Kärcher cleans Loreley open air theatre

As part of its cultural sponsorship programme, Kärcher was engaged in conserving the Loreley Open Air Theatre on the Loreley cliff near Sankt Goarshausen on the Rhine. Application engineers from the specialist cleaning company removed lichens, algae and emission residues that had accumulated in recent decades on the spectator stands, towers and stairs of this popular venue and were damaging the stone.
No fewer than four different Kärcher machines were deployed on this project. HDS 10/20-4 M type hot-water pressure washers were used without chemicals to remove coarse dirt from the undressed stone, which contains iron ore. These machines use water at a temperature of 95°C and at 200 bar pressure and a flow rate of 1,000 l/h. In some places the steam setting was required to remove deep-seated deposits in the pores of the stone. A Dirt Blaster, a pencil jet nozzle that rotates at 4,500 rpm, was used on tower walls and masonry. For cleaning stairs and seating terraces, operatives used a Power Nozzle, which generates an impact pressure up to 40% higher than traditional fan jet nozzles with the same working width.
In particular, stubborn efflorescence (sintering) was removed with the help of a particle blasting gun. The gun uses compressed air to apply fine-grained blast furnace slag to the stone surfaces to be cleaned. Adding water to the nozzle largely prevents dust formation.
Iron railings and window grilles were given a gentle cleaning with an IB 7/40 dry ice blasting machine, which removes rust and surface dirt without changing the patina and the original character of the metal surfaces.
An MC 50 municipal sweeper was used to sweep in front of the main entrance and also to maintain the green areas behind the open-air seating. Quickly interchangeable attachment kits enable it to fulfil both purposes. This machine can also be used for winter road clearance services.
Building works on the Loreley Open Air Theatre began in 1932 and the theatre was officially opened seven years later with a performance of the play Wilhelm Tell. Initially, the theatre was mainly used for performances of classical plays. Since 1976, well-known international rock and pop stars have given concerts on the open-air stage. The theatre also stages festivals and opera performances. It is very close to the Loreley Rock in the Upper Middle Rhine Valley UNESCO World Heritage Site.