withGrouted Hot Tap FittingsAn Alternative to Welded Fittings
Presented by: Anna Rattray and Kevin Young
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overview
IntroductionWagga Wagga City Council construction project.
technical considerationsRealign thin wall pipe with uninterruptable gas supply.
technical solutionGrouted tee eliminates need for live pipeline welding.
executionSimple field installation successfully complete.
Conclusion• First onshore application of grouted tees in Australia.
• Future ‘go to’ technology for operationally constrained applications?
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introduction
Wagga WaggaLargest inland city in NSW.
Main Southern Railway line.
Bomen Business ParkRiverina Intermodal Freight and
Logistics (RiFL) Hub location.
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introduction
RiFL Hub road enabling works
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HP gas main impacted:• Operated & maintained by
APA Networks.
• Supply to three commercial
customers.
HP gas main modification
scope:• New alignment of 250m HP
main.
• Tie-in to existing HP main.
• Cut & cap existing HP main.
• Remove redundant section
HP main.
Existing HP main details
Diameter 88.9mm OD
Wall
Thickness
2.7mm
Material CS
(CE = 0.12)
Operating
Pressure
950kPag
MAOP 1050kPag
Year
Commissioned
Est. 1989
(By others)
introduction
APA Networks project
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technical considerations.
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Gas free welding:
• APA Networks preferred practice.
• Pressure reduction unworkable for this HP gas main.
Live pipeline welding:
• Standard practices using low hydrogen electrodes.
• t > 6.4mm → low burn through risk.
• 4.8mm < t < 6.4mm → assess burn through risk.
• t < 4.8mm → high burn through risk.
Welded fittings alternative required:
• Thermal modelling confirmed high burn through risk.
• RiFL Hub project deadline.
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Key selection
criteria:• Safe.
• Reliable.
• Compliant with design
standards.
• Compatible with hot
tap equipment.
Domestic options:Bolt-on fittings.
International option:Grouted tee.
technical considerations
Welded fittings alternative
Bolt-on
Fitting
Grouted
tee
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APA New Materials Process:• Technical and quality
assessment.
Australian & International
standards review.
• Risk assessment.
• Lifecycle cost assessment.
• Fitness for purpose testing.
technical considerations
Grouted tee key benefits:• No live pipeline welding.
• No pressure reduction.
• Design life expectancy > 40
yrs.
• Pressure class 150 to 900.
• Compliant to relevant
standards.
• Compatible to hot tap
equipment.
• Extensive fitness for purpose
testing.
Welded fittings alternative.
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technical solutions.
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Steel shell:• Two half shells bolted together.
• One shell contains the branch.
Saddle seal:• Around neck of branch.
• Provides full pressure
containment.
Epoxy grout: Fills void between outside seal and
bore of shell.
technical solution
DNV GL grouted tee
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Grouted tee design
Compliant to standards:
• IGE/TD/1, IGE/TD/12,
BS80210, ASME B13.3,
ASME B31.8.
• Now AS 2885.
Complex loads:
• Installation.
• Operational.
• Cyclic Pressure.
• Grout.
• Thermal.
technical solution
Grouted tee qualification
Design validation:
• Series of comprehensive finite
element analyses.
• Full-scale test program at
arduous pressures and
environments.
• Analysis for life expectancy in
excess of 40 years.
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Order to delivery process:• Qualification review.
• Component selection.
• Fabrication.
• Assembly.
• Welding.
• NDT.
• Heat treatment.
• Inspection.
• Pressure testing.
• Qualify assurance report.
technical solution
Grouted tee manufacture
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execution.
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execution
Grouted tee installation
HP main realignment required 10 x grouted tees:• 2 x Branch (DN80mm); 4 x Flow stop (DN80mm); 4 x Vent (DN50mm).
Design/manufacture in UK & transported to Australia – 12 weeks.
Installation by DNV GL technicians from Singapore & UK – 3 days.
New HP main commissioned on time, within budget & w/o incident.
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execution
Pipeline surface preparation &
measurement.Grouted tee internal surface
preparation.
Grouted tee installation key steps
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execution
Half shells placed around
pipeline & rotabolts tightened.
Seal integrity (10%) test.
End seal putty applied & grout
pumped into annular space.
Grouted tee installation key steps
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execution
Pressure test (100%) once grout
cured & prior to hot tapping.Hot tapping and mechanical
contractor works followed.
Grouted tee installation key steps
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conclusion.
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conclusion
Hierarchy of controls:
Elimination
Physical controls
Procedural controls
Reduction
Mitigation
Procedural controls:• Qualified low hydrogen
weld procedures.
• Qualified welders.
• Welder supervision /
inspection.
• Thermal modelling.
• Workshop simulation.
Physical controls:Pipe wall thickness.
Elimination:Grouted tee.
Live welding controls
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conclusion
Thicker wallLive welding is low risk of burn
through
Controls adequate &
well practiced
Thinner wallLive welding is
high risk of burn through
Alternative to standard controls?
Best practice to eliminate risk
Live welding controls
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October 2000:First grouted tee installed in the UK.
Now > 830 installed: 55% are high pressure.
Sizes from DN15mm to DN1200mm.
May 2017:First grouted tee installed in Australia.
Grouted tees are:• Safe.
• Reliable.
• Compliant with design standards.
• Compatible with hot tap equipment.
Future: ‘go to’ technology in Australia where
operational constraints necessitate?
conclusion
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conclusion
Any questions
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Acknowledgements & further
information:
For further information contact:
Anna Rattray (APA) Kevin Young (DNV GL)
Senior Gas networks & Pipeline Engineer Group Leader, Safety & Asset Risk Management
+61 9463 8368 +65 98246087
[email protected] [email protected]
Or visit the website at:
www.apa.com.au or www.dnvgl.com
APA Networks Chris Gow Program Coordinator
Aland Cheney Field Supervisor
Michael Gallagher Acting Manager Engineering
Mark Landy Draftsperson
DNV GL Anthony Wood Principal Consultant
Steve Hodge Senior Consultant
Neil Pollock Operations Manager
Project success also due to: