In-Place Asbestos Concrete Pipe Encapsulation With HDPE Liner
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Solution Overview
Problem
Underground asbestos concrete pipes face structural integrity issues, leading to leakage, blockages, and health risks due to asbestos contamination, requiring costly and labor-intensive removal and replacement, especially in challenging coastal environments with high water tables and wet conditions.
Innovation Solution
A method and system for in-place encapsulation using a scribing head with progressively increasing blades to separate the pipe, followed by the application of a moisture-activated expanding urethane foam reinforcement material to encapsulate the asbestos, allowing a new HDPE pipe to be pulled in and glued to the old pipe, eliminating the need for excavation and hazardous material disposal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If asbestos concrete pipes are removed and replaced with new pipes, then the structural integrity and flow specification are restored, but extensive excavation is required resulting in large-scale construction, many man-hours, and high construction cost
Solution Approach 1:
The patent extracts the problematic asbestos material from the pipe structure through selective removal of the asbestos-cement lining while preserving the underlying concrete pipe. This allows restoration of structural integrity without complete pipe replacement, avoiding extensive excavation and reducing construction time and costs
Solution Approach 2:
The patent implements a nested structure by placing a new structural liner inside the existing concrete pipe. The new HDPE pipe is inserted within the old pipe structure, creating a nested configuration that restores functionality while minimizing disruption to the surrounding environment and reducing excavation requirements
2Reliability
If asbestos-containing pipes are removed by digging a ditch and manually picking up sections, then the pipes are replaced, but asbestos may become airborne creating health risks and requiring hazardous waste disposal
Solution Approach 1:
The patent converts the harmful asbestos-containing pipe into a beneficial situation by encapsulating the asbestos material within the new structural liner and sealing it in place. The asbestos is transformed from a removable hazardous waste requiring disposal into a contained element that is sealed and isolated, eliminating airborne risks while maintaining pipe functionality
Solution Approach 2:
The patent introduces a new structural liner as an intermediary barrier between the asbestos-containing old pipe and the environment. This liner acts as a mediator that encapsulates the hazardous asbestos material, preventing asbestos fibers from becoming airborne and eliminating the need for hazardous waste disposal while restoring pipe functionality
3Reliability
If asbestos pipes are dismantled by crushing the casing with a chipping machine, then the pipe is removed, but it takes considerable time and labor and asbestos scattering cannot be completely prevented
Solution Approach 1:
The patent inverts the conventional approach by instead of removing the old pipe through crushing and dismantling, it pulls the new HDPE pipe through the existing old pipe from one end to the other. This inversion of the process sequence eliminates time-consuming excavation and manual dismantling operations while containing asbestos within the old pipe structure throughout the process
4Reliability
If pipes are removed in coastal communities with high water tables and tidal influences, then replacement is possible, but digging becomes virtually impossible below 8-10 feet depth due to wet conditions
Solution Approach 1:
The patent performs preliminary action by preparing and positioning the new HDPE pipe section on land before inserting it into the old pipe. The new pipe is pulled through the existing pipe structure from an accessible endpoint, avoiding the need for excavation in the difficult coastal terrain. This preliminary preparation eliminates the feasibility problems associated with deep excavation in wet, tidal conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables safe, economical, and environmentally friendly reinforcement of asbestos-containing pipes without disrupting the surrounding ecosystem, reducing construction costs and minimizing health risks by keeping the pipes in place, with minimal community disruption and no hazardous material disposal requirements.
Implementation Method 1
application of a moisture-activated expanding urethane foam reinforcement material to encapsulate the asbestos
Data Source
AI summary
A process and system is provided to allow rehabilitation of asbestos concrete (AC) pipe to remain in place while rendering the AC pipe harmless, in a manner that protects the ecosystem and saves huge amounts of money lost to bypass, digging, remediation and disposal. The method and system provide for encapsulation of the old AC pipe in place without any digging or disruption to the surrounding area. No dewatering is required, saving the costs required with dewatering. There is minimal disruption to the community's use of the piping system while completing the repair, as such repairs can be done on a manhole-to-manhole basis. Finally, there are no hazardous material disposal requirements, or the costs associated therewith.