structure with two buildings on top of an accessible podium . The EY building , Tower Block 1 , is located along the eastern boundary of the site comprising 7 levels totalling 21,716m 2 . The multi-tenanted building , Tower Block 2 , is located on the western boundary , comprising 14 floors totalling 15,394m 2 .
The building responds analytically and fluidly to the organic interior and exterior space planning , blurring the interface between the active and passive , public and private as well as building and landscape .
The design consists of a 7-storey building with an active atrium space , animated by transecting stair and bridge links , together with a 13 storey office tower connected by a 5 storey high link bridge which allows for future flexibility . The visibility and legibility of the building afforded by the site , is further enhanced by the two storey podium upon which it sits .
The built footprint is 98,800m 2 and the development rests on nine stories of basement parking including service areas , cold rooms , electrical plant rooms and water storage tanks . There will be a total of 1,051 staff parking bays and 100 visitors parking bays in the EY block , with an additional 527 staff and 55 visitors parking bays for Tower Block 2 .
Vehicular and pedestrian access onto the site is controlled within the boundaries of this podium , with separate vehicular entrances for the office buildings and their services off the midblock connector and Johan Street . A grand sweeping staircase off Rivonia Road creates a seamless transition for pedestrians from street level to the podium that celebrates its views over Sandton with a hard and soft landscaped extension of the open public street that can be secured after hours .
Energy Efficiency
• Natural light is filtered into the office spaces thus avoiding the need for artificial light and reducing the energy demand for lighting . External shading devices and blinds prevent the excessive heating of the office space , reducing the need for air-conditioning .
• Lighting is controlled in the open plan offices with occupancy sensors , in zones that do not exceed 100m 2 , while smaller rooms and media rooms have individual switches . All the office spaces maintain a lighting power density of 1.89 W / m 2 / 100 Lux .
• The building management system ( BMS ) monitors and controls most electronic equipment and serves as an early warning to problem areas .
• Most of the hot water supplied to the WC ’ s , pause areas and kitchens for both towers is supplied by heat pumps .
• With all these energy efficient features the building is approximately 50 % more efficient than the notional building , with a reduced energy reduction of 214.7Kwh / m 2 / year .
Water Conservation
• Rainwater is captured in a 72,000 litre tank . A further tank provides 84,000 litres . These storage tanks are located in the basements .
• Separate pipes supply rainwater to toilets and urinals for flushing , thereby decreasing the
FAÇADE The variable nature of the internal functions of the building manifest themselves as floating floor planes that create overhangs and protrusions , further enhancing the organic relationship between the façade and the horizontal flow of the spaces .
In order to create such vertical fluidity , a unitised glass façade was adopted and articulated by vertical fins rotated at 3 degree increments , that control natural light into the open office environment ; the centres of which are defined by their orientation on the façades . The façade was constructed from a unitised performance glass with a light tint in a double glazed unit .
ENVIRONMENTAL STRATEGY A 4 Star Green Star SA Office V1 Design rating was achieved in January 2014 . The environmental strategy includes :
102 Rivonia Road 235