Oslo has approx. 565 000 inhabitants and is the political, economic and cultural centre of Norway. The town lies at the inner most part of one of the prettiest fjords, surrounded by over 300 islands and wooded mountain ranges. And the new “advertisement” on the harbour: the gigantic opera house with over 1,000 rooms inside will change Oslo’s skyline forever. It forms the transition between the town centre and the open fjord. Both from the air, from the water and from two of the most important gateways – the main station and the European road route – one’s attention is immediately drawn to the magnificent white building, which covers a total surface area of approx. 38 500 m². At a length of 207 m and a width of 110 m the building with its curved roof shape resembles a floating iceberg.
Marble on the roof
From early in the morning until late into the night: there is always something going on in the Opera House. Concerts, musicals, opera and ballet performances in the evening, guided sightseeing tours during the day, cafés, restaurants and bars all mean a lot of comings and goings by the general public. The building goes down well with the local population and with the visitors from the whole world. The largest Norwegian cultural project of the post-war period represents a huge achievement – a true masterpiece. The architectural highlight is the roof, which can virtually be walked upon completely in order to make it possible to have a view into the town on the one side and over the fjord on the other side. And the people in Oslo are making good use of it. Crowds of people fill the lavish roof construction daily.
Wherever you look: marble dominates the whole building. The complete façade and the roof consist of 90% white Italian Carrara marble. Here a total of approx. 36 000 marble panels have been used. At ground level marble has also been laid in the entrance area. Whilst the façade panels and roof panels were sealed, the covering on the floor was grouted with sand, which must not be allowed to be flushed out during cleaning. The demands made of the cleaning technology are correspondingly great. Not every machine can be used here.
There’s a lot of building going on in Oslo. Added to this there is industrial dirt. Depending upon the weather situation the share of dust and dirt in the air is very high. This settles on the sensitive marble surfaces. Even before the magnificent opening, deposits could be detected. These have to be removed professionally on a regular basis. “All visitors from at home and abroad should find attractive, appealing and well maintained grounds and buildings,” explains Erik Johannessen from the service providers responsible Statsbygg. Our requirements with regard to cleanliness are high.” Day in, day out, for example, employees are responsible for keeping the interior as well as exterior areas clean and – amongst other things – are responsible for removing acute dirt immediately.
Professional Machine Technology
In order to guarantee the white colour of the sensitive marble in the long term, since June a Citymaster 1200 CityCleaner cleaning machine is being used. This is a new development from Hako-Werke GmbH, Bad Oldesloe and is used on the roof area, which can be walked on and around the grounds of the Opera House. At its core is the attachment scrubbing deck. In combination with water, by means of rotating brushes, it ensures that town centres, multi-storey car parks, underground car parks or market places appear sparkling clean once again. In addition the machine in Oslo is equipped with a simple to operate multi-function package. With the corresponding front-mounted attachment the machine can be used all year round for sweeping and in winter for snow clearance. Sweeping unit, snow plough and snow blower as well as a device for gritting are part of the equipment. Furthermore a hand-held suction hose ensures that if required, dirt, leaves or grit can be removed without problem from every niche and corner.
With a working width of 1 330 mm the articulated cleaning machine is in its element both on large areas as well as in narrow, restricted spaces. The three universally mounted brushes adapt to every kind of surface; the highest possible degree of cleanliness is achieved. A variable pressure adjustment, which can be controlled from the cab, as well as the possibility of adding cleaning agents (option) don’t give stubborn dirt, such as e.g. soot and tyre marks or even traces of oil a chance. As a result of this combination, floor coverings can be completely revamped. They shine in a new light. This machine has proven itself in Oslo from the very first day.
The cleaning machine is in use three days a well for approx. two and a half hours each day. In a window from 07.00 until 09.30 hours the areas have to be cleaned thoroughly. The roof area amounts to approx. 20 000 m², of which 10 000 m² is covered by the cleaning machine. “The composition of the floor of this application is not very easy“, Erik Johannessen asks us to consider. The marble is not smooth but instead – following the architectural requirements – it is roughly cut and is of varying thickness. Unevenness, gaps, ridges, faults and shading dominate. Coupled with this the cleaning machine has to negotiate a whole host of obstacles as well as having to master many narrow places, so that, in general, high demands are made of the manoeuvrability and the good all round visibility.
The application conditions are also extremely difficult. The roof areas, which run into one another, have a gradient of approx. 15°. The cleaning machine must not start to slip under any circumstances. This also applies in Winter when gritting or when using the machine as a sweeper, when the dirt hopper has been filled. Furthermore, the roof construction and the sensitive marble place high demands on the ground pressure loading. Thus the machine must not be too heavy in its working state so that the surface is not damaged, causing expensive repairs.
“However, the biggest challenge was the fact that we were not allowed to use any cleaning chemicals, which would destroy the special surface coating of the marble”, recounts Erik Johannessen. It is, in fact, the case that the dirt doesn’t penetrate through the seal, despite this the dirt has to be collected regularly from the surface. “Thanks to the combination brushes, which have been specially developed to meet the application requirements, we achieve a very good cleaning result on-site whilst at the same time protecting the marble.” On the open-pore surface so-called mixed bristles have proven themselves. This is a mixture of soft and abrasive bristles, which ensures that the dirt is removed as required both deep down and from the surface. Furthermore at regular intervals the marble is resealed by a specialist company. Both measures mean that its surface is protected and the valuable material does not lose its bright, radiant colour in the long term.
In the entrance area of the Opera House the marble has been laid like normal tiles: i.e. sand has been used to grout between the tiles, which must not be washed out or vacuumed up respectively during cleaning. Here, on the one hand, the experience of the machine operator plays a big role. On the other hand, as a result of the hydraulic suction mouth lift, which can be operated from the driver’s seat, the machine allows for extremely precise work. “And the special wheels ensure that no rubber marks can result, which would leave ugly black stripes on the marble”, Erik Johannesen is satisfied to conclude.
Not only are the high quality marble areas cleaned regularly with the cleaning machine with scrubbing attachment. The cleaning machine is also used on the asphalt paths from the nearby main station up to the Opera House, in order to ensure a correspondingly clean optical impression. “We are very satisfied with the technology”, assesses Erik Johannessen. “It is simple to operate, comfortable and our drivers feel safe at all times on the roof.” With an area performance of approx. 3 750 m² per hour its economy is also the focus. All work can be finished in the given time frame.
Satisfied from the beginning
Every individual one of the approx. 36 000 marble blocks was developed on a computer and was cut to size in Italy according to specifications. Despite the relatively high air pollution in the long term they should not lose their colour. “We took the problem on board”, Geir Sabel Olsen from the Hako subsidiary in Norway looks back. “Not only the intense contact with the architect’s office, in order to clarify the structural details, but also with the marble supplier in Italy as well as the company for the special coating, resulted in the fact that we could offer a cleaning machine, which was 100% suited to the requirements on-site, able to withstand the tremendous challenge and able to ensure clean results.”
Already during the first demonstration proof was supplied that the machine technology could combat the discolouration effectively in the long term. The decision in favour of this cleaning machine was made quickly. “During the lead time we then also made a loan machine available”, explains Geir Sabel Olsen “The cooperation worked well from the very first moment“, Erik Johannessen confirms in conclusion. “We are very satisfied with the cleaning results.”