Drone building cleaning glossary

By Vincent Goleau, founder of CleanAlta, professional drone pilot since 2014Published 31 October 2026Facts checked against sources linked in the text

Aerial work platform (boom lift, cherry picker)

A truck- or trailer-mounted basket on an articulated arm. CleanAlta uses a 40 m platform for detail work and corners the drone cannot reach. Needs ground space and a flat surface.

Algae and black mould

Biological growth on damp, shaded surfaces: green film and black spots on cladding, render, stone and roofs. Removed with a treatment pass and a rinse, not with water alone.

Biocide

A product that kills moss, algae and lichen. On roofs CleanAlta applies slow-acting biocide or enzymatic treatments chosen for the material and used according to the label. Not used on glass.

BMU (building maintenance unit, gondola, cradle)

A suspended cradle on a roof rail or davit, used to clean and maintain tower façades. Efficient where it exists and reaches every façade; blind to podiums, canopies and setbacks.

CAAT (Civil Aviation Authority of Thailand)

The Thai aviation regulator. Drone operators and pilots must be registered with the CAAT; flights in cities, near people or in controlled airspace need its permission.

Cleaning rate

Surface cleaned per hour. CleanAlta’s tethered drone works at 500 to 800 m² per hour on glass and cladding, depending on dirt, method and protocol.

Curtain wall

A non-structural outer wall of glass and aluminium hung on the building frame. The typical façade of office towers and recent condominiums, and the drone’s best surface.

Ground unit (ground station)

The equipment on the ground that feeds the tethered drone: power supply, water pump, tether reel. Housed in or next to the van.

Hot spot

A cell in a solar module that overheats because it is shaded, often by a bird dropping, while the rest of the module produces. Can damage the module permanently.

Low pressure

Spraying at a pressure that cleans without stressing glass, seals or coatings; the opposite of pressure washing. Standard for glass, solar modules and painted surfaces.

NBTC (National Broadcasting and Telecommunications Commission)

The Thai regulator that registers drones as radio equipment. Every professional drone in Thailand must be registered with the NBTC as well as with the CAAT.

Osmosed water (purified water, RO water, DI water)

Water passed through a reverse-osmosis membrane, and sometimes a de-ionising resin, so that it contains almost no minerals. It dries on glass without marks, which is why no detergent and no wiping are needed. CleanAlta heats it for better cleaning.

Perimeter

The area under the flight path closed with cones, tape and a ground operator so that nobody walks under the drone. Mandatory on every CleanAlta job.

Pilot site

In the CleanAlta Thailand program, a building that agrees to a first, documented job in exchange for a tailored offer. See the pilot program.

Rope access (abseiling, industrial climbing)

Technicians working on ropes from roof anchors. Precise on complex façades, slow on large ones, and puts people at height for days.

STS (standard scenario)

In European drone regulation (EASA), a pre-defined operational scenario with its own training and rules. CleanAlta’s French operations follow STS-01 for urban flights. Thailand has its own framework under the CAAT.

Tethered drone

A drone linked to a ground unit by a cable that carries power and, for cleaning, a water hose. It can fly for hours, cannot fly away, and is the aircraft CleanAlta uses for façades and roofs. Under 25 kg in France; 24 kg on the AP-HP hospital job.

Third-party insurance

Insurance covering damage to people and property outside the operation. Thailand requires at least 1,000,000 THB for professional drone operations.

Water-fed pole

A telescopic carbon pole with a brush and purified-water feed, operated from the ground. CleanAlta’s reaches 17 m, about five floors. The cheapest method below that height.