C-DRONE GUIDE · 26 AUGUST 2026

Drone and Metal Finishing Plant (Electroplating): ICPE Heading 2565, Roof Corrosion and Prices

On a metal finishing plant, one look at the roof is enough to date the last maintenance campaign. Hot process tanks continuously release acid mists that the extraction fans push skywards ; the air scrubbers capture most of it, but what gets through comes back down, and always in the same places : the steel deck sheets, the polypropylene ducting, the fixings, the stack collars, the top of the cladding. The result is a roof ageing two to three times faster than the warehouse next door, with a perforating rust spot appearing exactly where nobody goes to look. Here is what the drone documents on an electroplating, anodising or zinc-plating workshop — roof, ducting, scrubbers, tanks, effluent treatment unit —, what it emphatically does not replace, and the prices.

Published on 26 August 2026, reviewed on 26 August 2026 — regulations in force as of August 2026.

Electroplating, anodising, zinc plating: ICPE heading 2565 and tank volume

A workshop depositing zinc, nickel, chromium or copper by electrolysis, anodising aluminium, or phosphating and pickling steel before painting falls in France under ICPE heading 2565 : metal coating or treatment (cleaning, pickling, conversion including phosphating, polishing, chemical etching, vibratory finishing, etc.) of any surface by electrolytic or chemical means. The heading expressly excludes four neighbours : 2563, 2564 (cleaning and degreasing with organic or organohalogenated solvents), 3260 and 3670. The classification criterion is specific to the trade and worth understanding properly : it is the volume of the tanks used for treatment, meaning the sum of the capacities of each tank containing active products and taking part in the operation — including those in which parts are not immersed. Rinse tanks, whether dead or cascade, are excluded from that calculation. A workshop can therefore show an impressive total tank volume on the shop floor and a much lower classification volume.

Since decree no. 2019-292 of 9 April 2019, the authorisation regime has been removed from the heading in favour of registration. Declaration with periodic checks now covers liquid processes with a tank volume between 200 and 1,500 litres, gas-phase treatment and vibratory finishing above 200 litres ; registration covers the use of cadmium, the use of cyanides with tanks above 200 litres, and liquid processes above 1,500 litres. General requirements are set by the order of 30 June 1997 for declaration and by the order of 9 April 2019 for registration, the latter jointly covering headings 2564 and 2565. Above 30 m³ of useful tank volume excluding rinse tanks, the installation moves into heading 3260, an activity falling under the Industrial Emissions Directive (IED) and subject to authorisation : it is to these installations that the order of 30 June 2006, refocused by the order of 9 April 2019, now applies.

The trade's hard point: a roof eaten away by acid mists

Ask any technical manager at a metal finishing plant what costs them most outside the baths themselves : they will say the roof. The mechanism is well known and relentless. Hot baths — sulphuric or hydrochloric pickling, anodising, chrome plating — release aerosols that the hoods capture and the extraction fans discharge at roof level. Air scrubbers neutralise most of it, but a scrubber never reaches a hundred per cent, packing fouls up, a recirculation pump fails over a weekend, a make-up flow drifts. What escapes then falls back within a few metres of the discharge point, downwind, as fine acid droplets that attack the coating on the steel deck sheets, the zinc on fixings, verge seals, duct clamps and stack collars. A roof that would last thirty years on a logistics warehouse perforates in ten or fifteen around an extraction fan — and the perforation happens exactly where nobody sets foot, between two ducts, on a verge zone or behind a scrubber.

This is a textbook case for aerial inspection : a large surface, difficult access and a defect to be spotted visually whose extent matters as much as its presence. A study by P. Savino, F. Graglia, G. Scozza and V. Di Pietra, published in 2025 in Computer-Aided Civil and Infrastructure Engineering, combined drone photogrammetry with neural-network semantic segmentation to automatically quantify corroded surfaces on steel transmission towers : the model, trained and validated on 999 field photographs, reaches a validation accuracy of 90.8 % and lets detected corrosion be mapped onto the structure's 3D model, and therefore measured in area (see the study on Google Scholar). The logic transposes directly to a workshop roof : what the operator needs to know is not merely that there is rust, but how many square metres, where, and whether it has progressed since the previous campaign. This service falls under our drone roof inspection offer.

Extraction ducting, stacks and gas scrubbers: what an overflight documents

The extraction network of a metal finishing plant is a structure in its own right : hoods above the tanks, a network of polypropylene or PVC ducting — materials chosen to resist acids but sensitive to ultraviolet light and thermal deformation —, air scrubbing towers with their packing and recirculation sump, fans, then discharge stacks. Nearly all of it is on the roof, and nearly none of it is reachable without a lift, a fall-arrest line or rope-access technicians. A photogrammetric flight renders the whole thing as an orthophoto and a 3D model, supplemented by close manual-flight passes : ducting sagging between two supports, a loose clamp, a split flexible connector, a corroded fixing, whitish cracking of exposed polypropylene, a scrubber body streaked with runs, a handrail or service walkway rusted at its base. Stack collars and shells take the same beating as the roofing : our guide to drone inspection of industrial chimneys and silos details how to cover a vertical stack, and our guide to pipe-rack and industrial piping inspection covers the logic of a corrosion survey on an outdoor network.

On this kind of structure the benefit is not only access : it is repeatability. Repeated year after year on the same flight plan, the coverage becomes a comparable series that shows the rate of degradation and feeds a multi-year maintenance plan rather than a string of emergency repairs. Automated processing of these images is moving fast : the CorrDetector framework proposed by A. R. M. Forkan, Y.-B. Kang, P. P. Jayaraman and co-authors, published in 2022 in Expert Systems with Applications, combines several convolutional neural networks to identify the structure and then extract corroded areas from high-resolution drone images of telecommunication towers, outperforming the reference models of the time (see the study on Google Scholar). At an electroplating workshop these tools remain a reading aid : a qualified professional — roofer, structural consultant, maintenance department — decides what happens next.

Tanks, bunds and effluent treatment: what the drone sees, and what it does not replace

The wet side of the site lends itself to a useful overflight, provided one is honest about its scope. From the air, the following are documented without difficulty : the layout and clutter of outdoor bunds, standing rainwater in a bund meant to stay empty, a run or dried stain around an acid or caustic storage tank, the condition of sumps and collection channels, access to shut-off valves, the external condition of the effluent treatment unit's vessels — chromate reduction, cyanide destruction, neutralisation, filter press — and the apparent fill level of buffer basins. A periodic photogrammetric survey of the basins also shows silting and the useful volume actually available, exactly as at a wastewater treatment plant or a tannery handling chromium effluent, whose treatment chain closely resembles that of a chrome plating shop.

What the drone does not do must be stated plainly, because that is exactly where the site's compliance is decided. It performs no bund leak-tightness test : that verification requires close examination of the lining, a water-fill test or an equivalent method, usually entrusted to a third party. It takes and analyses no effluent sample : discharge parameters — hexavalent chromium, cyanides, nickel, total metals, pH, suspended solids — are measured in a laboratory on samples, at the frequencies imposed by the order applicable to the installation's regime. Nor does it contribute to regulatory stack emission monitoring, which relies on in-duct measurements by an accredited body. Finally, a drone thermographic patrol reads a surface temperature : it spots an overheating fan motor or an abnormally cold scrubber, but detects neither a bath leak nor a pollutant concentration. The drone documents the envelope and the surroundings ; the process and its compliance stay on the ground.

Mission method, coactivity and prices

The mission takes half a day at a typical workshop, a full day if the site combines several buildings, an extensive effluent treatment unit and a thermography request. It starts with a briefing with the QHSE or maintenance manager : locating the extraction fans and scrubbers in service, the prevailing wind direction and the quietest discharge window, areas where the aircraft must not hover directly above a discharge point, forklift and chemical delivery traffic, a take-off point clear of unloading bays. The flight then runs a photogrammetric pass over the roofing and buildings for the orthophoto and 3D model, close manual-flight shots of each fan unit, each scrubber, each stack shell and each suspect verge zone, a thermal pass if included, and a survey of the basins and outdoor bunds if volume measurement is requested. As with any work on an industrial site, the prevention plan and coactivity are settled before the flight, never on the day.

Two precautions frame the quote. On the airspace side, a metal finishing plant is almost always in a business park, sometimes in dense urban fabric inherited from last century's industry : the zone is checked on Géoportail before any commitment, and particular arrangements may be needed, as detailed in our guide to flying a drone in French cities. On the contractual side, require the contractor to hold up-to-date professional liability insurance, non-negotiable on a classified site. To choose between an overflight and a working-at-height intervention, our drone versus rope access comparison sets out the criteria : the drone documents and prioritises, the rope-access technician intervenes and probes.

2026 prices (excl. VAT) : €350 to €700 for a targeted inspection of a workshop roof or of a fan-and-scrubber set ; €900 to €1,800 for a full campaign combining an orthophoto and 3D model of the roofing, a corrosion survey of ducting, stacks and cladding, a thermal pass and a survey of the effluent treatment basins ; €250 to €500 per visit for annual monitoring on the same flight plan, a format that makes particular sense in this trade where the rate of degradation is the real indicator ; €300 to €600 for a standalone survey of basins and outdoor bunds. A travel charge applies beyond a 30 to 50 km radius. Request a quote stating the roof area, the number of rooftop fan units and scrubbers, and the goal (multi-year maintenance plan, insurance file or preparing an environmental inspectorate visit).

Frequently asked questions

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Put it into practice

• Drone roof inspection: rates and cities covered from €200
• Roof inspection in Béziers Occitanie
• Roof inspection in Cannes Provence-Alpes-Côte d'Azur
• Roof inspection in Bourges Centre-Val de Loire

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