Definition and History of Cured-in-place Pipe

Cured-in-place pipe (CIPP) is a trenchless excavation method for renovating existing underground pipelines without digging them up. It involves inserting an inflatable and resin-impregnated tube into the existing pipe and using steam, water or UV light to cure the resin and form a new pipe inside the old one. Once cured, the new pipe takes the shape of the host pipe.

CIPP lining originated in Britain in the 1960s using cotton-felt tubes and epoxy resins. The first commercial Cured-In-Place Pipe  project took place in Germany in 1971. Since then, it has become widely adopted around the world as a cost-effective method for rehabilitating sewer, water and other buried pipes deteriorated by corrosion, cracks or structural deterioration.

Types of CIPP Material and Processes

There are several types of material and curing processes used for CIPP:

– Felt tube with thermosetting resin – This is the most common type. A flexible fabric tube impregnated with thermosetting resin is inserted into the host pipe. Hot water or steam is then circulated inside to cure the resin.

– Non-woven tube with thermosetting resin – Similar to felt tube but using a non-woven felt material, offering better resistance to chemical and hydraulic conditions. Cured using hot water or steam.

– Fiberglass tube with thermosetting resin – Glass fibers are woven into a cylindrical tube to add strength. Cured using hot water or steam.

– Inverted cure lining – The tube is inverted from inside the pipes typically using water pressure. UV light is then used to cure the resin. It avoids excessive heat exposure to the host pipe.

Advantages and Applications of CIPP Lining

CIPP provides numerous advantages over open-cut pipe replacement methods:

– Minimal excavation required – Significantly reduces surface disruption and costs compared to digging long trenches for pipe replacement.

– Fast installation – Pipes can be renovated at a rate of up to 250 feet per day. Quicker project completion and less disruptions.

– Structural enhancement – The resin forms a new structurally sound pipe inside that is impermeable and more durable than the original.

– Increased hydraulic capacity – CIPP reduces pipe internal surface roughness, enlarging flow area and increasing hydraulic capacity by up to 40%.

– Extends service life – Expected minimum 50-year service life from CIPP versus 20-30 years from conventional pipe materials.

– Lower lifecycle costs – Avoiding excavation results in savings of 60-70% over full replacement costs.

CIPP is widely used for renovating sewer pipes, storm drains, water mains and other buried municipal, industrial and commercial pipes up to 12 feet in diameter. It is an ideal structural rehabilitation method for existing underground infrastructure with accumulated defects and reduced service life.

Inspection and Testing Prior to CIPP Lining

Prior to CIPP installation, the host pipe condition must be thoroughly assessed through:

– CCTV camera inspection – TV camera is pulled through the pipe to visually record and assess any breaks, cracks, joint failures, excessive infiltration, root intrusions etc.

– Mandrel test – A rigid steel rod with diameter smaller than specified is pulled through to check for proper internal deformations.

– Caliper scanning – Computerized scanning determines pipe internal geometry, ovality and structural defects for proper sizing of CIPP tube.

– Debris and obstruction removal – Any debris or major obstructions inside the pipe are cleaned out to allow unhindered installation of CIPP tube.

This pre-lining inspection and testing ensures suitability of the host pipe for CIPP rehabilitation and design of the proper CIPP tube for a tight-fitted install. It also establishes a baseline for assessing post-lining improvements.

CIPP Installation Process

The standard steps involved in the CIPP installation process are:

– Bypass pumping – Sewage flow in active pipes is bypassed around the installation segment using pumps and temporary piping.

– Pipe cleaning and inspection – Final cleaning and television inspection verifies suitability for lining.

– Tube impregnation – The resin-absorbent fabric tube is soaked in a controlled amount of thermosetting resin under vacuum.

– Tube insertion – The saturated tube is inserted into the host pipe using water pressure or mechanical means and remotely inflated.

– Resin curing – Hot water or steam (for felt tube) or UV light (for inversion processes) is used to cure the resin and form a rigid new pipe within.

– Cool-down and reinstatement – The installed liner cools and hardens in-place. Service connections are reinstated and bypass pumping is removed.

– Post-lining inspection – Final CCTV verifies quality of installation, defects or failures are addressed. Hydraulic testing is sometimes conducted.

when done properly with quality control, the CIPP process can provide durable, long-lasting structural rehabilitation to underground piping systems. Periodic inspection and maintenance further extends the service life gained from CIPP lining.

*Note:
1.Source: Coherent Market Insights, Public sources, Desk research
2.We have leveraged AI tools to mine information and compile it