C-DRONE GUIDE · 26 AUGUST 2026
Drone and Spirit Ageing Warehouses (Cognac, Armagnac): ICPE Heading 2255, Roof and Prices
In Cognac, Segonzac or the Bas-Armagnac, an ageing warehouse can be spotted from a distance by its blackened walls : this is not pollution, but a microscopic fungus that grows nowhere except near stored spirit. Behind those walls sit thousands of oak barrels racked over several levels, air permanently carrying alcohol vapour, and a fire load few other agricultural buildings reach : a warehouse fire burns fast and hot, and even the extinguishing water has to be contained so it does not pollute the ground. The cellar master or the HSE manager of a trading house has usually not set foot on the roof in years : that is exactly what a drone survey documents, without ever adding an ignition source to a building already classified as high-risk. Here is what it inspects, what the famous "black fungus" does and does not tell you, and 2026 prices.
Published on 26 August 2026, reviewed on 29 August 2026 — regulations in force as of August 2026.
The ageing warehouse, a classified agricultural building: ICPE heading 2255
A warehouse where spirits or liqueurs age — cognac, armagnac, calvados, French whisky — falls, once the volume stored crosses a first threshold, under heading 2255 of France's nomenclature of classified installations for environmental protection (ICPE) : storage of agricultural spirits of more than 40% alcohol by volume. Depending on the volume stored, the regime ranges from simple declaration to registration, or even authorisation for the largest trading-house sites — the transposition of the Seveso 3 directive in fact confirmed that a dedicated heading for these spirits was kept, rather than folding them straight into the general nomenclature for flammable liquids. A concrete, verifiable benchmark : the order of 25 May 2012, which governs the neighbouring heading 2250 (distillation), allows a distillery cellar to also serve for ageing while staying under simple declaration, provided its capacity does not exceed 200 m³ over a floor area of 300 m² : beyond that, the site moves into a different category.
This classification is not just red tape : it reflects a real hazard. Thousands of oak barrels stacked over several levels, continuous ethanol evaporation — the famous "angels' share" — loading the ambient air, and a stock whose value can represent several years of a house's output : a full warehouse's fire load far exceeds that of an ordinary agricultural building, and a fire spreads fast once it starts. That is why the prescriptions attached to the heading require, depending on site size, compartmentation between buildings, containment of firefighting water so it does not reach the natural environment laden with alcohol, and smoke-venting requirements scaled to the volumes stored.
The "black fungus" of ageing cellars: what to know before reading a roof
Around Cognac, at Segonzac, Jarnac or in the Bas-Armagnac, the walls, tiles and even the nearby trees of an ageing warehouse gradually become coated in a velvety black film, sometimes several millimetres thick. This blackening, observed and documented in the region since the late 19th century, is neither pollution nor soot : it is a microscopic fungus, now classified in the genus Baudoinia, which specifically feeds on ethanol evaporated from the barrels and colonises almost no other surface. A landmark study by John O. Ewaze, Richard C. Summerbell and James A. Scott, published in 2007 in Mycological Research, characterised the fungus's physiology for the first time and confirmed its unique ability to use atmospheric ethanol as a carbon source — an adaptation that explains why it grows only near ageing warehouses and industrial bakeries (see the study on Google Scholar).
For an inspection flight, this patina changes how the images must be read : a uniform black crust on an old roof is not, in itself, a defect to flag — it is a normal marker of the site's activity, covering sound and degraded tiles alike. The remote pilot's job is to pick out, beneath this dark film common to the whole roofline, the anomalies that are genuinely localised : a shifted or broken tile, an open ridge, a spot that behaves differently from the surrounding patina under thermography. Without that distinction, an operator or an insurer could mistake the generalised blackening for a roofing emergency, or conversely miss a crack hidden under the same layer.
Roof, lightning protection, compartmentation: what an overflight documents
Old ageing warehouses carry century-old timber roof trusses under canal-tile or slate covering, rarely designed for a heavy snow load and never meant to receive an inspector on foot : nobody climbs up there, for lack of safe access, while wear and tear keeps progressing. The drone photographs every slope in high resolution : cracked or shifted tiles, open ridges, the stubs of natural ventilation stacks — the high openings that regulate humidity and evaporation inside the warehouse — and the condition of lightning conductors, whose periodic visual check is explicitly required under the ICPE prescriptions for fire-risk sites. A full vertical orthophoto then produces a georeferenced roof plan that supports a works quotation or an insurance file.
Seen from above, the site's roofline also reveals what is invisible from the yard : the continuity — or the gaps — in the firewalls that compartment the warehouses from each other to limit a fire spreading from one building to the next, the condition of the firefighting-water retention basin where the site has one, and whether fire-service access routes around the buildings are actually kept clear. A complementary thermal pass, flown at night or early morning, also reveals roof heat loss and stray air leaks that affect the stability sought for optimal ageing — an issue close to the one we detail for a wine-making cellar, a neighbouring but differently classified building.
Private property, rural setting, classified building: the flight framework
A warehouse most often sits on private property, in a rural setting or on the edge of a wine-growing village : authorisation from the operator or owner precedes any mission, and a prior check of the zones on Géoportail helps anticipate any nearby constraint (an agricultural airfield, a listed monument, a nature reserve). The flight generally falls under the open category, sub-category A1 or A2 depending on how close warehouse staff are during the mission, with no rule fundamentally different from an ordinary agricultural roof inspection.
One nuance is worth making : unlike a sealed hydrocarbon tank, an ageing warehouse is an open building, permanently ventilated by design — that is precisely what allows the controlled evaporation sought for maturing the spirit. Its atmosphere is therefore rarely classified as an ATEX zone in the regulatory sense, unlike confined storage of a flammable liquid ; this changes nothing, however, about the building's fire load should a fire start, nor the need to keep any ignition source away from the ventilation openings during the mission. Up-to-date professional liability insurance remains, as for any sensitive site, a non-negotiable prerequisite for the contractor.
Mission method and prices
The mission is organised with the cellar master or the HSE manager of the trading house : listing the buildings to cover, locating fire-service access routes and any existing retention basins, and picking a slot that avoids barrel-handling operations. The flight runs a high-resolution photogrammetric pass over each roof — supplemented by a thermal pass where a heat-loss or leak diagnosis is requested — and concludes with a report locating each genuine anomaly on a plan, distinct from the generalised fungal blackening. This kind of survey also serves as a starting point for a technical audit before acquisition, common in a sector where buy-outs of warehouses and trading-house brands remain active.
2026 prices (excl. VAT) : €300 to €600 for the photographic inspection of a single warehouse (roof, lightning protection, surroundings) ; €500 to €950 with a complementary thermal pass ; from €150 per additional building for a site grouping several adjoining warehouses. A travel charge applies beyond a 30 to 50 km radius. This service falls under our drone thermography offer ; request a quote stating the number of buildings, their approximate roof area and whether a firefighting-water retention system is already in place.
Frequently asked questions
Does the drone create an ignition risk inside a warehouse laden with alcohol vapour?
No : the survey is flown from outside, over and around the building, never inside the confined volume where ethanol-laden air circulates. The drone therefore does not replace a certified ATEX instrument for any indoor check that may be required ; it documents the building envelope without introducing any extra ignition source.
Should blackened walls and roofs be treated as a defect?
Generally not. This dark film, caused by the Baudoinia fungus feeding on ethanol evaporated from the barrels, is a normal, expected consequence of the warehouse's activity : it covers sound and degraded surfaces alike. The mission report explicitly distinguishes it from localised anomalies (a cracked tile, an open ridge) rather than flagging it as a defect in its own right.
How does this differ from inspecting an ordinary wine-making cellar?
A wine-making cellar, where wine is produced and stored before bottling, does not fall under ICPE heading 2255 : its main concern is thermal stability for preservation, covered in our guide to thermographic diagnosis of a wine cellar. A spirit ageing warehouse adds a regulatory dimension and a fire risk specific to storing alcohol above 40% by volume, which shifts the inspection's priorities.