Routine borescope inspection identified debris and corrosion at the bottom of several installed ball valve cavities, exceeding the applicable acceptance criteria. Workshop overhaul could have required shutdown, valve removal and reinstallation, crane access, transport, dismantling, cleaning, replacement parts, reassembly and testing. Restricted access made this conventional approach particularly disruptive and costly.
The objective was to restore cavity cleanliness while the valves remained installed. After reviewing the procedure and valve components for product compatibility, CGS developed an in-situ flushing approach.
The vent and drain ports created a controlled flow path through suitable valves. Using a tapped blind, hoses, gauge, filter and diaphragm pump, VpCI®-422 was introduced, retained and circulated to loosen debris and remove corrosion. The cavity was then drained, checked by borescope and retreated if necessary.
After corrosion removal, the valve was flushed with VpCI®-418 and water. Its non-foaming formulation supported clear borescope inspection, while residual VpCI®-418 could remain in the sealed cavity for ongoing vapour-phase corrosion protection.
The key constraint was achieving sufficient flow without releasing the valve seat. Valves above 10 inches typically have flanged ports, while smaller valves may have only a 1/2-inch NPT plug. Pressure and pump speed were therefore adjusted under valve technician guidance. A JHA, permit, SDS, PPE, spill kits, new gaskets and baseline borescope inspection were required before work began.
The successful trial demonstrated that installed ball valve cavities could be cleaned, preserved and re-inspected without the need for workshop removal or refurbishment. Following the initial success, the methodology was applied to more than 800 ball valves, delivering multi-million-dollar cost savings for the client. By avoiding valve removal, refurbishment, transportation, crane lifts, reinstallation activities and associated production losses, the project significantly reduced operational disruption while maintaining asset integrity and reliability.
Where inspection confirms suitability, this approach can minimize downtime by eliminating or postponing shutdown, lifting, transport and overhaul activities. For future applications, pH levels should be monitored periodically to verify product effectiveness, and spent solution should be discarded as required. Once cleanliness meets the acceptance criteria, vent and drain blinds should be installed immediately to retain the protective VCI atmosphere. A representative sample of preserved valves should then undergo follow-up borescope inspection after two to three months to verify continued corrosion protection.
