Pipe bursting and Pre-chlorination_effectiveness on large scale projects

PIPE BURSTING AND PRE CHLORINATION

COST EFFECTIVENESS ON LARGE SCALE PROJECTS

THE STATE OF WATER DISTRIBUTION SYSTEMS

PIPE BURSTING AND PRE-CHLORINATION

• Encrusted• Corroded• Water loss up to 40%• Under capacity• Poor water quality

BUSINESS OPPORTUNITY

• EPA estimates 750 billion dollars over next 20 years

• AWWA estimates 1 trillion dollars over next 20 years


NOT ACCEPTABLE!

• The open trench method of replacement is becoming more costly and socially unacceptable.


• Method was developed By British Gas and patented in 1980’s for gas distribution rehabilitation.

• Success led to potable water crossover.• Pipe bursting without protection sleeve accepted along with pre-chlorination

method in early 1990’s in the UK.• Widely accepted in Europe with more than 60,000,000 feet installed in the past

17 years.• Pre-Chlorinated method of pipe bursting is accepted by AWWA in November of

2000.

PIPE BURSTING PRESSURE PIPE


PIPE BURSTING DEFINED

The breaking of an existing pipe, expanding the broken pipe shards into the surrounding soil while simultaneously pulling in the “NEW” carrier line, usually polyethylene pipe (HDPE).


PROJECT CONSIDERATIONSPIPE BURSTING

WHAT IS THE HOST MATERIAL?

• Cast Iron• Clay tile• Concrete• Reinforced Concrete• Asbestos Cement• Non Fracturable Pipe

–Ductile Iron – Challenging–Steel – Challenging–Use Static Machines and Slitters


WHAT MATERIALS CAN BE BURST?


Fracturable PipesCast iron, clay tile, concrete, reinforced concrete, asbestos cement, etc.

Non-fracturable PipesDuctile iron, steel, galvanized (require use of specialized tooling and static bursting machines.

IPBA PROJECT CLASSIFICATION


Project classifications per IPBA (International Pipe Bursting Association) pipe bursting specification.

UPSIZING: A CLOSER LOOK


Note: Illustration assumesflow line remains the same.










UPSIZING – EXPANSION (WHERE IT GOES)


Approximately 90% of compactionoccurs upwards from the existing line.

PRE-CHLORINATION METHODPIPE BURSTING

• A preferred method of water line rehabilitation –Follows path of the existing utility (reduces potential for 3rd party utility damage)–Easement issues and line separation limitations are reduced - the existing utility path is used

–Reduce excavation costs by up to 85%–Able to increase the pipe diameter –Production: Install up to 400’ of pipe in under 2 hours –Pre-chlorination save cost and disruption of installing temporary services–FL- No permitting required for bursting: Classed as a line repair

Pipe Bursting / Pre-chlorination Method


FORT PIERCE, FLORIDA


Pipe Bursting with Pre-chlorination Method using Fusible PVC


PIPE BURSTING SETUP – PUSH OUT ROD


PIPE BURSTING SETUP – ATTACH TOOLING & PIPE


PIPE BURSTING SETUP – PULL BACK


PROJECT CONSIDERATIONS – UK

• Preferred pipe material - Fusible PVC & HDPE.

• Upsizing used only when required–Bursting specifications limited to 1 upsize

• Avoid surface heave and 3rd party utility damage• HDPE Pipe

–Electro-fusion couplers for mains and service connections


Pipe Bursting


Pipe Bursting with Pre-chlorination Method using HDPE


FLOW COMPARISONS: HDPE


FLOW COMPARISONS: HDPE


• Static equipment is most common for water projects• High tonnage static pull back force

–38 ton (2” – 6” pipe)–58 ton (4” – 8” pipe)–100 ton (4” – 16” pipe)–125 ton (6” – 20” pipe)–175 ton (6”- 24” pipe)

• No-contamination of the new Fusible PVC pipe or HDPE.

EQUIPMENT SELECTION


• Received complaints regarding potable water clarity and low pressure concerns• Cast iron water main breaks • New service line installations required • Limited working space, easement issues, and heavy traffic • Expense of open cut not a feasible option• Congested utility infrastructure

WATER MAIN PROBLEMS


TYPICAL JOBSITE


Launch, reception and service pits.

• Flow requirements: HDPE / Fusible PVC Slip-line or Burst?• Site investigation

–Pothole main and confirm main depth, location and material–Review proximity to other utilities

• Sampling Investigations –Downstream Series Sampling:-

• 1 Source • 50 Address (>50μg/litre)

– (>20μg/litre more than source)

–Pre and Post Renovation Sampling:-• 10 Source• 10 Address (>50μg/litre)

– (>20μg/litre more than source)

NETWORK MODELING/PROJECT DESIGN


• Customers are notified of mains replacement project by door hanger outlining the project scope

• Hanger is provided to home owner 48 hours prior to work being performed on their line section

• Approximately 15 to 20 homes will be off water from 8:00 am to 3:00 pm on the day of pipe bursting operations

• Construction crew will be moved onward the following day

CUSTOMER NOTIFICATION


PRE-CHLORINATING PROCEDURES

• Liverpool Depot Coil Pre-chlorinating Operations–Chlorinated Water is filled into the HDPE

pipe coils and left for 24 hours then flushed and a sample taken.


FUSE ON ADAPTORS


–Passed Coils are Marked-up with Gang Name, Location and Sample Reference Number.

–Coils are Stored in goods-out bay prior to collection–Coils are Loaded on to Carousel by fork-lift truck–2 No. Check Sample Points

•To check Dosage of Chloros is maintained at 25 to 30mg/l•To check de-chlorination of water prior to disposal



• Lengths of Main Above and Below Ground Pre-chlorinating Operations–Very similar to coil pre-chlorinating procedure–Source of water from on-site hydrant–All hoses used in operation are pre-chlorinated–Mobile dosage unit is used

• Inputs the required chloros in to the main•De-chlorinates the water prior to discharge to sanitary sewer

–Each length requires a 12 hour dosage period prior to laboratory sample being taken–Results are received next day via fax prior to being put into commission



CONSTRUCTION ACTIVITY: DAY OF OPERATIONS

• Excavate launch, reception and service pits.



• Cut existing cast-iron main, install cap end and secure. Re-establish supply to existing main.



• Position rig into launch and reception pit and pay out rod. (avg. 45 minutes to payout 350’ of rod)



• Guide rod enters reception pit.



• Connect pulling head to fusible PVC or HDPE pipe. Bursting blade and expander to pulling rods.



• Pull back until bursting blade arrives at reception pit. (This takes an average of 45 – 60 minutes for 350’)


• Undertake swabbing exercise• Purge air out of new HDPE main through Installed ferrule at pipe end• Connect cap-end control and pressure test pipe.• Take bacteriological sample• Turn water back on




• Install necessary branches, valves and hydrants.




• Pneumatic piercing tools used for installing new services.


• Install electro-fusion saddles for service connections.



• Backfill excavation and permanently re-instate.


• UK has 13 major water companies serving 66 million people. • Pre-chlorinated Pipe Bursting has nearly obsoleted open trench replacement of

water mains in the UK• USA has approved pre-chlorination in the majority of the US. Pipe Bursting

water mains in the USA will continue to see solid growth, but is currently limited by:–Engineers specifying and water companies embracing HDPE for water rehab jobs–Lack of projects specifying the Pipe Bursting and pre-chlorinated methods

CONCLUSIONS


CASE STUDYBROWNSTOWN WATER IMPROVEMENT PROJECTA joint venture of Bidigare Contractors, Inc., Northville, Michiganand D & D Water & Sewer, Inc., Canton, Michigan.

• Ambitious water-system improvement program that includes replacing nearly eight miles of water mains.

• Most of it with pre-chlorinated HDPE pipe installed by pipe bursting. • It is the first time the Township has installed pre-chlorinated pipe or used pipe

bursting. • Their contract calls for installation of 43,000 feet of new water mains, most of it

8- and 12-inch pre-chlorinated HDPE pipe and installation of fire hydrants and gatewells.

TOWNSHIP OF BROWNSTOWN, MICHIGAN


Existing water main pipes in Brownstown, Michigan.

Setting the down hole machine for the first burst.

Fusion of the new pipe to be installed.

Staging of HDPE pipe sticks for fusion.

The bursting process.

A section of new pipe shown with the tooling required toreplace the existing pipe. The tooling will be attached to the rod string that is pushed out by the down hole unit.

Inside of a connection pit, the bursting process is shown.

Inside of another connection pit, the expander and tooling is shown bursting through old segments of pipe.

CONCLUSION

• Township is so satisfied with how the project progressed; another 30,000 feet of improvements have been added that will extend completion to 2013.

THANK YOU

E: [email protected]: 800.331.6653 | INT: +1.262.567.8833 | F: 262.567.5068W: www.hammerheadtrenchless.com

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Pipe bursting and Pre-chlorination_effectiveness on large scale projects