Centrifugally Cast in Place Liner Systems (CCPLS) Pipe Renewal and Protective Coatings
Technical Guidelines & Specification
Pipe may be repaired or rehabilitated by centrifugally casting cementitous structural repair mortars and epoxy materials in order to reline existing pipe to a new monolithic uniformed casting which can restore or enhance structural integrity and/or corrosive protection. Pipe can be damaged for a number of reasons but not limited to the following, dynamic loading, abrasion, erosion, and corrosion or the pipe has exceeded its design life. Using cementitious and/or epoxy materials in this manner can successfully procure metal pipe, clay pipe, concrete pipe, and many other forms of pipe, quickly, safely, and efficiently. To ensure any form of quality assurance it is the Owner/ Design Engineer’s responsibility to properly evaluate the proposed cementitious and epoxy materials as well as the qualifications of the installer/applicator performing the work. The State of Texas has already accepted these materials in their TCEQ chapter 217 design criteria for wastewater system applications in its Section 217.56 Trenchless Pipe Installation C1 Cement Mortar Lining and C2 Epoxy Lining page 45. Southern Trenchless has developed its own proprietary method called InsituCast™ Lining System for this special and unique internal relining/renewal process.
1.0 Installation Overview Instructions
This specification will describe how these materials can be centrifugally casted into place in order to achieve a uniform inner liner that will adhere, cure, and provide a long term permanent upgrade or repair for existing underground pipe.
2.0 Surface Preparation
Once the surface preparation of the pipe has been completed based on pipe material requirements (see surface prep standards from SSPC, NACE, ASTM and/or manufactures recommendations) then it is ready to receive which ever material or materials has been pre-determined to be installed at the pre-determined thickness required.
3.0 Install Process
Applicator shall place equipment into position in order to start the application process. Spin cast nozzle shall be placed in the center point of the pipe to ensure even and uniformed build of material on a skid or mobile apparatus that will keep the nozzle stable and centered during the application process. Once equipment is inside the pipe the spin casting equipment can be pulled or pushed in a forward or reverse direction by a cable wench system, pulley system, manual rope system, and robotically controlled. If the equipment has to be shut down or stopped prematurely during the application process restart the application process where it was last stopped and overlap the last termination point to continue a seamless uniform and monolithic liner. Materials will be supplied to spin cast nozzle by pumps that can handle specified material through correctly rated and sized hose line.
4.0 Install QC
Gauges or pre-installed dowels can be inserted prior to coating process to QC that the material is building to the desired thickness and live or recorded video can be captured during the install so that a visual inspection can prove that material is achieving desired coverage of the surface area to be relined. Calculated pumping speed and rate of build can also determine material thickness is being achieved through mathematical calculations (material used, time, material thickness, and diameter of pipe). Once material has been properly installed and cured out based on manufactures recommendation the pipe can then be returned to service once all flow control devices and/or pumps can also be removed and normal return to service can take place. Since this is a unique application other quality control measures may be implemented as deemed necessary.
5.0 Reapply or Touch Up
Follow product manufactures specification for cured and uncured recoat times and procedures. This step is VERY IMPORTANT and a qualified applicator should perform this procedure if deemed necessary.
Inspections should be done by certified and trained inspector for this specialized scope of work. Owner/ Design Engineer shall appoint someone who meets or exceeds these criteria in order ensure proper QC measures and documentation of the work is being properly executed as intended.
Safety is the most important aspect in this process and must be considered prior to any work being performed. This system actually eliminates many safety factors by utilizing remote automated mechanical equipment inside of the pipe so it limits most human exposure to work related hazards associated with this type of work. IF any personnel should have to enter the work area OSHA confined space and/or any other safety precautions deemed necessary should be identified and implemented as required.
Sustainability, practicality, and cost effectiveness are all factors that have evolved this process to accommodate industry needs. If these guidelines/steps are properly carried out as described in this specification a long lasting permanent rehabilitation will extend the service life of the existing pipe well beyond its original design life. Trenchless Technology is and will be the future of maintaining underground infrastructure as it grows and ages.