Trenchless Pipeline Rehabilitation Technology - Lining Method‌

I. Introduction

Drainage pipeline systems form the vital infrastructure of modern cities, facilitating the safe conveyance of wastewater and stormwater while preventing flooding and environmental pollution . However, as urbanization continues to accelerate and existing infrastructure ages, the need for efficient, cost-effective pipeline rehabilitation methods has become increasingly critical (21). Traditional open-cut repair methods present significant challenges including traffic disruption, environmental impact, high costs, and extended project timelines (30).

Cured-in-Place Pipe (CIPP) lining, also known as "no-dig" or trenchless technology, has emerged as a revolutionary solution for pipeline rehabilitation, offering substantial advantages over conventional methods (31). This comprehensive guide provides engineering professionals with detailed insights into CIPP lining technology, including its operational ，international standards compliance, case studies, and comparative analysis with alternative pipeline repair techniques .

The CIPP method involves inserting a resin-impregnated flexible tube into the existing pipeline, inflating it to conform to the host pipe's interior, and curing it in place to form a durable new pipe within the old one (21). This technique was first developed by Eric Wood in 1971 and has since evolved into a sophisticated rehabilitation method used globally for rehabilitating pipelines with minimal disruption to urban environments (21).

II. Technical Principles and Operational 

2.1 Basic Technology Principles

CIPP lining operates on the principle of creating a structural composite pipe within the existing host pipe through a combination of resin-impregnated materials and controlled curing processes (1). The fundamental concept involves:

1. Resin Impregnation: A felt or fabric tube is saturated with a thermosetting resin system, typically polyester, vinyl ester, or epoxy (1).
2. Installation: The impregnated tube is inverted or pulled into the existing pipeline where it conforms to the internal surface (3).
3. Inflation: The tube is pressurized (either with air, water, or steam) to ensure full contact with the host pipe .
4. Curing: The resin is cured using heat (hot water, steam) or ultraviolet (UV) light, transforming the flexible tube into a rigid structural liner (1).
5. Final Inspection: After curing, the liner is inspected to ensure proper installation and structural integrity (12).

The resulting CIPP liner forms a tight-fitting, seamless pipe that restores structural integrity while providing excellent resistance to corrosion and abrasion (16). The technology can be used for both gravity-fed sewer systems and pressure pipelines, with design considerations varying based on application (14).

2.2 Detailed Operational 

The CIPP installation process can be divided into several distinct phases, each requiring careful planning and execution to ensure successful outcomes (19).

2.2.1 Pre-installation Preparation and Inspection

Before any rehabilitation work begins, a thorough inspection of the existing pipeline is essential (40):

1. Pipeline Inspection: Advanced inspection tools such as closed-circuit television (CCTV) cameras, laser profiling, and sonar systems are used to assess the condition of the pipeline, identify defects, and determine the suitability for CIPP lining (12).
2. Cleaning: The pipeline is thoroughly cleaned to remove debris, scale, roots, and other obstructions that could interfere with liner installation or adhesion (40).
3. Pre-design Assessment: Based on inspection data, engineers design the appropriate CIPP system, selecting the right resin type, reinforcement materials, and curing method for the specific application .

2.2.2 Liner Fabrication and Insertion

The core of the CIPP process involves creating and placing the liner within the host pipe (3):

1. Resin Selection: The choice of resin depends on factors such as chemical resistance requirements, curing method, and environmental conditions. Common options include polyester, vinyl ester, and epoxy resins (1). Recent advancements include styrene-free vinyl ester resins that significantly reduce volatile organic compound (VOC) emissions (5).
2. Fabrication: The selected resin is impregnated into a carrier material, typically a felt or woven fabric. For structural applications, glass fiber reinforcement may be incorporated to enhance mechanical properties (16).
3. Insertion Methods:
   • Inversion: The resin-impregnated tube is inverted into the host pipe using water or air pressure, ensuring complete coverage (21).
   • Pull-in-Place: The liner is pulled through the existing pipeline using winches or other mechanical means (3).
   • Sectional Installation: For larger diameter pipes or complex geometries, the liner may be installed in sections and joined in place .

2.2.3 Inflation and Curing Processes

Once inserted, the liner must be properly inflated and cured to form a structurally sound pipe (1):

1. Inflation: The liner is pressurized to ensure full contact with the host pipe. This can be achieved through:
   • Water Pressure: Clean water is used to inflate the liner, providing uniform pressure distribution (14).
   • Air Pressure: Compressed air offers precise pressure control and easier removal after curing .
   • Steam Inflation: Simultaneously provides both pressure and heat for curing, reducing overall project time (14).
2. Curing Methods:
   • Hot Water Curing: The liner is cured using circulated hot water (typically 80-95°C), providing consistent heat distribution (16).
   • Steam Curing: High-temperature steam (up to 130°C) accelerates the curing process, suitable for large-diameter pipes or time-sensitive projects (14).
   • UV Curing: Ultraviolet light is used to cure specially formulated resins, offering rapid curing times (often less than 4 hours) and precise control (1).
   • Frontal Polymerization: A cutting-edge technique using a frontally curable epoxy resin that cures significantly faster than traditional methods with lower energy consumption (1).

2.2.4 Post-installation Inspection and Testing

After curing, comprehensive testing ensures the liner meets all performance requirements :

1. CCTV Inspection: A post-installation CCTV inspection verifies the liner's condition, looking for defects such as wrinkles, voids, or incomplete curing (12).
2. Pressure Testing: For pressure pipelines, hydrostatic testing is conducted to ensure the liner meets specified pressure ratings and is free from leaks (14).
3. Structural Integrity Testing: Various methods, including ring stiffness tests and impact-echo testing, are used to assess the liner's structural performance .
4. Flow Capacity Assessment: Laser profiling or flow monitoring may be used to ensure the rehabilitated pipeline maintains adequate hydraulic capacity (12).

The entire CIPP process typically takes 1-3 days for most applications, depending on factors such as pipe diameter, length, curing method, and site conditions (22).

III. International Standards and Regulatory Compliance

3.1 Key International Standards for CIPP Lining

CIPP lining technology must comply with various international standards that ensure consistent quality, performance, and safety across different applications and regions (1).

3.1.1 ASTM International Standards

ASTM International has developed several key standards governing CIPP lining materials and installation (1):

1. ASTM F1216 - Standard Practice for Rehabilitation of Existing Pipelines and Conduits by the Inversion and Curing of a Resin-Impregnated Tube: This standard specifies requirements for materials, design, installation, and testing of CIPP systems for non-pressure pipelines (1). It includes provisions for resin systems, carrier materials, installation procedures, and quality control.
2. ASTM F1743 - Standard Practice for Installation of Cured-in-Place Thermoset Liner for Rehabilitation of Existing Pipelines and Conduits: Focuses on pull-in-place installation methods, covering materials, equipment, procedures, and inspection (14).
3. ASTM F2897 - Standard Practice for Rehabilitation of Existing Pipelines and Conduits Using Cured-in-Place Pipe Lining with Light-Activated Resins: Specifically addresses UV-cured CIPP systems, including materials, installation, and performance requirements (1).
4. ASTM F3212 - Standard Practice for Rehabilitation of Existing Pipelines and Conduits Using Cured-in-Place Pipe Lining with Light-Activated Resins for Potable Water Applications: Provides additional requirements for CIPP systems used in potable water pipelines, including material safety and 卫生 standards (14).

3.1.2 ISO Standards

The International Organization for Standardization (ISO) has also established important standards for CIPP lining technology (1):

1. ISO 70115:2023 - Plastics piping systems for renovation of underground non-pressure drainage and sewerage networks: This standard specifies requirements for CIPP materials, design, installation, and testing for non-pressure drainage and sewerage applications (1). It covers both resin-impregnated and other types of liners.
2. ISO 21225-1:2018 - Plastics piping systems for the trenchless replacement of underground pipeline networks - Part 1: Replacement on the line by pipe bursting and pipe extraction: Although not specific to CIPP, this standard provides complementary guidance for trenchless pipeline replacement methods that may be used in conjunction with CIPP (39).
3. ISO 14050:2020 - Environmental management - Vocabulary: Provides definitions and terminology related to environmental management, which are increasingly important in assessing the sustainability of CIPP projects (18).

3.1.3 European Standards

In Europe, CIPP lining systems must comply with standards established by the European Committee for Standardization (CEN) (48):

1. EN 12816 - Rehabilitation of pipelines and ducts - Cured-in-place pipes (CIPP) - Part 1: Specifications for lining materials: Specifies requirements for materials used in CIPP systems, including resins, reinforcements, and carrier materials (48).
2. EN 12817 - Rehabilitation of pipelines and ducts - Cured-in-place pipes (CIPP) - Part 2: Specifications for work execution: Provides guidelines for the execution of CIPP lining projects, including planning, installation, and quality control (48).
3. EN 12007-4 - Gas infrastructure - Pipelines for maximum operating pressure up to and including 16 bar - Part 4: Specific functional requirements for renovation: Provides specific requirements for CIPP systems used in gas pipeline rehabilitation (39).

3.2 Quality Control and Performance Testing

To ensure compliance with international standards, rigorous quality control measures and performance testing are essential throughout the CIPP project lifecycle .

3.2.1 Material Testing

Before installation, all CIPP materials must undergo comprehensive testing to verify compliance with specified standards (16):

1. Resin Testing:
   • Viscosity testing to ensure proper impregnation and application properties
   • Gel time and cure time determination
   • Mechanical property testing (tensile strength, flexural strength, modulus)
   • Chemical resistance testing for specific applications (16)
2. Fabric/Reinforcement Testing:
   • Tensile strength and elongation
   • Weight per unit area
   • Dimensional stability
   • Resistance to chemical degradation (16)
3. Composite Testing:
   • Flexural strength and modulus of cured specimens
   • Impact resistance
   • Thermal stability
   • Water absorption characteristics (16)

3.2.2 In-situ Testing

During and after installation, various in-situ tests are conducted to assess the quality and performance of the CIPP liner :

1. Inner Balloon Pressure Test: A new test procedure that replicates the working stress conditions of an installed CIPP liner, providing a more accurate assessment of structural integrity than traditional methods . This test has been shown to reduce uncertainties related to strength analysis by up to 200% compared to the curved specimen bending test .
2. Burst Pressure Testing: Determines the maximum pressure capacity of pressure-rated CIPP liners, essential for ensuring safe operation in pressure pipeline applications (14).
3. Creep Testing: Assesses the long-term deformation characteristics of CIPP materials under sustained loading, critical for predicting 50-year performance (14).
4. Non-destructive Testing (NDT): Methods such as impact-echo testing, ground-penetrating radar, and impedance spectroscopy are used to detect delamination, voids, or other defects without damaging the liner (12).

3.2.3 Environmental Compliance

With increasing emphasis on sustainability and environmental protection, CIPP systems must also comply with relevant environmental standards and regulations (18):

1. VOC Emission Control: Styrene emissions from traditional CIPP systems have raised environmental concerns. Recent developments in styrene-free vinyl ester resins have significantly reduced VOC emissions, with measured concentrations as low as 2.54 ppm, well below OSHA and USEPA exposure limits (5).
2. Carbon Footprint Assessment: CIPP lining has been shown to reduce CO2 emissions by up to 70% compared to traditional open-cut methods, contributing to more sustainable infrastructure rehabilitation (48).
3. Life Cycle Assessment (LCA): Increasingly used to evaluate the environmental impacts of CIPP projects throughout their lifecycle, from material production to end-of-life disposal (18).

IV. Case Studies of CIPP Lining Applications

4.1 Large Diameter Sewer Rehabilitation in Phoenix, Arizona

The city of Phoenix, Arizona faced a critical challenge with a deteriorating 60-inch diameter steel water main in the Sonoran Desert (36). Given the scarcity of water resources in the region and the high costs associated with traditional excavation methods, the city selected CIPP slip lining as the most economical and efficient rehabilitation solution (36).

Project Details:

• Pipe Size: 60-inch diameter steel water main
• Length: Approximately 1 mile (1.6 km)
• Liner Material: 56-inch diameter steel liner pipe
• Installation Method: Slip lining
• Challenges: Extreme desert temperatures, high water pressure, and the need to maintain water service during rehabilitation (36)

Results:

• The CIPP slip lining system successfully restored the pipeline's structural integrity while maintaining full water service throughout the project
• The rehabilitation was completed in significantly less time and at lower cost than traditional open-cut replacement
• The new liner provided enhanced corrosion resistance and a projected service life of at least 50 years
• The smooth interior surface of the liner improved flow characteristics, reducing energy consumption for water distribution (36)

This project demonstrated that CIPP lining is a viable solution for large-diameter pipelines in challenging environmental conditions, offering substantial time and cost savings compared to conventional methods (36).

4.2 Stormwater Drain and Culvert Rehabilitation in Toronto, Canada

National Liner LLC recently completed an innovative CIPP rehabilitation project for stormwater drains and culverts in Toronto, Canada, using a styrene-free vinyl ester resin system with ultra-low VOC emissions (20).

Project Details:

• Application: Stormwater drains and culverts
• Liner Material: Styrene-free vinyl ester resin with glass fiber reinforcement
• Installation Method: CIPP with UV curing
• Environmental Considerations: Ultra-low VOC emissions, compliance with strict Canadian environmental regulations
• Design Life: 50-year engineered service life (20)

Results:

• The project successfully rehabilitated aging stormwater infrastructure with minimal environmental impact
• The styrene-free resin system significantly reduced volatile organic compound emissions, making it suitable for urban environments with strict air quality regulations
• The UV curing process accelerated project completion, reducing overall construction time by approximately 30% compared to traditional methods
• The CIPP liners achieved excellent structural performance, exceeding all design requirements for strength and durability (20)

This case study highlights the growing trend toward environmentally friendly CIPP systems that offer both technical performance and sustainability benefits (20).

4.3 Regional Heating Pipeline Rehabilitation in Stockholm, Sweden

Norrenergi AB faced a significant challenge when they identified a leaking district heating pipe beneath a busy road in Stockholm (4). Traditional replacement would have required extensive excavation, causing major disruption to traffic and businesses. Instead, they selected the CarboSeal™ CIPP system from Pressure Pipe Relining Sweden AB (PPR) for a trenchless rehabilitation solution (4).

Project Details:

• Application: District heating pipeline
• Challenges: Two expansion joints and a 12° curve in the section to be rehabilitated
• Liner Material: Specialized high-temperature resistant CIPP system
• Installation Team: Norrenergi AB (owner), Fjaerrvaermeprojekt Sverige AB (design and execution), Pollex AB (installation), PPR engineers (process control) (4)

Results:

• The CIPP lining successfully restored the pipeline without excavation, preserving the road infrastructure and minimizing traffic disruption
• The system effectively addressed the challenges of the expansion joints and curved section, demonstrating the versatility of CIPP technology
• The rehabilitation was completed in a fraction of the time required for traditional replacement methods
• The high-temperature resistant liner maintained structural integrity and thermal performance under operating conditions (4)

This case study illustrates the adaptability of CIPP lining technology for specialized applications beyond traditional sewer and water pipelines (4).

4.4 Polyethylene Pipe-CIPP Liner Composite Structure Research

A recent research project focused on evaluating the structural performance of CIPP liners installed within deformed polyethylene (PE) pipes, addressing a gap in knowledge that has limited the broader application of CIPP for PE pipe rehabilitation (3).

Research Details:

• Test Subjects: PE pipes with various diameter-to-wall thickness ratios (DR values)
• Test Conditions: External pressure loading to evaluate structural response and failure modes
• Variables Studied: Liner elastic modulus, bonding effectiveness at the PE pipe-CIPP liner interface, and initial pipe ovality (3)

Key Findings:

• CIPP liners significantly enhance the stiffness and load-bearing capacity of PE pipes, with improvements ranging from 200% to nearly 500% depending on the pipe's DR value
• The bonding effectiveness at the interface between the PE pipe and CIPP liner was found to be a critical factor in load transfer and overall system performance
• Initial pipe ovality had a measurable impact on the critical buckling pressure of the composite structure, with a 5% increase in ovality reducing critical buckling pressure by 10.62%
• A novel ring stiffness prediction model was developed and validated against experimental data, providing a theoretical framework for understanding complex interactions at the PE pipe-CIPP liner interface (3)

This research contributes valuable insights for engineers designing CIPP rehabilitation projects for PE pipes, which are increasingly common in modern water distribution systems (3).

V. Comparative Analysis of Pipeline Rehabilitation Technologies

5.1 Overview of Major Pipeline Rehabilitation Methods

Several trenchless pipeline rehabilitation technologies have been developed over the years, each with its own advantages and limitations (50). The most common methods include:

1. Cured-in-Place Pipe (CIPP) Lining: The focus of this guide, CIPP involves inserting a resin-impregnated liner into the host pipe and curing it in place to form a new structural pipe (31).
2. Slip Lining: One of the oldest trenchless techniques, slip lining involves inserting a new PE100 or PE100-RC liner pipe of standard diameter into an existing pipe. The new pipe has an outside dimension smaller than the host pipe's inside dimension (47).
3. Spray-in-Place Pipe (SIPP): Involves spraying a protective coating or structural lining directly onto the interior of the host pipe using specialized equipment (50).
4. Pipe Bursting/Explosive Replacement: A trenchless replacement method where a bursting head fractures the existing pipe while simultaneously pulling in a new pipe of equal or larger diameter (32).
5. Spiral Winding: A technique where a continuous strip of metal or plastic is wound inside the host pipe to form a new structural lining (24).
6. Point Repair: Targeted repairs for specific defects using localized CIPP patches or mechanical seals (26).

5.2 Comparative Analysis of Key Performance Criteria

The following table provides a comparative analysis of CIPP lining technology against other major pipeline rehabilitation methods across key performance criteria (24):

 

Performance Criterion	CIPP Lining	Slip Lining	Spray-in-Place (SIPP)	Pipe Bursting	Spiral Winding
Structural Restoration	Excellent - Forms fully structural liner	Good - New pipe provides structural support	Varies - Can be structural with sufficient thickness	Excellent - Replaces pipe with new structural pipe	Good - Provides structural reinforcement
Flow Capacity	Good - Slight reduction due to liner thickness	Very Good - Minimal reduction with close-fit liners	Excellent - Minimal thickness, smooth surface	Very Good - Can increase pipe diameter	Fair - May reduce diameter depending on design
Installation Speed	Moderate - 1-3 days for typical installations	Fast - Can install long sections quickly	Very Fast - Can complete 150m/day	Moderate - Depends on pipe size and soil conditions	Moderate - Installation rate varies with system
Application Flexibility	Excellent - Adapts to various pipe materials, sizes, and configurations	Good - Best for straight pipes with minimal bends	Excellent - Can handle complex geometries and varying diameters	Good - Can navigate some bends but limited by bursting head	Good - Can adapt to irregular shapes and offsets
Joint Sealing Capability	Excellent - Creates seamless liner, sealing all joints	Fair - Joints between liner segments may leak	Good - Can seal joints with proper application	Excellent - New pipe joints are typically watertight	Good - Continuous strip forms tight seal at joints
Cost Effectiveness	High - Reduced excavation and restoration costs offset material expenses	Very High - Simple technique with low equipment costs	High - Low material costs but specialized equipment required	Moderate - Higher equipment costs but can increase pipe size	Moderate - Material costs vary with system
Environmental Impact	Low - Minimal excavation, reduced traffic disruption	Low - Similar to CIPP	Low - Minimal waste generation	Moderate - Some surface disruption at entry/exit points	Low - Minimal site disturbance
Service Life	50+ years with proper design and materials	40-50 years depending on liner material	30-40 years for structural applications	50+ years with HDPE replacement pipe	40-50 years with quality materials
Pressure Rating Capability	Excellent - Can be designed for full pressure applications	Good - PE100 liners have high pressure ratings	Fair - Generally used for non-pressure applications	Excellent - New pipe can be rated for full pressure	Good - Can be designed for pressure applications
Specialized Equipment Requirements	High - Requires specialized inversion or pulling equipment and curing systems	Low - Simple pulling or pushing equipment	High - Requires specialized spraying equipment	High - Requires hydraulic bursting equipment	High - Requires specialized winding machinery

5.3 Comparative Analysis of Environmental Factors

Beyond technical performance, environmental considerations are increasingly important in selecting pipeline rehabilitation methods (18):

1. Carbon Footprint: CIPP lining has been shown to reduce CO2 emissions by up to 70% compared to traditional open-cut methods, making it a significantly more sustainable option (48).
2. VOC Emissions: Traditional CIPP systems using styrene-based resins can emit significant amounts of VOCs. However, recent developments in styrene-free vinyl ester resins have dramatically reduced this environmental impact, with emissions well below regulatory limits (5).
3. Waste Generation: CIPP lining generates minimal waste compared to pipe replacement methods, as the existing pipe remains in place and is rehabilitated rather than removed (18).
4. Energy Consumption: The energy requirements for CIPP curing vary depending on the method used. UV curing typically consumes less energy than hot water or steam curing, making it a more energy-efficient option (1).
5. Resource Conservation: By rehabilitating existing pipes rather than replacing them, CIPP lining conserves raw materials and reduces the energy-intensive manufacturing of new pipes (18).

5.4 Comparative Analysis of Economic Factors

Cost comparison is a critical factor in selecting pipeline rehabilitation methods (30):

1. Initial Costs: CIPP lining typically has higher initial material and equipment costs compared to some other trenchless methods like slip lining or point repair (30).
2. Life Cycle Costs: Despite higher initial costs, CIPP lining often provides lower life cycle costs due to its long service life (50+ years) and reduced maintenance requirements (22).
3. Disruption Costs: CIPP lining minimizes disruption to traffic, businesses, and residents, reducing indirect costs associated with project delays and inconvenience (30).
4. Restoration Costs: Traditional open-cut methods require significant restoration costs for landscaping, pavement, and other site features, which are largely eliminated with CIPP lining (34).
5. Downtime Costs: CIPP lining typically allows for faster return to service compared to open-cut methods, reducing costs associated with service interruptions (34).

5.5 Key Advantages of CIPP Lining Technology

Based on the comparative analysis, CIPP lining technology offers several distinct advantages that make it a preferred choice for many pipeline rehabilitation projects (22):

1. Structural Integrity: CIPP liners provide excellent structural reinforcement, effectively restoring or enhancing the load-bearing capacity of aging pipelines .
2. Seamless Construction: The cured liner forms a continuous, seamless pipe that completely seals all joints and defects in the host pipe, preventing infiltration and exfiltration (1).
3. Long Service Life: With proper design and installation, CIPP liners can provide 50+ years of service life, significantly extending the useful life of pipeline assets (22).
4. Versatility: CIPP technology can be used in a wide range of pipe materials, sizes, and configurations, including pipes with bends, offsets, and diameter changes (21).
5. Minimal Disruption: As a trenchless method, CIPP lining minimizes excavation, traffic disruption, and environmental impact compared to traditional open-cut methods (30).
6. Speed of Installation: While not the fastest trenchless method, CIPP can typically be installed and cured within 1-3 days for most applications, allowing for rapid return to service (22).
7. Design Flexibility: CIPP systems can be customized with different resin systems, reinforcements, and curing methods to meet specific project requirements for strength, chemical resistance, temperature tolerance, and other performance criteria (1).
8. Environmental Benefits: Modern CIPP systems with low-VOC resins and energy-efficient curing methods offer significant environmental advantages over traditional rehabilitation methods (5).
9. Cost Effectiveness: Despite higher initial costs, the combination of reduced disruption, lower life cycle costs, and extended service life often makes CIPP lining the most cost-effective option over the long term (30).
10. Proven Track Record: With over 50 years of successful applications worldwide, CIPP lining has established itself as a reliable and trusted pipeline rehabilitation technology (21).

VI. Emerging Trends and Future Developments

6.1 Advancements in Resin Technology

The development of new resin systems is driving significant improvements in CIPP lining technology (1):

1. Frontally Curable Epoxy Resins: Recent research has introduced frontally curable epoxy-based resins that cure significantly faster than traditional acrylate and vinyl ester systems while requiring lower irradiation dosages (1). These resins achieve higher glass transition temperatures and final monomer conversion, providing enhanced performance characteristics (1).
2. Styrene-Free Resins: To address environmental concerns about VOC emissions, styrene-free vinyl ester resins have been developed, offering ultra-low VOC emissions while maintaining excellent mechanical properties (5).
3. High-Temperature Resins: Specialized resin systems capable of withstanding elevated temperatures are being developed for applications in district heating, industrial processes, and other high-temperature environments (4).
4. Self-Healing Resins: Research into self-healing resin systems that can automatically repair microcracks and other minor damage is ongoing, potentially extending the service life of CIPP liners even further .

6.2 Innovations in Reinforcement Materials

Advancements in reinforcement materials are enhancing the structural performance of CIPP liners (16):

1. Fiber Reinforcement: The incorporation of glass fibers into CIPP liners has been shown to increase flexural strength by up to 13.3 times and flexural modulus by 8 times compared to traditional nonwoven fabric systems (16). This allows for reduced liner thickness while maintaining structural performance (16).
2. Hybrid Composites: The development of hybrid composite materials combining different types of fibers (such as glass and carbon) is creating CIPP liners with optimized strength-to-weight ratios and improved crack resistance (16).
3. Knitted Fabrics: New knitted fabric structures offer improved conformability to complex pipe geometries while maintaining high tensile strength and dimensional stability (16).

6.3 Curing Process Improvements

Curing technology continues to evolve, improving efficiency and performance (1):

1. UV Curing Advancements: Modern UV curing systems are incorporating more efficient LED light sources and improved light distribution systems, reducing curing times and energy consumption (1).
2. Combined Curing Methods: Hybrid systems that combine different curing methods (such as initial steam curing followed by UV curing) are being developed to optimize both speed and curing efficiency (14).
3. Smart Curing Control: Advanced monitoring and control systems are being implemented to ensure uniform curing throughout the liner, reducing the risk of undercured areas or thermal stress issues (1).

6.4 Digital Transformation and Smart Pipelines

The integration of digital technologies is revolutionizing pipeline rehabilitation (40):

1. Advanced Inspection Technologies: High-resolution CCTV, 3D laser profiling, and other advanced inspection tools are providing more detailed information about pipeline conditions, enabling more precise CIPP design and installation (40).
2. Digital Twins: The development of digital twin models that replicate physical pipelines and their CIPP liners is allowing for more accurate performance prediction and asset management (40).
3. IoT Monitoring: The integration of IoT sensors into CIPP liners is enabling real-time monitoring of structural performance, temperature, and other parameters, providing valuable data for maintenance and asset management decisions (40).
4. AI-Driven Design and Optimization: Artificial intelligence and machine learning algorithms are being applied to CIPP design and installation processes, optimizing material selection, curing parameters, and overall project planning (40).

6.5 Sustainability and Environmental Considerations

Sustainability is becoming an increasingly important focus for CIPP technology development (18):

1. Low-Carbon Materials: The development of resins and reinforcements with lower embodied carbon is a growing area of research, aimed at reducing the carbon footprint of CIPP systems (18).
2. Recyclable Materials: Research into recyclable CIPP materials is underway, addressing end-of-life concerns and promoting circular economy principles (18).
3. Energy-Efficient Processes: As mentioned earlier, advancements in curing technologies are reducing energy consumption during CIPP installation (1).
4. Life Cycle Assessment Integration: The incorporation of life cycle assessment (LCA) principles into CIPP system design is helping engineers make more sustainable material and process choices (18).

VII. Conclusion

Cured-in-Place Pipe (CIPP) lining technology has established itself as a leading trenchless rehabilitation method for drainage and other pipelines, offering numerous advantages over traditional open-cut methods (22). This comprehensive guide has provided engineering professionals with detailed insights into the technical principles, operational 流程，international standards, case studies, and comparative analysis of CIPP lining technology .

Key takeaways from this guide include:

1. Technical Excellence: CIPP lining provides excellent structural restoration, creating a new seamless pipe within the existing host pipe that can withstand external loads and internal pressures for 50+ years (22).
2. Operational Efficiency: The CIPP process involves several distinct phases - pre-installation preparation, liner fabrication and insertion, inflation and curing, and post-installation inspection - each requiring careful planning and execution to ensure successful outcomes (19).
3. Regulatory Compliance: CIPP lining must comply with various international standards, including ASTM F1216, ISO 70115, and EN 12816, which specify requirements for materials, design, installation, and testing (1).
4. Proven Applications: Case studies from around the world demonstrate the versatility of CIPP lining for various pipeline types, sizes, and applications, including large-diameter sewers, stormwater systems, district heating pipes, and polyethylene water mains (4).
5. Comparative Advantages: When compared to other trenchless rehabilitation methods such as slip lining, spray-in-place pipe, pipe bursting, and spiral winding, CIPP lining offers a favorable combination of structural performance, application flexibility, service life, and environmental benefits (24).
6. Ongoing Innovation: The future of CIPP lining technology includes advancements in resin chemistry, reinforcement materials, curing processes, digital integration, and sustainability, ensuring continued improvement in performance and environmental responsibility (1).

As urban infrastructure continues to age and the need for efficient rehabilitation methods grows, CIPP lining technology will play an increasingly important role in maintaining and extending the service life of critical pipeline systems (40). By combining technical excellence, environmental responsibility, and economic efficiency, CIPP lining represents a sustainable solution for the future of pipeline rehabilitation (18).

Engineering professionals involved in pipeline design, maintenance, and rehabilitation should consider CIPP lining as a primary option for trenchless rehabilitation projects, carefully evaluating its advantages against project-specific requirements and constraints . With proper planning, material selection, and installation, CIPP lining can provide a cost-effective, long-lasting solution that minimizes disruption while maximizing infrastructure performance and longevity (22).

reference material

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[8] 给排水管道非开挖垫衬誌再生修复施工新技术探讨 http://lib.cqvip.com/Qikan/Article/Detail?id=7002280549

[9] 一种管道“0”开挖无损修复技术 https://m.zhangqiaokeyan.com/academic-conference-cn_meeting-692_thesis/020221565929.html

[10] 64 Occupational exposure to styrene during cured-in-place pipe installations: An emerging issue https://academic.oup.com/annweh/article-abstract/68/Supplement_1/1/7700476?redirectedFrom=fulltext

[11] 经垫衬法修复后铸铁管道接口力学性能试验 http://m.qikan.cqvip.com/Article/ArticleDetail?id=7002034693

[12] Non-Destructive Characterization of Cured-in-Place Pipe Defects https://www.semanticscholar.org/paper/Non-Destructive-Characterization-of-Cured-in-Place-Dvo%C5%99%C3%A1k-Jakubka/f57345dfd9f155b33111bcb89541129ffd6dffbd

[13] 新型原位热塑成型管道非开挖修复技术应用案例 http://m.qikan.cqvip.com/Article/ArticleDetail?id=7104586296

[14] Cured-in-Place Pipe Pressure Liner Experimental Study https://uwspace.uwaterloo.ca/handle/10012/19254

[15] 非开挖垫衬法在市政给排水管道修复施工中的应用 http://m.qikan.cqvip.com/Article/ArticleDetail?id=668971566

[16] Short- and Long-Term Structural Characterization of Cured-in-Place Pipe Liner with Reinforced Glass Fiber Material https://pubmed.ncbi.nlm.nih.gov/32245052/

[17] 给排水工程不开挖翻衬法管道内衬修复技术分析 http://m.qikan.cqvip.com/Article/ArticleDetail?id=675437704

[18] Le changement climatique ajouté aux normes des systèmes de gestion | BSI https://www.bsigroup.com/fr-FR/themes/resilience-durable/changement-climatique-ajoute-normes-systemes-gestion/

[19] Evaluating CIPP Options for Large-Diameter Sewer Pipe Renewal https://www.battelle.org/insights/case-studies/case-study-details/evaluating-cipp-options-for-large-diameter-sewer-pipe-renewal

[20] Toronto Styrene-free CIPP Trenchless Pipe Lining & Rehab Case Study Announced - https://newswire.net/newsroom/pr/00259874-toronto-styrene-free-cipp-trenchless-pipe-lining-rehab-case-study-announced.html

[21] A Comprehensive Analysis of Environmental Emissions from Trenchless CIPP and Excavation Technologies for Sanitary Sewers https://www.mdpi.com/2076-3417/15/3/1268

[22] Extending the Lifespan of Storm Drainage Systems with CIPP - Advanced Pipe Repair https://www.advancedpiperepair.com/cipp-for-storm-drains/

[23] 管道材料修复方法 http://www.hndalu.com.cn/page1000045?article_id=347

[24] 给排水技术给排水管道非开挖垫衬法再生修复施工技术.pptx-原创力文档 https://m.book118.com/html/2024/0607/6105041143010142.shtm

[25] 管网改造施工_侃侃考证 http://m.toutiao.com/group/7519088206797767220/?upstream_biz=doubao

[26] 上海管道修复地下管道非开挖嵌补技术有哪些_非开挖修复技术-江苏捷安通环保科技有限公司手机版 https://m.chem17.com/st394244/product_32408505.html

[27] 雨污混接改造采用哪些施工方法?一起来看看_上观新闻 http://m.toutiao.com/group/7393709988495049226/?upstream_biz=doubao

[28] 管道修复采用哪种技术效果更好?-巍特环境_深圳巍特环境 http://m.toutiao.com/group/7108975724614599179/?upstream_biz=doubao

[29] 「管道非开挖修复」喷涂法优劣分析!_砂浆 https://m.sohu.com/a/322877583_120072189/

[30] The Cost Comparison Between Trenchless Pipe Repair And Traditional "Dig And Replace” Methods - PipeLT.com https://pipelt.com/sewer-repair/the-cost-comparison-between-trenchless-pipe-repair-and-traditional-dig-and-replace-methods/

[31] Trenchless Pipe Repair Techniques: Minimally Invasive Solutions - RTF | Rethinking The Future https://www.re-thinkingthefuture.com/technologies/gp1544-trenchless-pipe-repair-techniques-minimally-invasive-solutions/

[32] Trenchless Pipe Repair vs Traditional Pipe Repair | Plumb Works https://www.plumbworksinc.com/trenchless-pipe-repair-vs-traditional

[33] A Guide to Trenchless Pipe Repairs - Plumbing Nerds https://www.plumbingnerds.com/a-guide-to-trenchless-pipe-repairs/

[34] How Trenchless Pipe Replacement Differs From Traditional Methods https://thepipemedic.com/how-trenchless-pipe-replacement-differs-from-traditional-methods/

[35] Culvert Slip Lining System: An Ultimate Comparison of Methods and Benefits - Articly.ai Demo Blog https://blog.articly.ai/culvert-slip-lining-system-an-ultimate-comparison-of-methods-and-benefits-2/

[36] Case Study: Sliplining Water Main Saves Money and Time https://thompsonpipegroup.com/case-study-sliplining-water-main-saves-money-and-time/

[37] Documents - Runway Drainage Pipe Sliplined (South Haven, MI) Case Study https://www.adspipe.com/resources/documents/E49D326C-DC97-4E21-98B2A4A1D1B36FA3

[38] Slip Lining - PW Trenchless https://www.pwtrenchless.com/projects-by-methodology/slip-lining/

[39] ISO 21225-1:2018(en), Plastics piping systems for the trenchless replacement of underground pipeline networks — Part 1: Replacement on the line by pipe bursting and pipe extraction https://www.iso.org/obp/ui/#!iso:std:70113:en

[40] The Pulse of the Trenchless Rehab Market in 2025 | Trenchless Technology https://trenchlesstechnology.com/the-pulse-of-the-trenchless-rehab-market-in-2025/

[41] Trenchless Pipe Rehabilitation Market Report 2025, Share & Statistics https://www.thebusinessresearchcompany.com/report/trenchless-pipe-rehabilitation-global-market-report

[42] Pipe Rehabilitation | Seals & Profiles https://www.trelleborg.com/en/seals-and-profiles/products-and-solutions/pipe-rehabilitation

[43] ISO/TR 7015:2023 - Ergonomics — The application of ISO/TR 12295, ISO 11226, the ISO 11228 series and ISO/TR 23476 in the construction sector (civil construction) https://www.iso.org/standard/82525.html

[44] ISO - International Organization for Standardization https://www.iso.org/home.html

[45] Manufacturing Certifications​ Of Bags You Need To Know 2025 https://www.leelinebags.com/manufacturing-certifications/

[46] Trenchless method for the rehabilitation of pipelines: Primus Line https://www.primusline.com/en/installation/trenchless-method

[47] Pipe Rehabilitation Methods - HDPE pipe systems (plastic & polyethylene pipe) - PE100+ association https://www.pe100plus.com/PE-Pipes/Technical-guidance/Trenchless/Methods/Pipe-Rehabilitation/r1102.html

[48] TRENCHLESS REHAB OF PRESSURE PIPES - Trenchless Works https://www.trenchless-works.com/trenchless-rehabilitation-of-pressure-pipes/

[49] Trenchless Rehabilitation Evaluation: How to Properly Inspect and Locate Damaged Pipelines https://trenchlesspedia.com/evaluating-existing-conditions-that-indicate-the-need-for-rehabilitation/2/3723

[50] Trenchless Technologies Improve for Pipeline Rrehabilitation – Architecture . Construction . Engineering . Property https://sourceable.net/trenchless-technologies-allow-for-pipeline-rehabilitation/