Ventilation New-build case study
elevation, with four on the west, adding some relief to the building’s otherwise nondescript facade. The chimneys have a concrete base section to prevent noise break-in at studio level. Higher up, concrete construction gives way to more conventional cladding. It is not possible to use natural ventilation all of the
time. When it is too hot or cold outside, the system can be flipped to mechanical ventilation mode at the flick of a switch. In this mode, a conventional ducted system pushes cooled air into the studios through adjustable high-level diffusers, with the chimneys now functioning as return air ducts. Dampers at the top of each chimney return the air to the roof-mounted air-handling units for energy recovery, rather than allowing it to escape into the atmosphere. Between the mechanical and natural ventilation modes
is an intermediate mode. This has been introduced to solve a common stack ventilation problem: air cooling in the flue and dropping back into a room, caused by the flue lining being too cold. To stop the warmed air cooling on its roof-ward journey, the flues are lined and insulated on the inside. In the intermediate mode the system will run on extract only, pulling the air up the
National Air Traffic Services objected to the turbine’s location on the flight path into Heathrow
chimney to warm it. Once the flue reaches the correct temperature the system will turn off and the air’s natural buoyancy will take over. ‘We took a lot of care over the flue design and its insulation to ensure we maintain the right surface temperatures,’ says Beaven. The studios are not the only space in the 20,000 sq
m building to use outside air for cooling: the building’s offices feature a natural ventilation mode, while the eight data centres make extensive use of fresh air for cooling. The naturally ventilated studios occupy most of the building’s ground floor. In the centre of the two middle floors are the main data centres, production facilities and editing suites, while wrapped around the perimeter of these floors is office space for the broadcaster’s 1,370 staff. The upper floors contain the transmission platform for Sky’s 160 channels. A glazed atrium at the south end of the building allows access between levels, and it houses a series of meeting rooms, a cafe and breakout spaces. ‘BSkyB was clear that it wanted people on the outside of the building, and for the “dark” spaces to be used for editing suites and data processing at the centre of the floors,’ explains Beaven. The building’s initial design was adapted to enable
the first and second floor office areas to be naturally ventilated, as part of a process led by BSkyB’s non- executive chairman James Murdoch to enhance the building’s environmental credentials. The office areas on the west elevation are only eight metres deep, and are ventilated using single-side natural ventilation, which works by opening high-level windows and low-
www.cibsejournal.com
The computer image above shows the services in the plant areas on the roof. The one below shows the connection between studio services and the roof air-handling plant. Arup says that using 3D designs were essential to being able to coordinate the roof services
level louvres. At 15 metres, the offices on the eastern side are too deep to ventilate using this system. Instead, three atrium-like chimneys have been punched through the centre of the building to help draw air across the floor plates. Glazed rooflights fitted with modulating louvers allow the air to be exhausted. These louvres are acoustically lined to prevent noise from low-flying aircraft, roof-top plant and the building’s wind turbines from entering the offices. This unusual solution has the additional benefit of allowing natural light in. Like the studios, the offices are fitted with a
mechanical ventilation system, with air supplied through an underfloor displacement system. A traffic light adjacent to the window and internet alerts will let staff know when the mechanical system is off and windows can be opened manually.
> February 2011 CIBSE Journal 31
BSkyB/Arup
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72