Pressure Vessel Drone Inspection Singapore — Confined-Space Internal Survey Without Man-Entry

What Is Pressure Vessel Drone Inspection?

A pressure vessel drone inspection is the internal survey of a closed process vessel — a pressure vessel, distillation column, reactor or separator — carried out by flying a collision-tolerant, cage-protected drone inside the vessel instead of sending a person in. The drone is launched through the manway once the vessel is opened and gas-freed, and it captures high-resolution visual footage, with onboard lighting and optional thermal imaging, of the internal shell, dished heads, nozzle bores, internals, welds and protective coating.

The aircraft we use for this work is a Flyability Elios-class drone: a small multirotor housed inside a protective spherical cage. That cage is the whole point. It lets the drone make contact with the shell, trays, baffles and other internals and simply roll away undamaged, so the pilot can work through a cluttered internal volume — right up to the walls and into head sections — that an open-rotor drone could never survive. The result is a systematic, repeatable record of the vessel's internal condition, captured without a single person crossing the manway.

This is a confined-space drone inspection applied to the most safety-critical class of confined space in a process plant. The vessel's internal integrity governs whether it can safely hold pressure, and getting eyes on that internal surface has traditionally been one of the most hazardous and expensive tasks in a plant turnaround.

Eliminating Confined-Space Man-Entry

The core value of a drone vessel inspection is that it removes the person from inside the confined space. A conventional internal inspection is a major undertaking: the vessel must be isolated and gas-freed, internal scaffolding is erected so inspectors can reach the shell and heads, a confined space entry permit is raised, atmosphere is monitored continuously, and a standby team stays at the manway ready to rescue. Every one of those entries carries the risk that gives confined spaces their reputation — oxygen deficiency, residual hydrocarbons or toxic gas, and the sheer difficulty of extracting an incapacitated worker through a small opening.

Flying a caged drone through the manway removes the inspector from that hazard entirely for the visual survey, and removes most of the internal scaffolding that man-entry demands. It is also dramatically faster: a pilot can cover the internal volume of a large vessel in a fraction of the time it takes to build access and walk a team over every surface. Fewer people inside, less scaffolding, less time on the critical path — the safety and schedule gains reinforce each other.

In Singapore this aligns directly with the intent of the WSH (Confined Spaces) Regulations, whose first principle is to eliminate or reduce the need for man-entry wherever it is reasonably practicable. A drone that performs the internal visual inspection without entry is exactly the kind of engineering control the regime is built to encourage. We frame this honestly: the drone eliminates the entry for the visual survey, but the opening of the vessel, atmosphere testing, gas-freeing and standby arrangements are still governed by the entry permit and remain fully in force while the drone works.

How a Pressure Vessel Drone Inspection Works

The workflow is planned around your shutdown and the permit-to-work system, so the drone survey slots cleanly into the turnaround sequence.

Because the survey is recorded, the footage becomes a permanent baseline. On the next inspection cycle the same paths can be re-flown and compared, turning a one-off snapshot into a trend that the vessel engineer can use to track deterioration over the equipment's life.

What We Look For Inside the Vessel

The internal survey targets the damage mechanisms that determine a vessel's fitness for continued service. The drone footage lets the inspector read the whole internal surface for:

• General and localised corrosion — thinning and metal loss across the shell and heads, and the concentrated attack that undermines pressure boundary integrity.
• Pitting and erosion — sharp local pitting and flow-driven erosion at nozzle bores, inlets and impingement zones.
• Coating and lining breakdown — blistering, disbondment, holidays and failed internal linings that expose bare metal to the process.
• Cracking and mechanical damage — surface-breaking cracks, weld defects, and distortion or damage to internals such as trays, baffles, demister pads and distributors.

Findings are mapped back to the vessel geometry so the mechanical-integrity engineer knows precisely where each indication sits, and can decide where any hands-on follow-up is warranted.

Vessels We Inspect

The caged drone method suits the full range of large closed process equipment found in Singapore's refineries, petrochemical plants and terminals.

Where It Fits: Turnarounds, Standards and Honest Scope

Internal vessel inspection needs the equipment offline, opened and gas-freed, so it is scheduled into a planned plant shutdown or turnaround. On a tank the internal drone survey complements external ultrasonic thickness work and floor-plate MFL; on a pressure vessel it delivers the internal visual coverage while any required thickness measurement is taken separately. It also works hand in hand with our storage tank inspection and broader industrial drone inspection services across a shutdown scope.

The inspection is assessed against recognised codes. API 510 governs the in-service inspection, rating and repair of pressure vessels; API 572 is the companion recommended practice for vessel inspection; and ASME Section V defines the visual examination methods the footage is read against. API 510 and API 572 both recognise remote visual inspection as a valid technique for the internal visual examination, which is exactly what the caged drone delivers.

We are precise about scope. The drone performs remote visual inspection (RVI) — it sees, it does not touch. It does not replace hands-on NDT such as ultrasonic thickness measurement or crack sizing where the code or the inspector requires them. What it does is give complete internal visual coverage without entry, and act as a triage: it confirms where the vessel is sound, eliminates unnecessary entries, and pinpoints the specific locations where any hands-on follow-up is genuinely needed. The formal fitness-for-service judgement always rests with the inspector or engineer assessing to API 510.

Why Choose SG Drone Inspections

We are a specialist confined-space drone inspection provider in Singapore, focused on delivering internal vessel data that mechanical-integrity teams can act on with confidence.

Frequently Asked Questions