RESULTS OF A STUDY OF THE RESIDUAL LIFESPAN OF HDPE PIPES USED IN PIPE REPLACING OPERATIONS EMPLOYING PIPE BURSTING AND PIPE SPLITTING NO-DIG TECHNOLOGIES.PLASTIC PIPES XII19th-22th April 2004Grand Dino Hotel, Milan

Torre CarloA.M.G.A. S.p.A. Div Saster Pipe Genoa, Italy

Just few words about No-Dig renewing technologiesMost of renewing no-dig technologies has been designed at the scope to insert a new pipe into an existing old pipeMost of these technologies employing PEHD pipe as liner

Slip Lining is simple, fast and cheap

Roll Down is a close-fittechnology.For this application, we use standard PEHD pipesdeformed on field

Compact Pipe is another close-fittechnology.For this application we use a special PEHD pipe deformed just after the extrusion

Subcoil and Compact SlimLiner are interactive close-fit technologies.For booth applicationswe use a very thin foldedPEHD pipe

and what about pipe replacing?

Pipe Bursting is a No-Dig technology designed to replace a fragile old pipe (grey cast iron, PVC, concrete, asbestos cement, etc) with a new pipe in PEHD.

and pipe splitting?

It is a No-Dig technology, similar to pipe bursting, designed to replace a ductile old pipe (carbon steel, PE, ductile iron, etc) with a new pipe in PEHD

Just a look ontwo significantreplacing projects

Mantova-Italychemical plantExisting pipe: carbon steel ND 10, 12, 14, 16, from 6,6 to 9,4 mm w.t.Depth:> 1,0 < 1,7 mLenght: 1500 metersNew pipe: PE100, SDR 11, ED 250, 315, 355, 400 mmSoil: floodplain gravel in a clayay templateTechnology: Pipe Splitting

Trieste-Italygas distribution networkExisting pipe: grey cast iron ND 100 mmDepth:> 1,3 < 2,5 mLenght: 250 metersNew pipe: PE80, SDR 17, ED 125 mmSoil: large component of fragmented carsic rockTechnology: Pipe Bursting

any consequences on the PE pipe surface after splitting?

and after bursting?

How can we limit the effects of the scratches on the PE surface ?Using the right PE raw materials Knowing and testing the soils beforeChoosing the right pulling speedChecking the PE surface during the pullingUsing +1 step of SDR

and using the right tools/equipment

and how we can test the effects of the scratches ? Making a visual evaluation of the final resultsMeasuring the real depth of the scratchesTesting the PE pipe according to the standards

Why do we need to test?Because we dont have any dedicated EU standards for these No-Dig technologiesBecause pipe replacing technologies are quickly growing in gas, water and oil fields

which tests?Hydrostatic pressure testing with notches (Slow crack propagation) (EN 921)Tensile properties: stress at yield, elongation at break (ISO 6259)

and micrometric surface testit enables us to verify that the real scratches are usually lower than 10% of the wall thickness

after all that based on our experience of more than 90.000 meters of gas & water pipes replaced using pipe bursting & splitting

based on tre results of the mentioned tests, made by a qualified research center (IIP)

and based on the tests made by the end user of some of the projects (Italgas)

We can state that pipe bursting and splitting are technologies applicable in many cases

successful

and safe