high quality material (PE100+) in a high
quality facility and in accordance with
national and international standards
Pipelines are like a chain. They are only as
strong as their weakest link
They must be joined by trained and certified welding technicians
using equipped that is tested
and certified in accordance with
international standards
The pipelines must be correctly installed in accordance with the
standards and engineering
specification by an experienced
contractor employing trained
staff
The supervision of the works should be undertaken by a
suitably trained and experienced
site team
Conclusion
33
PE100 pipeline projects must be designed by engineers who are familiar with the material and whom have been trained in its proper system design
When comparing pipeline material options, designers should consider the entire construction cost, not just the cost of the pipes alone. If possible take into account the whole life cost of the pipeline utilities need to collect the data!
The pipes must be manufactured from a high quality material (PE100+) in a high quality facility and in accordance with national and international standards
They must be joined by trained and certified welding technicians using equipment that is tested and certified in accordance with international standards
The pipelines must be correctly installed in accordance with the standards and engineering specification by an experienced contractor employing trained staff
The supervision of the works should be undertaken by a suitably trained and experienced site team
THANK YOU
34
PLASCO LTD.
Your one-stop-shop for
piping solutions
www.plasco.co.tz
Sales Hotlines : +255 717 752 726 / +255 686 350 543 / +255 769 756 495