Engineering Facility at the University of Pretoria
As part of the implementation of its environmentally friendly policy, the University of Pretoria (UP) has invested more than R400 million in the construction of an innovative, environmentally friendly, multifunctional engineering and parkade building. The University received a grant from Government as partial funding for the expansion of its Faculty of Engineering.
Mass earthworks in preparation for the construction of the building, situated behind the Aula theatre, started in May 2009.
- Total excavation: 57 600 m³ ≈ 1 280 average swimming pools
- One 6 m³ truck left site every 3,5 minutes over a contract period of 64 working days
Construction was concluded in July 2011.
- Total concrete volume: 16 800 m³ ≈ 373 average swimming pools
- Formwork: 65 000 m² ≈ 13 rugby fields
- Reinforcement: 1 570 000 kg ≈ 994 km of 16 mm rebar ≈ from Pretoria to Beaufort West
- No of bricks: 1 180 000 ≈ row of 270 km from end to end
- Painted surfaces: 67 000 m² ≈ 8 375 litres @ 8 m²/litre coverage ≈ 1 675 5-litre tins
- Glazed area: 2 242 m² ≈ half a rugby field
The seven-storey building includes four and a half levels of parking, of which two and a half are underground, providing approximately 1 000 bays, six lecture halls for some 1 800 students and two levels of laboratories and offices for postgraduate students. The entire floor area of the building is approximately 40 000 m² (eight rugby fields).
(A) Innovative design
In its brief, the University challenged the architects to come up with a design that is in line with the current international trend to make buildings as environmentally friendly as possible. The University also made it clear that the building needed to be designed in line with the principles of the Green Building Council of South Africa’s Green Star Rating System. The rating recognises and rewards environmental leadership.
Although a Green Star Rating System has not yet been formalised for a mixed-use educational building type, the design team employed best practice in all regards to register the development in future.
Ratings are based on the innovative use of design, construction and operational practices that significantly reduce or eliminate the institution’s impact on the environment and its occupants.
In addition, the design, material and technology used should lead to a reduction in energy and resource consumption and create improved human and natural environments.
ARC’s conceptual design focused on assimilating the entire brief in the most cost-effective, yet sustainably responsible way. Additional capital expenditure was only sacrificed if it could be retrieved from life-cycle costing, or proven as an environmental investment.
According to Mr De Jongh and Mr Anton Frylinck from Spoormaker and Partners – the engineering company responsible for the energy, air-conditioning and Building Management System (BMS) analysis – the new building meets all these requirements.
(B) Environmentally friendly elements to regulate temperature
-B1: Innovative design elements (Focus on the incorporation of various elements to shade the building to reduce heat induction)
- Performance glass reduces solar radiation by up to 48% in summer and stops heat from escaping in winter.
- Solar screens eliminate direct solar radiation by approximately 50%. The screens are made up of louvres and mesh screens designed in accordance with year-round sun angles for summer and winter conditions, as well as daily sun azimuth.
- Isolation material applied to the underside of the slab between the underground parking garage and the first floor of the building where the offices and lecture halls will be located in order to minimise the loss of heat to these spaces during winter months.
- Extensive use of plants to shade the building against the sun. For this purpose ARC designed special frames which house plant holders that can easily be removed and replaced. It is the first time that this system is used in South Africa.
-B2: Energy efficiency
- A naturally ventilated atrium filled with plants that will help to reduce CO2 emissions. As a result, less air-conditioning will be required to cool the building. This means that the building’s energy efficiency is measured at 25% below the requirements in terms of SANS 204.
- Spill-over air from mechanically ventilated lecture halls is also used to cool down public areas in summer and to heat these areas in winter. Attenuated louvres were provided over lecture hall doors to accommodate such.
- The floor slab of the P3 parking level has been lifted 750 mm above natural ground level in order to naturally ventilate the P2 basement parking level via openings in the slab or green retaining block walls north and south of the parkade.
- A chimney convection system, which draws warm air out from ceiling voids and relieves such at roof level, was also incorporated in the design. Apart from the energy saving, the system also allows for the inflow of fresh air which averts sick building syndrome.
- A rainwater harvesting system has also been included. A 50 000 litre tank was installed below the parking garage which allows for water to be redistributed throughout the building for irrigation as well as fire water. Due to this use, should the water level drop below a certain level, the tank will be filled with municipal water. This will cool the building down even further.
- Air-conditioning will be provided in the form of a chilled water variable air volume system, which greatly reduces energy consumption. The system makes use of a chiller to cool water down, which is then distributed throughout the building. The system automatically measures the temperatures on the inside and outside of the building. It then automatically adapts the inside temperature to a comfortable level.
- A Building Monitoring System (BMS) will be used, which automatically controls/monitors all systems in the building, including the use of electricity as well as the monitoring of water and CO2 emission levels.
- In addition, all sanitary fittings provided with economy-cycle water closets and taps will be fitted with control valves to minimise water flow periods.
- Chilled slab mechanical systems were used. Water pipes are cast in the slabs in order to be able to heat the slab or cool such based on requirements. The system is quite complex and new in South Africa, and therefore required intricate coordination between all parties. The massive saving on life-cycle costing of this system made it the preferred solution for the client.
-B3: Power saving
Power-saving techniques include the use of occupancy sensors which detect movement of nearby people or objects such as cars.
This system eliminates the need to burn lamps in areas that have not been occupied for at least 30 minutes where, depending on the location and application of the area, power saving is achieved.
These sensors are mostly employed in the parking areas, lecture halls and engineering laboratories of the new building.
Although not a recent breakthrough, T5 fluorescent lamps will also be used to add to the energy saving of the building. In the past, T8 fluorescents were used, but the newer T5s deliver the same amount of light output while using less energy.
The older T8 luminaire used analogue control gear which used approximately 10 W of power for every hour of operation or 10 to 20% of the lamp power. The newer T5s, however, use electronic control gear which only consumes 3 to 5 W of power per hour, less than half of the older control gear.
In addition, all other areas such as walkways, passages and some of the external lighting make use of compact PL lamps ranging from 9 W to 26 W, which have replaced the standard low-voltage 50W lamps
- B4: Construction material
In terms of construction material, the architects made use of environmentally friendly material such as concrete, clay bricks, glass, ceramics, organic wool isolation, gypsum boarding and Envirodeck, which is a composite decking system made from recycled plastics and timber.
(C) Security features
Access to campus and the parkade is gained via a 7-lane boomed gate with pedestrian gate-house. The parkade forms a sub-security zone on campus and therefore major security measures needed to be set in place. In order to gain access to campus from the parkade, all users have to cross access-controlled turnstiles and sluices. This becomes rather challenging as it is in direct conflict with fire escape requirements.
There is a high requirement for security to protect the vast amount of computers and electronic equipment in the laboratories and offices. Therefore the entire facility houses over 228 security cameras, further facilitated by the additional requirement for lecture halls to be used during exam periods.
The parkade is split in two, providing reserved parking for lecturers and University staff as well as open parking for students and visiting public. The open portion is controlled by a pay-on-foot parking system as used at shopping centres. This is a new system on campus and will have to work side by side with the University's existing security service provider.
As for any project this one was not without challenges. The site is more than 100 years old and therefore unpredictable in terms of an 8-metre deep excavation. The University spent about R2 million at the beginning of the project in order to locate and reroute existing services.
The project was further interrupted by heritage influences and approvals to be obtained due to the close vicinity to old buildings. A large amount of money was also spent on preserving a lane of fever trees to the south of the construction.
Doing construction on a living campus is in itself a challenge in terms of access to site, noise and dust pollution and security measures required. Nevertheless, the project progressed rather smoothly and all parties involved learned a lot working together on a very complex project.