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

anna.rattray@apa.com.au kevin.young@dnvgl.com

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: