TECHNOLOGIES AND METHODS FOR REHABILITATION OF FORCE MAINS
Purpose Statement: To provide a brief overview of pipeline rehabilitation technologies for the purposes of education and comparison. Further guidance can be sourced by consulting an expert in trenchless technology and representatives of the technologies.
TECHNOLOGY: SEGMENTAL OR DISCRETE SLIPLINING
Overview
Segmental sliplining involves lining with pipe segments shorter than the section being rehabilitated, where the pipe cross-section remains unchanged during and after installation. This method results in an annular gap between the slipline pipe and the existing pipe, which is typically grouted.
Materials and Rehabilitation Method
Material 1
Polyvinyl Chloride
(PVC)
Material 2
Fiberglass Reinforced Polymer Pipe
(FRP)
Material 3
Rehabilitation Method
Pipe segments are dropped into an existing pipe through access pits. Then the segments are pushed together progressively into the existing pipeline. Both circular and noncircular sections can be sliplined using spacers to ensure the slipline pipe remains centered within the existing pipe. Annulus grouting may be required following the insertion of the slipline pipe to ensure that the existing pipe structure provides adequate restraint and enhances ring stiffness.
Technical Envelope
Diam Range
12 to 84 in.
Structural Classification
Class III and Class IV
(Semi-Structural and Fully Structural)
(Semi-Structural and Fully Structural)
Hazen Williams Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
PVC: PVC and DI Fittings
FRP: Flange adapters, backup rings, MJ adapters
FRP: Flange adapters, backup rings, MJ adapters
Comments
Medium footprint
Installation length can reach more than 5,000 LF on a single installation
Pressure ratings up to ~300 psi
May accommodate 11 1/4-degree deflection dependent upon material, pipe size and annular space
Does not require consistent I.D. of host pipe
This method of sliplining incorporates grouting the annular space after install
To accommodate for grouting a minimum of 38 mm (1.5 in.) annular space is typical, plus the wall of the new pipe, which is designed for the operating conditions
Installation length can reach more than 5,000 LF on a single installation
Pressure ratings up to ~300 psi
May accommodate 11 1/4-degree deflection dependent upon material, pipe size and annular space
Does not require consistent I.D. of host pipe
This method of sliplining incorporates grouting the annular space after install
To accommodate for grouting a minimum of 38 mm (1.5 in.) annular space is typical, plus the wall of the new pipe, which is designed for the operating conditions
TECHNOLOGY: CONTINUOUS SLIPLINING – LOOSE FIT
Overview
Continuous sliplining uses a long continuous pipe that is pulled through the existing pipe starting at an insertion pit and continuing to a receiving pit. Loose fit pipe has a smaller diameter than the host pipe.
Materials and Rehabilitation Method
Material 1
Polyvinyl Chloride (PVC)
Material 2
Fusible PVC
(FPVC)
Material 3
HDPE
Rehabilitation Method
Loose fit sliplining involves pulling a continuous HDPE, PVC, or FPVC pipe, fused or jointed before insertion, into an existing pipeline. The annular space between the slipline pipe and the host pipe is typically grouted.
Technical Envelope
Diam Range
4 to 60 in.
Structural Classification
Class III and Class IV
(Semi-Structural and Fully Structural)
(Semi-Structural and Fully Structural)
Hazen Williams Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
PVC: PVC and DI Fittings
HDPE: Flange adapters,
backup rings, MJ
adapters
Comments
PVC, FPVC, HDPE: Large footprint as pipe is fused prior to insertion
Installation length per setup can reach more than 7,000 LF on a single pull
Operating pressures up to ~300 psi
May accommodate 11 1/4-degree deflection dependent upon material, pipe size and annular space
Does not require consistent I.D. of host pipe
This method of sliplining incorporates grouting the annular space after install
To accommodate for grouting a minimum of 38 mm (1.5 in.) annular space is typical, plus the wall of the new pipe, which is designed for the operating conditions
Installation length per setup can reach more than 7,000 LF on a single pull
Operating pressures up to ~300 psi
May accommodate 11 1/4-degree deflection dependent upon material, pipe size and annular space
Does not require consistent I.D. of host pipe
This method of sliplining incorporates grouting the annular space after install
To accommodate for grouting a minimum of 38 mm (1.5 in.) annular space is typical, plus the wall of the new pipe, which is designed for the operating conditions
TECHNOLOGY: CONTINUOUS SLIPLINING – MODIFIED LOOSE FIT
Overview
Flexible Fabric Reinforced Pipe (FFRP) is another continuous, loose fit slipliner material consisting of a reinforced hose that is modified prior to insertion into the existing pipe and has a different technical envelope than other loose fit slipliner materials.
Materials and Rehabilitation Method
Material 1
Flexible Fabric Reinforced Pipe (FFRP)
Material 2
Material 3
Rehabilitation Method
The FFRP is factory-manufactured round pipe that is modified into a “C” or “U” shape and coiled onto reels. The installation consists of a continuous supply of modified pipe being winched through the existing pipe and reverted to its manufactured “round” shape by air pressure.
Technical Envelope
Diam Range
6 to 20 in.
Structural Classification
Class III
(Semi-Structural)
(Semi-Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
Flange end fittings and
adapters
Comments
Small footprint
Installation length per setup can reach over 8,000 LF
Pressure ratings can exceed 1,000 psi
Can accommodate multiple bends including 90 degree bends
Does not require consistent I.D. of host pipe
Semi-structural. Does not support external loads.
Installation length per setup can reach over 8,000 LF
Pressure ratings can exceed 1,000 psi
Can accommodate multiple bends including 90 degree bends
Does not require consistent I.D. of host pipe
Semi-structural. Does not support external loads.
TECHNOLOGY: CONTINUOUS SLIPLINING – CLOSE FIT
Overview
Continuous sliplining uses a long continuous pipe that is pulled through the existing host pipe starting at an insertion pit and continuing to a receiving pit. Close-fit pipe is folded or reduced to facilitate installation, then reverted to provide a compression fit to the existing pipe. Close fit sliplining is also referred to as compressed fit or swagelining when using a continuous HDPE pipe.
Materials and Rehabilitation Method
Material 1
HDPE
Material 2
Flexible Reinforced Plastic
Hose (FRPH)
Material 3
Rehabilitation Method
The installation consists of a continuous supply of pipe that is slightly larger than the I.D. of the existing pipe that is temporarily compressed or reduced in diameter during insertion into the host pipe. After installation the new pipe rebounds back outward, fitting tightly against the host pipe wall.
Technical Envelope
Diam Range
HDPE: 16 to 63 in.
FRPH: 4 to 54 in.
FRPH: 4 to 54 in.
Structural Classification
Class III and Class IV
(Semi-Structural and Fully Structural)
(Semi-Structural and Fully Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
Flange adapters, backup
rings, MJ adapters
Comments
Small footprint when installing FRPH which is wound on a reel
Large footprint as HDPE pipe must be strung out in its entirety
Installation length per setup can reach up to 5,000 LF on a single pull dependent upon installation method
Class III solution accommodating internal pressure up to 58 psi when using FRPH
Class IV pressure up to 126 psi when using HDPE
Class IV solution accommodating both internal pressure and external loading when using HDPE
May accommodate 11 1/4-degree deflection when using HDPE; 45-degree when using FRPH
Reduces internal diameter a minimum of 13 mm (0.5 in.) or greater when using HDPE; 20 mm (0.8 in.) or greater when using FRPH
Large footprint as HDPE pipe must be strung out in its entirety
Installation length per setup can reach up to 5,000 LF on a single pull dependent upon installation method
Class III solution accommodating internal pressure up to 58 psi when using FRPH
Class IV pressure up to 126 psi when using HDPE
Class IV solution accommodating both internal pressure and external loading when using HDPE
May accommodate 11 1/4-degree deflection when using HDPE; 45-degree when using FRPH
Reduces internal diameter a minimum of 13 mm (0.5 in.) or greater when using HDPE; 20 mm (0.8 in.) or greater when using FRPH
TECHNOLOGY: CURED-IN-PLACE PIPE (CIPP)
Overview
Cured-In-Place Pipe (CIPP) consists of a resin-saturated tube (liner) that is inserted into the existing pipe and cured to produce a new pipe within the host pipe.
AWWA/ANSI Standard C623 Cured-In-Place Pipe (CIPP) Rehabilitation of Pressurized Potable Water Pipelines, 4 in. (100 mm) and Larger can be referenced for the rehabilitation of potable water mains using CIPP.
AWWA/ANSI Standard C623 Cured-In-Place Pipe (CIPP) Rehabilitation of Pressurized Potable Water Pipelines, 4 in. (100 mm) and Larger can be referenced for the rehabilitation of potable water mains using CIPP.
Materials and Rehabilitation Method
Material 1
Tube – fiber reinforced felt, or fiber reinforcement
Material 2
Thermoset Resin – epoxy or vinyl ester
Material 3
Rehabilitation Method
The tube is saturated with a thermoset resin and installed into the existing pipe either by directly inverting the liner into position using water or air pressure (ASTM F1216) or by pulling the liner into the host pipe using a winch (ASTM F1743). Once in place and properly inflated, the liner is cured by circulating hot water or controlled steam, or by exposure to UV light (i.e., photoinitiated reaction).
Technical Envelope
Diam Range
6 to 72 in.
Structural Classification
Class III and Class IV
(Semi-Structural and Fully Structural)
(Semi-Structural and Fully Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
Hymax couplings and mechanical end seals used at CIPP termination.
Comments
Medium footprint
Installation length per setup subject to diameter and thickness (up to 1,200 LF)
Pressure ratings up to 250 psi – larger diameter, lower MAOP
Can accommodate 45-degree and sweeping 90-degree bends
Class IV solution accommodating both internal pressure and external loading
Resin impregnation (wet-out) of the tube may be in a factory setting, or on-site (over-the-hole)
Lining thickness is 4 to 15 mm (0.2 to 0.6 in.)
Installation length per setup subject to diameter and thickness (up to 1,200 LF)
Pressure ratings up to 250 psi – larger diameter, lower MAOP
Can accommodate 45-degree and sweeping 90-degree bends
Class IV solution accommodating both internal pressure and external loading
Resin impregnation (wet-out) of the tube may be in a factory setting, or on-site (over-the-hole)
Lining thickness is 4 to 15 mm (0.2 to 0.6 in.)
TECHNOLOGY: SPRAY-IN-PLACE POLYMER (SIPP)
Overview
Spray-in-place polymer (SIPP) involves applying a polymeric resin to the cleaned and prepared interior walls of the force main.
AWWA/ANSI Standard C620 Spray-In-Place Polymeric Lining for Potable Water Pipelines, 4 in. (100 mm) and Larger can be referenced for rehabilitation of potable water mains using polymeric resins.
AWWA/ANSI Standard C620 Spray-In-Place Polymeric Lining for Potable Water Pipelines, 4 in. (100 mm) and Larger can be referenced for rehabilitation of potable water mains using polymeric resins.
Materials and Rehabilitation Method
Material 1
Polyurethane
Material 2
Epoxy
Material 3
Polyurea
Rehabilitation Method
After thorough cleaning and surface preparation of the existing pipe, the selected polymeric material is metered and pumped using specialized equipment for application by either worker-entry or robotic devices, which spray or cast the polymer onto the interior surfaces of the host pipe. The material is applied in one or more coats to form a continuous liner.
Technical Envelope
Diam Range
4 in. and larger
Structural Classification
Class I to Class III
(Non-Structural to Semi-Structural)
(Non-Structural to Semi-Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
End seals are typically not required for SIPP applications because of their adhesion to the existing pipe surfaces.
Comments
Small footprint
Application length per setup subject to diameter and thickness (typically up to 1,000 LF)
Not rated for internal pressure (dependent on host pipe)
May require multiple layers to achieve desired thickness
Cleaning and surface preparation of host pipe wall is critical
Lining thickness is 40 to 500 mils (1 to 13 mm, or up to 0.5 in.)
Application length per setup subject to diameter and thickness (typically up to 1,000 LF)
Not rated for internal pressure (dependent on host pipe)
May require multiple layers to achieve desired thickness
Cleaning and surface preparation of host pipe wall is critical
Lining thickness is 40 to 500 mils (1 to 13 mm, or up to 0.5 in.)
TECHNOLOGY: SPRAY-APPLIED PIPE LINING (SAPL)
Overview
Spray-applied pipe lining (SAPL) using geopolymer materials may be appropriate to provide corrosion protection in large-diameter concrete sewer force mains where pressure is moderate and surge is controlled.
Materials and Rehabilitation Method
Material 1
Geopolymer
Material 2
Material 3
Rehabilitation Method
After cleaning and surface preparation of the host pipe, the selected material is pumped into the existing pipeline and applied using either centrifugal casting or shotcrete hand spray, with or without hand troweling for finishing.
Technical Envelope
Diam Range
36 to 120 in.
Structural Classification
Class II and Class III
(Non-Structural to Semi-Structural)
(Non-Structural to Semi-Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
125 to 135
Connections (ARVs), Terminations and End Seals
New connections performed in traditional manner (saddles, spools, etc.) No end seals required at coating termination.
Comments
Medium footprint
Installation Application length per setup subject to diameter and thickness (typically up to 700 LF)
Not rated for internal pressure (dependent on host pipe)
Relies on adhesion to host pipe
Cleaning and surface preparation of host pipe wall is critical
Lining thickness is 25 to 100 mm (1 to 4 in.)
Installation Application length per setup subject to diameter and thickness (typically up to 700 LF)
Not rated for internal pressure (dependent on host pipe)
Relies on adhesion to host pipe
Cleaning and surface preparation of host pipe wall is critical
Lining thickness is 25 to 100 mm (1 to 4 in.)
TECHNOLOGY: WET LAY-UP OF FIBER REINFORCED POLYMER
Overview
The wet lay-up of fiber reinforced polymer consists of application of a composite that includes a polymer and a reinforcement material.
AWWA/ANSI Standard C305 CFRP Renewal and Strengthening of Prestressed Concrete Cylinder Pipe (PCCP) can be referenced for rehabilitation of potable water PCCP pipe using carbon fiber reinforced polymer (CFRP).
AWWA/ANSI Standard C305 CFRP Renewal and Strengthening of Prestressed Concrete Cylinder Pipe (PCCP) can be referenced for rehabilitation of potable water PCCP pipe using carbon fiber reinforced polymer (CFRP).
Materials and Rehabilitation Method
Material 1
Epoxy
Material 2
Fiberglass Fabric
Material 3
Carbon Fiber Fabric
Rehabilitation Method
The installation is accomplished through the manual wet lay-up method, also known as the hand lay-up technique. The reinforcement fabric is impregnated with resin at the site and then applied to the interior surface of the pipe in a specific sequence, both circumferentially and longitudinally. This technology requires worker entry for application.
Technical Envelope
Diam Range
36 to 120 in.
Structural Classification
Class III and Class IV
(Semi-Structural and Fully Structural)
(Semi-Structural and Fully Structural)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
New connections performed in traditional manner (saddles, spools, etc.)
No end seals required at coating termination
No end seals required at coating termination
Comments
Small footprint
Installation is hand applied and subject to confined space entry
Pressure ratings can exceed 450 psi
Can accommodate bends
Class IV solution accommodating both internal pressure and external loading
Does not require consistent host pipe inside diameter
Reduces internal diameter a maximum of 13mm (0.5 in.)
Can be used externally
Installation is hand applied and subject to confined space entry
Pressure ratings can exceed 450 psi
Can accommodate bends
Class IV solution accommodating both internal pressure and external loading
Does not require consistent host pipe inside diameter
Reduces internal diameter a maximum of 13mm (0.5 in.)
Can be used externally
TECHNOLOGY: PIPE BURSTING
Overview
Pipe bursting is a technology that uses static or pneumatic methods to burst, fracture, or split the existing pipeline, displacing it into surrounding soils while pulling a new pipe through the same path as the existing pipeline. A unique characteristic of pipe bursting is the ability to upsize the diameter and thus capacity of the existing pipeline.
AWWA/ANSI Standard C602 Pipe Bursting of Potable Water Mains, 4 in. (100 mm) to 36 in. (900 mm) can be referenced for potable water applications.
AWWA/ANSI Standard C602 Pipe Bursting of Potable Water Mains, 4 in. (100 mm) to 36 in. (900 mm) can be referenced for potable water applications.
Materials and Rehabilitation Method
Material 1
HDPE
Material 2
Polyvinyl Chloride
(PVC)
Material 3
Fusible PVC
(FPVC)
Rehabilitation Method
A bursting head is pulled through the existing pipe, fracturing it outward into the surrounding soil while simultaneously installing a new pipe behind it. The process typically requires launch and receiving pits, temporary bypass pumping, and a pulling system to guide the bursting head and replacement pipe along the existing alignment. This technology makes sense for pipelines constructed of consistent materials, relatively straight alignment, and consistent depths of bury and bedding, with parallel separation from other utilities.
Technical Envelope
Diam Range
4 to 48 in.
Structural Classification
Class IV
(Structural Replacement, Upsize I.D. / Capacity)
(Structural Replacement, Upsize I.D. / Capacity)
Hazen Williams
Coefficient (typical values)
Coefficient (typical values)
140 to 150
Connections (ARVs), Terminations and End Seals
PVC: PVC and DI Fittings
HDPE: Flange adapters, backup rings, MJ adapters
HDPE: Flange adapters, backup rings, MJ adapters
Comments
Large footprint
Installation length per setup can reach up to 2,000 LF
Pressure rating dependent on replacement pipe
May accommodate up to a 22 1/2-degree deflection
Can enable pipe diameter upsizing
Does not require consistent I.D. of host pipe.
Class IV solution accommodating both internal pressure and external loading
Installation length per setup can reach up to 2,000 LF
Pressure rating dependent on replacement pipe
May accommodate up to a 22 1/2-degree deflection
Can enable pipe diameter upsizing
Does not require consistent I.D. of host pipe.
Class IV solution accommodating both internal pressure and external loading