Technical and legal framework
This service sits within a framework of statutory duties, technical rulebooks and operational practice. The distinction matters because it determines who is responsible for what.
- Glass burn is irreversible
- Rainwater that runs over concrete, cement or sand-lime brick surfaces and then drips down glass leaves mineral deposits. As long as they lie on the surface, they can be removed. After prolonged exposure they react with the glass surface and become part of it; this condition is commonly called glass burn. After that no cleaning helps any more, only glass refurbishment or replacement of the pane. Regular cleaning is the only effective prevention and is therefore protection of the fabric, not a cosmetic item.
- Frame, rebate cavity and seal
- If only the glass surface is cleaned, acidic dirt collects in the rebate cavity over years. The seal becomes brittle, water penetrates, and oxidation sets in on aluminium frames. The damage arises invisibly and is only noticed once it has occurred. Whether the frame is cleaned as well is therefore not a question of specification but a question of maintenance.
- Coated glass and films
- Modern glazing carries functional coatings – solar control, thermal insulation, self-cleaning layers. They are sensitive to abrasive cleaning equipment and to strong alkaline or acidic cleaners. Because the glass surface does not reveal this, manufacturer specifications for the glazing take precedence over any industry rule; their effect arises through the purchase contract, not as a statute. Professional review of the manufacturer's specifications in their full text is required. Removing films and lettering is a separate category of work and belongs in the schedule of services as an item in its own right.
- Work at height
- Work at height is governed by a different set of rules than any other cleaning service. The Operational Safety Ordinance requires a risk assessment and the selection of suitable equipment; it is a statutory requirement. The associated Technical Rule TRBS 2121 fleshes out these requirements – it is not a rule of law in the strict sense, but it does carry a presumption effect. For member businesses of the Berufsgenossenschaft (the German statutory accident insurer for the trade sector), DGUV Vorschrift 1 is binding. Professional review of the Technical Rule in its full text is required. In practice it is access, not reach, that must determine the choice of method.
- Road space below the work area
- If a piece of equipment stands in the public road space, a liability situation arises from the duty of care towards persons on the premises under the German Civil Code – dripping water, falling tools, closed-off routes. Depending on the surface, road traffic requirements are added, such as a no-stopping zone or a special-use permit. Standing areas and traffic safety are therefore planning elements in which the client has a say.
The rulebooks named here describe requirements for how the work is carried out – they are not a certification held by BREREI. VDI and DIN normative texts are chargeable and were not available in full; where a statement touches the normative detail, this is noted in place.