Specification:

For tubesheets and waterboxes, we specify the NHECC Cladding System, which results in the precise application of 200 mils DFT (±40 mils) of high performance, 100% solids (non-solvent emitting) epoxy materials. The NHECC supplied materials will consist of the NHE100 as the primer coating, the NHE200 as the build-up coat, and NHE100 as the top coat.

Scope of Work:

•  High-pressure water-blast tube sheets and tube ends for decontamination of the substrate and     initial surface preparation.
•  Flare all tube ends.
•  Dry heat exchanger tube sheets.
•  Plug tube ID's with caps.
•  Surface prep by abrasive blasting (3 mil profile minimum with good angularity and density to     NACE 1 or SSPC-SP-5).
•  Environmental control, using desiccant bed dehumidifiers with inline heaters and dust collectors.
•  Remove abrasive blasting protective caps, replacing with plugs to protect tube ID's from cladding     process.
•  Application of cladding materials.
•  Apply NHE100 primer coat and allow 8 to 12 hrs to cure.
•  Apply NHE200 build-up to fill in all voids and allow 8 to 12 hrs to cure.
•  Sand build-up coat to a smooth finish.
•  Apply NHE100 as finish coat and allow 12hrs to cure.
•  Clear tube ends of plugs and any residual debris.

Advantages of the NHECC System

•  The NHECC Cladding System for tubesheets and waterboxes is distinguished by its thick film nature of 100% solids epoxy materials that offer unparalleled protection. Advantages of this system for main surface condenser and heat exchanger tubesheets and waterboxes, down tube coatings, waterbox/channel heads, and circulating water piping include:

•  Restores tube-to-tubesheet joint strength providing a 100% assurance of "leak free" joints.
•  Resilient flexing, allowing movement at the tubesheets operational service bending/deflection modes without cracking.
•  Resistant to wear and tear associated with turbulence and erosion often present at tubesheet and waterbox surfaces.
•  Resistance to impact and workman damage occurring during the cleaning of condensers, tube plugging, and scaffolding efforts.
•  Inert to chemical cleaning and water treatment programs.
•  Assist in identifying tube leaks much faster and more successfully once tube-to-tubesheet leaks are eliminated.