Anomaly Description:
Underground piping was inspected and it was found that two valves in close proximity to each other had extensive corrosion on the body and bolting. The header piping is 2” and branches out the valve to 3”. The remaining wall thicknesses of piping between the valves were also below thickness specification.

Root causes:
Piping being underground and having damaged and missing paint coatings.

Integrity concerns:
The remaining thickness of underground sections were below the minimum allowable value which posed the risk that leaks may occur in the near future that could result in possible environmental contamination due to loss of containment.

Clamp Design:
A straight line enclosure with two nozzles was designed to encapsulate both valves. Strongbacks were designed to contain the complete system in the event that complete failure of piping welds or valve bolting occurs.

Seal:
Due to the enclosure being underground; a polymer sealant injection would potentially cause problems. Should the enclosure start leaking and the enclosure need to be re-injected, no visible signs of a leak would be evident. Therefore, a two-part thermosetting resin was employed to fill the complete cavity of the enclosure and encase the piping and the valves within the enclosure. This boasts a more permanent repair and eliminates the enclosure leaking underground if the need fo a re-injection arose.