Organic “High-Build” Spray-in-Place Liners – An Emerging Class of Rehabilitation Methods

By Erez N. Allouche, PhD, P. Eng. and Eric J. Steward, Trenchless Technology Center, Louisiana Tech University | June 2009 Vol. 64 No. 6

In March 2009, TEP undertook the relining of the water pipe intake of Unit 1 (a 380 megawatt generating system). The project consisted of relining 1,800 feet of 96-inch and 620 feet of 72-inch steel pipe. TEPs representatives contacted Innovative Painting & Waterproofing, an Arizona-licensed contractor based in Brea CA, for replacing the existing mortar lining with 60 mils (1.5 mm) of polyurea coating. Innovative was retained to apply the polyurea lining using a combination of robotic plural-component spray equipment (designed and developed in-house in cooperation with the Trenchless Technology Center; see Figure 13) and hand-spray methods in areas inaccessible to the robotic systems.

The Graco/Gusmer material pumps used for the project utilized the latest data recorder and flow meter tracking hardware and software, providing real-time and historical pressure, temperature, flow and other critical data. Hartman Walsh Corporation was retained to handle the demolition of the existing mortar lining and perform hydro/abrasive blasting of the pipe’s interior surfaces. The entire project was set for completion within a tight 4-week window during a pre-scheduled 5-week shutdown of Unit 1.

To complete the project within the allotted time required Innovative to operate around the clock for part of the project duration. The project was completed on time and budget.

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Fig 13. A robotic unit used to apply a 60 mil polyurea coating to nearly half a mile of 96” and 72” steel pipe.

Rehabilitation of a 60-inch CMP culvert