Giants also need air
The highest requirements for smoke extraction and ventilation in multi-storey buildings.
Today, nobody would be astonished at the Tower of Babel, which is presumed to have been 90 metres tall. The tallest building in the world at 828 metres, the Burj Khalifa in Dubai, is planned to be ousted from its top spot in 2020 by the 1007 meter tall skyscraper, the Jeddah Tower, in Saudi Arabia. Even if Europe's vertical building dimensions do not match up in direct comparison, Europe still remains the market leader in SHEV and ventilation Technology.
In our driven edition “High”, you can find out about the kind of challenges being faced in the planning and implementation of SHEV and ventilation technologies in skyscrapers and at heights in general. With D+H, you receive the highest quality. This is true whether regarding planning support, maintenance of SHEV and ventilation systems at dizzying heights or high-performance window drives and control systems that make such tall architectural structures safe.
Lakhta Center – Architecture above the clouds
D+H equips the highest office tower in Europe with over 2,400 window drives for natural ventilation and delivers property-specific installation solutions.
The Lakhta Center in St. Petersburg is a true skyscraper, with the peak of the office tower literally disappearing into the clouds on certain days. Standing over 460 metres in height, the new headquarters of Russian energy company Gazprom is the tallest naturally ventilated office tower in Europe, and indeed the world. The project called for specialists to incorporate natural ventilation solutions into the building – from the planning stage all the way to execution. When it came to choosing the right window drives, high wind pressures and wind suction loads in particular had to be taken into account.
Electric window openers were to be installed in five two-storey atria with a total façade area covering approximately 100,000 m² —with the building management system directly controlling everything. Ronald Schwan, Senior Key Account Manager of the D+H Group, sat down with us to clarify the key aspects of this exceptional Project.
What requirements did our customer have for D+H?
First and foremost, an extremely ambitious schedule for such an enormous building. Our customer was Josef Gartner GmbH, renowned worldwide for their façade designs. All parties involved in the project had only a narrow window of time to make the project a reality, since the building had to be completed before the football World Cup in June 2018. Ultimately, it was effectively the highest grandstand of the World Cup—allowing a direct view into the stadium of St. Petersburg. The building was therefore of utmost priority for the investor and users, as well as for the city itself.
The architectural requirements were particularly demanding. Imagine the building as a huge needle. The diameter of the Lakhta Center is at its thickest about a quarter of the way up. It tapers down towards the base and then extends upwards to form a point at the top. To achieve this elegant design, the façade was to slant outward in the lower storeys and inward towards the upper storeys. However, it wasn't just the special shape of the façade which made this project so exciting—its sheer size was naturally going to be a special challenge too. Just to give you a sense of the dimensions we're talking about, the façade's surface area of 100,000 m² is about the size of 14 football pitches combined. Natural ventilation solutions were to be integrated into five storeys in this area. Starting from a height of over 400 metres, that's no easy task. Completely different wind pressures and wind suction loads are prevalent at these heights. The tendency here is to use more, rather than fewer, lock drives to keep the windows sealed.
What real-world technical solutions have you implemented?
Cold-formed glass which can be curved up to 40 mm was used for the dynamic design. Consequently, there are no corners or edges along the entire façade. Altogether, there were eight different main façade types, wrought with a total of 16,505 different individual elements. The top of the tower was cased with steel as well as with a stainless steel mesh and stainless steel profiles. Its elegant design thus appears as transparent as the glass façade, fitting into the aesthetic appearance of the building.
The Lakhta Center can be naturally ventilated by sashes in the façade, 1.2 m in height and 93.8 cm in width. The façade is attached to slightly curved steel beams, which span across two storeys. In terms of motors, the windows were fitted both with 1,240 D+H KA Series chain drives with a 600 mm stroke as well as with D+H VLD Series lock drives. The KA Series chain drives were surface-mounted and the VLD Series lock drives were integrated into the profile. Panelling covers the chain drives so that they are not visible from the interior. The ventilation process uses side-hung vent windows which open inward at a 45 degree angle. Why is the opening angle so large? The windows in the Lakhta Center are particularly deep and thus laterally seal each other off. This extra-wide opening angle had to be created to fulfil the required ventilation cross-section. D+H developed a rotatable bracket specifically for this building in this regard, which would even have allowed an opening angle of up to 80 degrees if necessary.
What were the greatest challenges for this project?
A long, highly detailed project run-up phase was necessary. In addition, it was of course a challenge to overcome the powerful positive and negative wind loads at these heights, both for planning the right window drives as well as during subsequent implementation. To keep the windows tightly sealed, a decision was made to go with a combination of lock drives and chain drives. By using lock drives, the loads are safely transferred via the fittings into the window frame profiles, relieving the chain drives and window hinges. The window thus remains securely closed despite the high wind pressure at this height. It was important for us to develop a solution for the customer at a reasonable cost where reliability had the highest priority.
In what ways could you offer support during the planning of the Lakhta Center?
Our customer, Gartner, had very high demands regarding our development. We generated a 3D sash and integrated our drives and drive connections into the design of the profile. Then we equipped a model sash with our technology at our customer's facility before testing it extensively for reliability and leaks.
Why was the decision made to work with D+H on this prestigious project?
Our window drives met all of the requirements stipulated in the tender document text, and our customer was aware of the quality of our products from previous projects.
And that was all the more important in this project. Imagine a service employee having to constantly replace defective window drives up there — that's no fun!
Another reason why D+H was chosen was our international service network. Somebody was needed on-site in Russia who would be able to service the window drives. We also worked together with D+H Russia to overcome the language barriers with the supervisors at Lakhta. Among other things, D+H Russia translated the Russian data sheets for us. That proved a tremendous help.
Fresh air in the skyscraper
The 5 highest D+H reference buildings
After the Tokyo Sky Tree, the Canton Tower and the CN Tower comes the Ostankino Tower in Moscow. At 540 m tall, it is the fourth-highest TV tower in the world (according to CTBUH ranking) and thus the highest D+H reference building. At number two is the Lakhta Center, the highest commercial tower in Europe. The Gazprom Tower in St. Petersburg reaches the skies at 462 metres. With just under a 100 metre difference in height, a Russian building follows closely behind—the Russian Federation Tower in Moscow. It tops out at a lofty 374 metres. An Austrian building makes fourth spot. At 250 metres, the DC Tower in Vienna reaches higher into the sky than the famous St. Stephen's Cathedral, which in comparison comes in at an architectural height of 136 metres. The Warsaw Spire in Warsaw completes our top five. It comes in at 220 metres.
Drives for the highest levels of performance
Which window drives are suitable for the greatest loads?
Various aspects should be observed when selecting suitable window drives. Alongside the customer specifications of the fire protection strategy, the cable planning and technical requirements with regard to force and stroke and the installation situation in the building also needs to be taken into account. From the viewpoint of aesthetics or functionality, how far into the room can—or may—window drives protrude? As they are, for example, exposed to moisture, which protection class do they need to fulfil? D+H offers two different main types of motorised window drives to optimally fulfil the respective building-specific requirements of specialist planners and architects: Chain drives and rack and pinion drives.
While chain drives open heavy windows and flaps using a chain with rigid backing, rack and pinion drives open and close using a robust rod. Due to their design, which features an internal chain guide, chain drives will not protrude into the room. This allows them to be easily combined with interior shading elements, for example. So, for heavy and large windows, those who value the combination of power and aesthetics will opt for CDP-TW Series chain drives. However, if moisture and chemical resistance or an extremely large chain stroke are crucial factors for you, then the DXD Series rack and pinion drive are the perfect choice. These have a higher protection class than the chain drives and are additionally available with either the “WS” option for use in swimming pools or the “W” option for installation in outdoor Areas.
Apart from their differences, the two window openers however have much in common: both bring truly high performance with a force of pressure of up to 3000 N.
- Type: Chain drive
- Application: NSHEV, SHEV, ventilation
- Force: 3000 N
- Supply: 24 V DC, 230 V AC
- Nominal current: 8 A (24 V)
- Effective power: 160 W (230 V)
- Synchronous number: 2
- Stroke: up to 1000 mm
- IP protection: IP 32
High up for the Chancellor: What to do when the window drive doesn't close?
Service story by Svend Leisering, D+H Mechatronic AG
Actions speak louder than words. There are times when a saying really hits the nail on the head, but in this case, this saying doesn´t tell the whole story. If we had not been able to close this flap quickly enough, then we wouldn't now be able to enjoy a small sandwich 25 m above Berlin's railway tracks with a view of the "Reichstag". A relaxed midday break on the roof of the new main train station, with our legs dangling towards the ground and angry dark clouds behind you, would not have been possible. May 31, 2006 started off frantically and with a challenge.
Two days before, the telephone rang. It was a distress call from the capital city. “Mr. Leisering, that one flap in the 2nd phase of construction isn't closing. The day after tomorrow is the grand opening of the train station, and Angela Merkel is going to hold her opening speech in the entrance hall. The open flap that just doesn't want to close is located directly above this area.” As the understandably concerned voice of my general contractor resonated, I took a look out the window. The rain was pouring down. I ended the call quickly. With a lot of motivation, the will to find a solution, the necessary equipment and a fast car, we headed in the direction of the Lehrter train station, which is the Berlin central station today. Approximately 2,000 special 230 V ZA Series rack and pinion drives were installed during the first construction phase, and approx. 870 DXD drives were installed during the second phase. A really exciting project. An extremely challenging project. This is because, among other reasons, apparently DXD drives don't like obeying third-party controls.
As was discovered in the course of repairing the roof, the non-freely accessible controller had triggered faults in the drive. Our DXD was therefore fully innocent. It had no way of knowing whether to be open or closed. Thus, the "Angie flap", as we affectionately dubbed it (in reference to Angela Merkel), just stayed open. Four hours and a lot of sweat later, the danger was averted. The flap was reconnected and plugged back in. It finally closed and the podium remained water-free. And the next day during her speech, the real “Angie” stayed dry as well. A few years have now passed since the opening of the Berlin central station. Twelve years during which D+H's experience and the trust placed in us has continued to grow and the building solutions by D+H have remained individualised and unique. Every bit as unique as my memory of that picnic on the 25 m rooftop of the Berlin central station, where the closed flaps continue to protect our Chancellor— and all others who walk there – from downpours.