Custom Engineering · Scenario Customization

Custom Building and Facility Cleaning Systems

Cleaning systems are a payload-and-safety design problem: what is applied, at what pressure, and how the ground beneath is kept clear.

9 of 10Method note

Overview

Define the cleaning agent, its mass, and how the delivery is controlled — this drives the whole platform requirement.
Ground exclusion is not optional; define how it is enforced, not just that it is required.
Facade cleaning needs a repeatable track along the surface, which is a flight-control question as much as a payload one.
Waste water and runoff may be regulated; establish the local requirement before committing.

Aerial cleaning is a contact or standoff process, and the distinction decides everything

Aerial cleaning of buildings and facilities divides into two fundamentally different processes. Contact cleaning uses a brush or pad carried to the surface; standoff cleaning uses a jet of water or cleaning agent delivered from a distance. They differ in the aircraft requirement, in the control precision needed, in the surface types they suit and in the risk they carry, and the choice between them is the first and most consequential design decision.

Standoff cleaning is the more common and, for most structures, the safer option: the aircraft keeps separation from the surface and delivers a jet. It requires stable flight at the working standoff, sufficient payload capacity for liquid, and a delivery system that produces the required pressure and coverage at that distance. It suits large, accessible façades, glazed surfaces and structures where contact is impractical.

Contact cleaning produces a different result on surfaces that need mechanical action, but it imposes a much higher control and safety requirement, because the aircraft is physically interacting with a structure. Where contact is genuinely required, it should be scoped with that requirement stated rather than treated as a variant of standoff work.

What determines whether it works

The first determinant is pressure and flow at the surface, not at the pump. A jet loses energy over distance, so the requirement has to be specified as what arrives at the surface at the working standoff. That converts into a pump and nozzle requirement and into a liquid capacity requirement, and those together usually set the aircraft class.

The second is stability. Cleaning is a dwell task: the aircraft holds position while a section is treated, then moves to the next. That is a hover task, and it is what a multirotor does well. Coverage rate depends on how steadily the aircraft can hold and how accurately the operator can place the jet, so stability is a productivity parameter as much as a safety one.

The third is liquid logistics. Cleaning consumes volume quickly, and the same refill-cycle arithmetic that governs agricultural application applies here — our agriculture logistics note describes it. Where water and agent must be carried to height, mass is the binding constraint and it should be computed rather than assumed.

Surfaces, agents and the run-off question

Not every surface suits aerial cleaning, and the honest assessment comes before the proposal. Glazed surfaces, metal cladding, painted concrete and many composite panels clean well. Surfaces with loose material, fragile fixings, or coatings that are already failing do not, and a jet that removes dirt may also remove the coating.

Cleaning agent selection interacts with the surface and with what happens to the run-off. Where an agent is used, what it is, what it contacts and where it goes are all part of the assessment, and in some jurisdictions the run-off is a regulated discharge rather than a spill. Establish that before specifying the process.

Testing on a representative area is the standard way to settle both questions, and it should be part of the engagement rather than an afterthought. A test patch establishes whether the surface tolerates the process, at what pressure, with what agent, and it converts an assumption into a measured result.

Safety around occupied buildings

Cleaning usually happens on occupied or adjacent-occupied buildings, which makes separation, run-off management and public communication part of the design rather than accessories. Define the exclusion zone, control where run-off goes, protect anything below that should not get wet, and brief the building occupants or manager before starting.

Wind matters more here than in almost any other aerial task, because the jet drifts and the aircraft is working close to a structure. Set a conservative wind limit, and be prepared to stop rather than to continue while drift is affecting the result or the surroundings.

Where cleaning is combined with inspection on the same visit — which is often efficient — the two should be planned as one operation with one authorisation, rather than two tasks competing for the same airspace and the same attention. Our facade inspection configuration note covers the inspection side.

Starting a cleaning engagement

The path is: identify the surface types and their condition; decide contact versus standoff; specify what must arrive at the surface at the working standoff; compute the liquid logistics and the coverage rate; test on a representative patch; then write the safety, run-off and communication procedures before starting.

Where the surfaces or the access are unusual, or where the building is occupied and sensitive, the engagement should include a site survey and a trial before any commitment to a programme.

Send your building or structure type, surface materials and condition, height and access, water and power availability at height, and occupancy constraints to our engineering team. We will assess whether the process suits your surfaces and what the configuration would require.