Epoxytec:

Your I&I Solution for Manholes

Your Trusted Experts for Comprehensive I&I Solutions in Sanitary Sewer Manholes

As I&I experts, Epoxytec representatives have the experience and expertise to provide inflow and infiltration (I&I) solutions for sanitary sewer manholes. With decades of experience, Epoxytec’s products are proven to protect against the harsh and harmful effects of I&I.

An Introduction to Inflow and Infiltration (I&I)

Most buried assets in sanitary sewer systems are concrete, brick, or masonry, acting like sponges that absorb water over time, leading to issues like cracks and damage. Inflow and infiltration (I&I) occur when clean water from stormwater or groundwater enters sewer systems through deteriorated concrete, cracks, or faulty seals. This water can overwhelm treatment plants and cause sewage overflows. Aging infrastructure and corrosion from substances like hydrosulfuric acid worsen these problems, leading to costly repairs. Trenchless solutions for rehabilitating and lining collection systems are crucial for addressing these issues. Ignoring I&I can lead to environmental and financial consequences, including the need to expand treatment plants.

The Rise of I&I Abatement Programs

The ASCE’s “US Infrastructure Report Card” gives wastewater infrastructure in the US a grade of D+. However, 62% of surveyed utilities have shifted to proactive maintenance thanks to asset management plans, crucial for addressing issues before corrosion and I&I affect sewer systems. The EPA emphasizes the importance of I&I abatement programs, outlining goals to reduce costs, minimize liability, avoid plant and interceptor expansion costs, and offset environmental impacts. Municipalities are pursuing various funding opportunities and allocating resources from their budgets to address these challenges comprehensively.

Trenchless Approach to Providing a Targeted Solution

Identifying the sources of I&I and understanding the factors causing the issue is crucial for selecting the right solution. Not all sewer lines require the same approach, so solutions should align with the specific needs of the system. Trenchless methods offer innovative and proven lining techniques to address EPA mandates and municipal I&I goals effectively, without the need for costly dig-and-replace methods. These methods:

comply with mandates
protect public health and the environment
optimize taxpayer funds
delay infrastructure expansion
extend the life cycle of assets

Solutions for vertical structures like manholes should be carefully chosen based on factors like environment and severity of I&I, with consultation from an experienced, professional.

Condition Assessment

When dealing with I&I, the first crucial step is a comprehensive condition assessment to understand the impact of corrosion and leaks. This assessment is essential for proactive I&I abatement or reacting to mandates like EPA consent decrees. Effective planning and execution depend on collecting relevant data, understanding which assets contribute most to I&I, why they occur, and anticipating future challenges. Organizations like WEF, AWWA, NASTT, NASSCO, EPA, AASHTO, and AMPP provide guidance on I&I and trenchless lining options, including standards and education. After assessment, a plan can be formulated to target specific structures.

Distinctions in Underground Buried Assets

Lining methods are successful when using products designed for monolithic watertight sealing to mitigate I&I. It’s crucial that technologies for lining both horizontal and vertical structures can interface effectively to deliver seamless monolithic linings.

When evaluating buried collection lining systems, consider two main categories: horizontal pipe systems and vertical assets like manholes and pump stations. Each category experiences distinct forces and stresses, often requiring different technologies and performance requirements. For example, horizontal pipe liners may need greater strength and wall thickness to bear load or resist internal pressure, while manholes may require film thickness mainly to hold back I&I.

Various manhole rehab and lining options offer benefits based on specific situations:

For cost-effectiveness in low I&I situations, cementitious linings may be suitable due to inexpensive materials and ease of application.
For high I&I situations requiring a comprehensive, vacuum-tested, sealed monolithic system, advanced technologies like ultra-high build, high-strength, bonded polymer lining systems are ideal. These systems integrate seamlessly with other pipe lining technologies and bond well to avoid annular space and interfaces. Epoxy polymer liners, such as Epoxytec CPP, are designed for optimal bonding and tying in vertical assets to horizontal pipes.

Horizontal Pipe Lining

Horizontal pipe lining can be achieved using various proven technologies.

Cured-in-place pipe (CIPP) and pull-in-place lining are commonly used for large projects and long lengths due to their cost-effectiveness in preserving existing pipes damaged by leaks, cracks, roots, and corrosion.

Pipe bursting is used on severely damaged pipes, for replacing entire systems, or repairing larger sections. It involves placing a “bursting head” at one end of the pipe and using hydraulic power to drag it through, breaking the old pipe and drawing a new one behind it.

Sliplining is an older method for rehabilitating pipelines, used to repair leaks or restore structural stability. It involves installing a smaller “carrier pipe” into a larger “host pipe,” grouting the space between, and sealing the ends. Materials like high-density polyethylene (HDPE), fiberglass-reinforced pipe (FRP), or PVC are common for sliplining.

Spray-in-place pipe (SIPP) lining uses high-build, high-strength polymer systems to fill cracks and imperfections, creating a watertight seal once cured. SIPP is suitable for irregular pipes or shorter runs where other methods may be limited.

Vertical Lining (manholes, wet wells, lift/pump stations)

The buried forces affecting vertical structures differ, requiring a diverse range of lining solutions. These solutions vary due to distinct conditions and lining intentions, and are distinct from those associated with horizontal pipe lining.

Certain liners aim to prevent hydrogen sulfide (H₂S) corrosion as the main design parameter. However, when the project requires more than corrosion protection—specifically, resistance to and mitigation of I&I forces like hydrostatic pressure—a watertight, monolithic high-strength liner is essential.

Vertical manhole lining, though not as high strength as horizontal pipe lining, confronts distinct forces, such as effective lateral earth forces and hydrostatic pressure which are lower pressure forces. This technology is typically applied and bonded to endure these pressures unique to vertical assets.

Applied Polymer Lining – Why Bond Strength Matters

For true monolithic watertight solutions for vertical structures like manholes, wet wells, and lift stations, selecting a bonded technology is crucial. Strong adhesion not only to the host but also to other liners for seamless transitions is essential. Bonded systems reduce the risk of annulus formation, stopping hydrostatic pressure and water migration, ensuring long-term sealing of horizontal and vertical linings fused together.

Bonded systems are optimal for I&I mitigation, holding back pressure without annulus formation and bonding well with various construction materials and adjacent liners like CIPP. This results in vacuum-verified, true monolithic, watertight systems from manhole to manhole.

When evaluating bonded systems, delve into actual bond strength data and ensure compatibility with manhole environments and construction materials. Testing standards like those from the University of Houston’s CIGMAT program and the US EPA Environmental Technology Verification protocol provide valuable insights. Epoxy-amine resins are commonly used for bonded lining systems due to their versatility and rapid self-repair capabilities. Systems with high film builds and robust strengths, known as “Ultra-High-Build, High-Strength Epoxy,” are often specified for various applications, including manhole and lift station linings.

Key Attributes of a Fully Sealed Monolithic Solution

Key Attributes of a Fully Sealed Monolithic Solution:

Adhesion to Various Materials: The liner should bond strongly to materials like CIPP, clay, brick, concrete, and steel.
High Film Thickness: A substantial wall thickness enhances durability (measured as Dry Film Thickness).
High Flexural and Tensile Strengths: Elevated flexural and tensile strengths are crucial, with less emphasis on compressive strength.
Vacuum Test Compatibility: The liner should withstand vacuum testing for a reliable, airtight seal.
H2S Resistance: Adequate resistance to hydrogen sulfide (H2S) is necessary for wastewater environments.
Repairability and Maintainability: The liner should be easy to repair and maintain without complex equipment.
High Bond Strength with Zero Annulus Design: It must have high bond strength to prevent annulus formation, ensuring a seamless, watertight connection.
Resistance to Root Intrusion, Hydrostatic Pressure, and Water Infiltration: The liner’s high-strength film should resist root intrusion, hydrostatic pressure, and water infiltration, ensuring continued structural integrity and preventing leaks.

Benefits of Applied and Bonded, Ultra-high Build, High strength epoxies

Zero Annulus Design: The epoxy system’s design and polymer type prevent annular space formation, enhancing the lining system’s integrity and eliminating vulnerabilities.
Versatility in Tie-In: The system easily ties into various construction materials, including cured-in-place pipe and other liners, making it suitable for diverse environments and projects.
High Repairability and Maintainability: The epoxy system allows for easy repair and maintenance without complex equipment, minimizing downtime and operational disruptions.
High Surface Tolerance: Epoxy systems have high surface tolerance, enabling effective application and adhesion to different substrate conditions for long-lasting performance.
Good “Wet” (SSD) Adhesion: Epoxy systems show good adhesion to wet surfaces, ensuring reliable performance in moist environments.
High Flexural and Tensile Strengths: Structural epoxy systems have high flexural and tensile strengths, providing resistance to side wall pressures and maintaining structural integrity.
Epoxy-amine resins are key to providing durable, long-lasting, structurally sound solutions in challenging environments.