$500K+ saved inspecting 26 refinery stacks without shutdown

The challenge

A Kansas petroleum refinery needed to inspect 26 stacks for corrosion, wall thinning, and structural integrity. Conventional methods required erecting scaffolding around each stack, deploying rope-access technicians, and taking the units offline during inspection — a process that typically consumed three weeks and required full production shutdowns. Each shutdown day represented significant lost revenue on top of the direct inspection costs.

The method

The solution

The Voliro drone used magnetic adhesion to land on and crawl along each stack’s exterior surface, pressing ultrasonic thickness sensors directly against the metal at predetermined grid points. This contact-based approach delivered the same data quality as manual UT measurements — wall thickness readings accurate to 0.1mm — without requiring human access to height. Visual inspection cameras simultaneously captured high-resolution imagery of welds, coatings, and surface conditions.

The results

All 26 stacks were inspected in 2 days — compared to the 3-week timeline required for conventional scaffolding and rope-access methods. Total savings exceeded $500,000, driven primarily by eliminated scaffolding costs, reduced crew mobilization, and zero production downtime. The facility continued operating at full capacity throughout the inspection campaign.

Beyond cost savings, the drone approach eliminated confined-space entry risk and work-at-height exposure for inspection technicians — two of the highest-risk activities in refinery maintenance. Data was delivered in a format compatible with the facility’s existing asset integrity management system.