Drone vs Stack Inspector at Oil Refineries: Which Fits?

Is a drone vs stack inspector choice worth it at an oil refinery?

A drone is worth considering when the inspection is mainly visual. Stack shells, flare tips, platforms, ladders and markings can often be photographed from a camera flown around the structure, which removes much of the climbing, rope access and scaffold work that crews otherwise do. That is the core of the drone vs stack inspector question: how much of the job is seeing the structure, and how much is touching it.

The drone makes less sense when the scope depends on contact. Wall thickness checks, internal inspection, hot work and any finding that needs a person on the structure still need a qualified stack inspector. It also adds little for a one-time look at a short stack, because setup, flight planning and image review take time that a small job does not repay.

Most refineries will land on a split: drone for survey and imaging, a smaller crew for contact work and sign-off. Treat that as a hypothesis to test on a few stacks, not a settled answer.

What does a stack inspector actually do during a shift?

A stack inspector's day is built around access. Before anyone climbs or rigs a structure, the crew confirms the work permit, the flare or isolation status, the wind and the work zone, then sets up rope access, scaffold or a lift. Only after access is secure does the visual inspection begin, with the inspector working around the shell, platform, ladder, flare tip and any visible damage.

The visual part is slow for reasons that have little to do with looking. Each section of a structure needs its own access setup, and the inspector must record findings, photograph defects and mark locations as the work goes. Public figures for hours per shift or stacks per crew were not found in this review, so the site's own records should set those numbers.

Which parts of a stack inspection can a drone take, and which can it not?

A drone does best on work that depends on seeing the whole structure from several angles. It can capture shell condition, coating breakdown, platform and ladder damage, flare tip condition and visible signs of leaks or deposits, without anyone climbing the stack. Vendors describe removing the need for climbers and rope access at height, and that is the practical gain to test.

It cannot make contact measurements. Thickness readings, hardness tests and internal condition checks need a sensor or a person on or inside the structure, so those stay with the crew. Image quality also depends on light, weather and gas plume conditions, and a flight near an active flare is a decision for the site, not for the pilot.

• Shell and coating condition from several angles
• Platform, ladder and handrail defects
• Flare tip condition, when the site allows the flight
• Markings, labels and visible leaks or deposits
• Not included: wall thickness, hardness, internal walls and hot work

How many refineries and workers are in this market?

The US refining base is smaller than many people assume, and that shapes how many sites a drone program would serve. According to EIA's refinery capacity report, as of January 1, 2026, there were 130 operable petroleum refineries in the US. A third-party listing cites 132, but it is older and less authoritative, so use the EIA count.

The people who run refinery units are counted separately. According to BLS data for 2024, as summarized in its industry profile, about 20,420 people worked as petroleum pump system operators, refinery operators and gaugers. That occupation is not the same as a stack inspector, and the BLS figure does not show how many of them do stack work, so a site should count its own inspection roles.

Turnover, overtime, night shifts and sick days for refinery inspection crews were not found in this review. The federal turnover series may not break out this industry code, so the site's own shift and attendance records are the better source before any staffing model is built.

How safe is refinery work, and what do the injury rates show?

Refinery work shows a lower injury rate than manufacturing in API's figures, but those figures cover the whole refinery workforce, not stack crews. API's 2024 Workplace Safety Report puts the nonfatal injury and illness rate for US refinery workers at 0.4 per 100 full-time workers, against 2.7 for US manufacturing. API notes its own definition may differ from the total recordable rate.

The trend in API's reports also runs downward. Its 2017 report, citing BLS, gave 0.7 per 100 full-time workers for refineries against 3.5 for manufacturing. A BLS industry page for NAICS 3241, which covers petroleum and coal products, lists a total recordable case rate of 1.0 per 100 full-time workers and a days-away rate of 0.4.

Fatal injuries are rare but real. The BLS page shows 9 and 7 fatalities for the operator occupation in the two most recent years it lists, and those years are not clearly labeled in the summary. Work at height is one of the risks a drone is meant to reduce, but no peer-reviewed study in this review measured how much.

How long does a drone stack inspection take compared with a crew?

Most published timing comes from vendors, so read it as a claim to test rather than a measured result. An undated Cyberhawk document reports total inspection time cut from weeks to 5 days, with flare inspection described as taking months when done conventionally. The same document describes five flares inspected in under one week while the units stayed fully operational, which avoided a shutdown.

Other vendor figures point the same way with less detail. A 2019 Terra Drone blog post describes six high structures inspected over four days. An Acuren and Voliro case study at a Kansas refinery reports 26 stack inspections at 2 to 3 stacks per day and describes the work as three times faster than conventional methods. An iFactory page describes a flare inspection that took three days with a crane and scaffold crew and now takes two hours with a drone and a two-person team, and calls it 75 percent faster than rope access, though its figures vary across its pages.

No peer-reviewed study comparing drone and crew hours per stack was found, so the timing gap is plausible but not independently established. Timing matters most when a shutdown or turnaround window is the real constraint, and that is a question for your own schedule.

How does a team work with a drone, and is zero staff ever the answer?

Zero staff is never the right answer at a refinery. A drone plan still needs a pilot, a person who reviews the images against the inspection scope, and a site lead who signs off on permits and flight zones. Vendor material describes two-person teams, and a split that keeps one trained inspector on sign-off fits most refineries.

The crew that remains is smaller and aimed at different work. Instead of climbing every stack, the inspector spends time on the findings the camera flags, the contact checks the drone cannot make, and the reports that carry the sign-off. Fewer people at height is the goal, and no people in the loop is not.

Plan staffing before you change the scope. Overtime, night coverage and sick-day cover are where a small team gets stretched, and the review found no refinery figures for those, so set coverage against your own shift records.

What can a drone not do at a refinery, and where does it fail?

A drone is not a complete replacement for inspection, and treating it as one creates risk. Contact tests, internal checks and any finding that needs a sensor on the steel still need a person, and a camera image can miss a defect that a hand or an instrument would catch.

Site conditions set limits. Wind, gas plumes, heat from active flares, GPS interference near large structures and battery life all cut the number of usable flights in a day. Airspace and site flight authorization rules also apply and vary by site, so confirm them before you plan a campaign.

The rules for drone work at height are not settled in this review. No OSHA standard specific to drone inspection was found, so the safety group should check the general fall protection rules for crews at height and confirm how a drone changes the work those crews still do.

How do I start a drone stack inspection pilot at a refinery?

Start small and measure your own numbers. Pick a few stacks with good access and known findings, run the drone alongside the crew for one campaign, and compare the images, the findings and the hours your own team records. A pilot on a handful of structures will answer the drone vs stack inspector question for your site better than any vendor timing.

We are a US commercial robot integrator. We assess the site first, including stack count, heights, flare status and access, then map the work and recommend the right robot and staffing split. The lease is quoted after that free site assessment, through financing, and we deploy, integrate, train staff and service the equipment nationwide, with one number to call.

Before the quote, bring your stack list, flare schedule, airspace constraints and existing inspection records. Those four items shape the answer more than any equipment specification.