Façade and Solar Cleaning

Start with the duty to avoid height

The Work at Height Regulations 2005 put avoidance first: regulation 6(2) says work should not be carried out at height where it is reasonably practicable to do it safely otherwise. Where height cannot be avoided, regulation 7 asks employers to give collective protection, such as guardrails, priority over personal measures like harnesses. A façade or panel robot controlled from the roof or the ground can take people off the glass for routine cleans, which is the strongest reason to consider one. It does not remove height from the job altogether. Someone still rigs the robot, inspects its ropes or rails, recovers it after a fault and cleans what it misses, so plan those tasks under the same rules.

How façade robots reach tall glass

Façade robots usually hang from a building maintenance unit, a gondola or a rope-and-winch system fixed at roof level, then work down the face. A 2020 study in PLoS ONE notes that the outer walls of buildings are cleaned in highly hazardous conditions and that many accidents happen each year. Its authors tested a rope-suspended robot that sprays water at high pressure rather than scrubbing, and with settings tuned to 8 bar it reached about 75% cleaning performance in their trials. That shows the trade-off: lighter contact protects the robot's stability and the glass, but stubborn dirt may need a follow-up. Ask your façade engineer whether roof anchors, cradle tracks and glazing coatings suit a robot before approaching makers.

Why solar farms schedule robotic cleaning

Dust, pollen and bird droppings cut a panel's output, and on large arrays the losses add up. The International Energy Agency's PVPS Task 13 report on soiling, IEA-PVPS T13-21:2022, estimated that soiling cost at least 3 to 4% of global annual PV energy production in 2018. The same report lists wet and dry brushes, cleaning robots and electrodynamic cleaning among the responses open to operators, and it points to 'best time-to-clean' models that weigh the cost of a clean against the revenue being lost. For a site owner, that means letting measured soiling, not the calendar, decide when robots run. Fit a soiling sensor or compare clean and dirty reference panels so the schedule follows real data.

Questions for a façade or solar robot supplier

Begin with the module or glazing maker, because cleaning methods can affect warranties: ask which brushes, pressures and water quality they accept, and get the answer in writing. For solar sites, ask how the robot moves between rows, how it is stowed in high wind, where its water comes from and what happens to run-off. For façades, ask about wind limits, how the area below is protected from falling water or debris, and whether the robot needs permits to work over a public footpath. Every supplier should explain its recovery plan when a unit stops halfway down a building or along a row, and who goes to fetch it. Ask too for maintenance intervals and which spares are stocked locally.

Sources and further reading

• The Work at Height Regulations 2005 (SI 2005/735) — legislation.gov.uk (The National Archives).
  UK rules that put avoiding work at height first and give collective protection priority over personal measures.
• Automated technique for high-pressure water-based window cleaning and accompanying parametric study — PLoS ONE (via PubMed Central).
  Peer-reviewed tests of a rope-suspended façade robot that cleans with pressurised water spray instead of brushes.
• Soiling Losses: Impact on the Performance of Photovoltaic Power Plants (IEA-PVPS T13-21:2022), executive summary — International Energy Agency Photovoltaic Power Systems Programme (IEA PVPS).
  Estimates the energy lost to dirty solar panels worldwide and reviews cleaning options, robots included.

Common questions

Can a robot replace rope access window cleaners on a tower?

On some buildings it can take over routine cleans, provided the roof has suitable anchors or cradle tracks and the façade is fairly flat. Setbacks, fins, balconies and angled glazing still tend to need people, and rope access teams may be needed to rig the robot or rescue it after a fault.

Who needs training to run a façade or solar cleaning robot?

Anyone who sets up, operates or recovers the robot needs training from the supplier, and anyone rigging it at height needs the competence that work demands. Keep training records, and make sure more than one person on each shift knows how to stop the machine safely.