C-DRONE GUIDE · 7 SEPTEMBER 2026

Drones at a brick and tile works: tunnel kiln, dryers, chimney and clay quarry

A brick and tile works is a heavy, immovable site. The plant was built where the clay was: France's building-materials technical centre notes that the raw material comes from quarries "generally close to the manufacturing sites", and many French works still dig their deposit a few hundred metres from the preparation hall. In between sits a tunnel kiln 50 to 210 metres long, firing at 850 to 1,200°C and never stopping, dryers fed by heat recovered from the kiln's cooling zone, a chimney, and hectares of roofing over the production and storage halls. Almost nobody goes up there, because there is no shutdown window and the structure is hot, dusty and sometimes made of pre-1997 asbestos cement. Here is what a drone campaign documents on this kind of site — kiln casing, ducting, chimney, roofs, clay deposit — what it emphatically does not replace, and the prices.

Published on 7 September 2026, reviewed on 11 September 2026 — regulations in force as of September 2026.

Two ICPE regimes on one site: manufacturing on one side, the clay quarry on the other

Manufacturing clay products falls under ICPE heading 2523, worded in the French nomenclature as "ceramics and refractories (manufacture of products)": the installation requires authorisation as soon as production capacity exceeds 20 tonnes per day, with a 2 km public-notice radius. Above a second threshold, the plant moves into the IED regime under heading 3350, "manufacture of ceramic products by firing, in particular roofing tiles, bricks, refractory bricks, tiles, stoneware or porcelain", covering installations with a production capacity above 75 t/day and/or a kiln of more than 4 m³ with a setting density above 300 kg/m³. That heading was created by decree n° 2013-375 of 2 May 2013 and amended by decree n° 2014-996 of 2 September 2014. An industrial tile works equipped with a tunnel kiln is far above those thresholds, so it sits squarely under classified-installation inspection with all the monitoring duties that follow.

The adjacent clay quarry, by contrast, is a separate installation with its own order and its own regime: it falls under heading 2510, "quarry operation", and under the requirements of the order of 22 September 1994 on quarry operations. That text creates the obligation most directly relevant to drones: its article 15 requires that a plan be drawn up for every open-pit quarry "at a scale suited" to its area, showing the boundaries of the authorised perimeter, the excavation edges, the contour lines, the restored zones and the structures — and states that the plan must be updated at least once a year. Many operators of captive deposits, extracting only to feed their own plant, discover that requirement during an inspection visit.

The sector remains concentrated in a small number of heavy sites. The French tile and brick federation counts 134 production lines and 4,183 employees, and notes that 93% of the tiles and bricks used in France are made in France. At that scale each plant carries a substantial property portfolio — halls, dryers, covered stores, outdoor yards — whose condition drives both property insurance and ICPE compliance, and which the drone documents on the same logic described for drone inspection of an industrial glassworks: a dated visual record between two technical shutdowns, never a substitute for a measurement obligation.

What the drone actually looks at: roofs, chimney, dryers, silos and the pallet yard

The first surface, by a wide margin, is the roof. A tile works lines up a clay-preparation hall, a forming hall, a bank of dryers, the kiln hall, then a covered finished-goods store: several hectares in one stretch, often built in stages over fifty years and therefore very uneven. What we look for is concrete: broken or displaced sheets, loosened fixings, rooflights gone opaque and brittle, upstand flashings at kerb level, and above all blocked gutters and downpipes — on this kind of site, clay dust and preparation fines settle continuously, compact with the rain and clog the drainage. Spotting that before the rainy season avoids the classic sequence: water ponding above a forming line, then a leak onto an electrical cabinet. The campaign works on the same principle as for logistics and retail building roofs, with added heat and dust.

Many of these older roofs are asbestos cement. Asbestos has been banned in France since 1 January 1997 under decree n° 96-1133 of 24 December 1996: any corrugated sheet laid before that date is presumed to contain it until proven otherwise. The drone does not say whether a sheet contains asbestos — that takes a sample and a laboratory analysis — but it maps precisely where the asbestos cement is, how degraded it is and how much of it there is, which directly helps scope a future pre-works survey and price a removal package. That division of roles is set out in our guide to asbestos roofing and drones.

The rest of the list is covered in the same flight. The chimney and its stack: facing condition, anchorages, cage-ladder fixings, condensate staining, aviation marking where present — a close-up examination that avoids hiring a platform or rope access just to establish the facts, as detailed in the guide to industrial chimney and silo inspection by drone. The heat-recovery ducting linking the kiln's cooling zone to the dryers, often long, lagged and run outdoors. The roof-mounted fans and extractors, whose casings and supports age badly in a loaded atmosphere. The silos and hoppers of the clay-preparation line, the clay cellar and its conveyors. The cladding and walkways. And finally the outdoor finished-goods yard, those thousands of shrink-wrapped pallets for which the drone provides both a zone-by-zone inventory and the real ground footprint — useful data in logistics and in insurance alike, where the value exposed outdoors is rarely up to date.

Kiln and duct thermography, deposit volumes: what it delivers, and what it does not

Energy is the heart of the business. France's building-materials technical centre reports that natural gas accounts for around 96% of the clay-products sector's total energy consumption, and the process explains why: firing takes place between 850 and 1,200°C, a cycle lasts 12 to 48 hours in a tunnel kiln 50 to 210 metres long and 1 to 10 metres wide, and the preceding drying stage, running from 6 to 78 hours depending on the product, is largely fed by hot air recovered from the kiln's cooling zone. Anything that leaks in between — an insulation defect in the kiln casing, torn lagging on a recovery duct, a dryer door that no longer seals — is paid for twice: in burnt gas and in uneven firing. A team led by Renato Oba published in 2014, in the journal Applied Thermal Engineering, a full thermal analysis of a roof-tile tunnel kiln built on a three-dimensional finite-volume numerical model, accounting for radiation between kiln walls and load surfaces and relating specific consumption to the kilogram of fired product (see the study on Google Scholar). That is exactly the kind of balance an outer-skin thermal map feeds with field data, along the lines described in our guide to industrial rotary-kiln drone thermography, transposed here to a long fixed structure instead of a rotating shell.

And here is the limit, stated plainly. A radiometric thermal mosaic spots a hot spot, an abnormal gradient, a degraded insulation band along a stretch of kiln or duct. It does not size the refractory repair and does not measure remaining thickness: converting a skin temperature into residual thickness requires a thermal model calibrated on operating data, and the relining decision remains that of the refractory supplier and the kiln engineering firm, backed by contact non-destructive testing. Nor does the drone replace stack emissions measurement, which rests on the operator's instrumentation and on periodic checks by an accredited body under the conditions set by the prefectural order; it measures no concentration. And it does not replace the pre-works asbestos survey required by articles R.4412-97 onwards of the French labour code, introduced by decree n° 2017-899 of 9 May 2017, whose method for existing buildings is set by the order of 16 July 2019 and standard NF X 46-020: it only helps prepare it, by delimiting the surfaces and documenting their condition.

On the quarry side, photogrammetry answers three distinct needs: deposit volume and the year's extraction progress, the volume of clay stocks weathering in the open — a living stockpile that settles, takes up water and gets drawn down by the loader — and the annual plan update required by article 15. A team led by M. H. Rohizan published in 2021, in IOP Conference Series: Earth and Environmental Science, a direct comparison between conventional stockpile measurement and drone photogrammetry in a quarry: the gap between the two methods came to 2.5%, the authors concluding that the technique is reliable for operator monitoring (see the study on Google Scholar). The method and ground-control framework are detailed in our guide to quarry 3D modelling by drone for the annual production declaration. And then there is the ground reality, which also has to be said: you fly over a hot, very dusty site with loaders, forklifts and trucks moving constantly between the quarry, the clay cellar and the pallet yard — which calls for a serious prevention plan, flight windows timed around operations, and sensor cleaning between sorties.

Who commissions this kind of mission, method and 2026 prices

These campaigns are commissioned by the maintenance and HSE departments of clay-product manufacturers, by site management preparing a technical shutdown or a major-maintenance budget, by the operators of the adjacent clay quarry for their annual plan and extraction monitoring, by inspection bodies needing a visual baseline before a structural assessment, and by insurers or their loss adjusters to put figures on the condition of an extensive building stock. The most common trigger is seasonal: a late-summer pass over the roofs and drainage, before the rains.

The method is settled. Airspace analysis and remote reconnaissance first — a tile works is often isolated in open country, which simplifies the flight framework, though the chimney and the quarry relief impose their own margins. Then the site visit and prevention plan, with flight windows timed around vehicle movements. Then the campaign itself: a vertical photogrammetric pass for the site orthophoto and the model of the deposit and stockpiles, plus close oblique passes, visual and thermal, over the chimney, the kiln casing, the recovery ducting and the dryers. The deliverable combines a georeferenced orthophoto, a radiometric thermal mosaic of the hot structures, a schedule of defects ranked and located on plan, and, where the brief includes it, deposit and stockpile volumes with their method note. Allow half a day to a full day of flying for a typical site, and one to two weeks to report delivery.

Ranges observed in France in 2026, excl. VAT:

These amounts cover the flight, the processing and the report. They exclude structural assessment, refractory expertise, the pre-works asbestos survey and statutory emissions measurement — four services the drone prepares but does not replace. The drone thermal imaging page details the thermal side, the drone roof inspection page the roofing side. For a tile works, a brickworks or the operator of a captive deposit, request a quote stating the roof area, the kiln length, whether asbestos cement is present, and whether the adjacent quarry should be included in the campaign.

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