The office component of an office and warehouse facility was awarded a Five Star Green Star SA – Office Design v1 rating by the Green Building Council of South Africa (GBCSA). Aurecon was commissioned as principal agent for this project in January 2012 by pump manufacturer Grundfos and listed property company Growthpoint. The offices have a gross floor area of 3,400 m², while the warehouse covers 6,500 m² and has been designed to complement the office building.
The project has been built on a high visibility site at the junction of the N12 and R24 in Meadowbrook, Germiston, giving it exposure to major routes around OR Tambo International Airport. Two major challenges were encountered on the project; those of a very sloped site with large amounts of storm water flow during rainstorms, and the need to implement environmentally sustainable design (ESD).
In developing the design, the steep cross fall on the site – a 9 metre fall across 200 m – coupled with storm water flooding from the site posing a concern, had to be closely considered. Very stringent requirements in terms of storm water management were imposed by the local authority (Ekurhuleni Metropolitan Municipality) as well as the various roads authorities (Gautrans & South African National Roads Agency Limited) to prevent flooding of the two major motorways at this junction. This required the attenuation of 1 250 m³ of storm water.
In a novel design decision, the slope of the site was used to accommodate parking underneath the buildings, resulting in the need for minimal ground works from a fill perspective, overall better space utilisation and faster construction time. In addition, a storm water attenuation facility for the warehouse and the office building was provided through an oversized (1,500 m³) concrete attenuation tank under one of the parking areas.
The project’s rainwater harvesting system incorporates Grundfos’ own customised plant for purifying harvested rainwater to drinking water quality. This is believed to be the first implementation in a commercial office and warehouse building in South Africa. The domestic water supply of the building is designed to utilise three different sources of water, namely rain, borehole and municipal water.
“The Grundfos offices were intended to achieve a Green Star SA Office v1 rating, but we applied ‘green’ principles to the warehouse as well,” Aurecon project manager, Stoffel Mentz, says.
The most notable sustainable feature of the Grundfos development, including both office building and warehouse, is the ability to be independent of municipal water supply for as much as 75% of the year. Apart from this, the office building has been designed to incorporate various sustainable features in line with Green Star SA requirements for certification. Significant ones include:
- 70% of demolition and construction waste was reused or recycled to minimise the amount sent to landfill.
- All paints, adhesives, sealants and carpets were selected in terms of the Green Star SA guidelines for low volatile organic compounds. Thermal insulation was used on the roof, the exposed ground floor concrete slab, and the spandrel panels in the façade.
- In addition to the electricity from the solar panels installed in the fixed external shading louvers on the western façade, electricity is also generated by wind turbines on the roof.
- Employee comfort and wellbeing is considered with fresh air provided at rates exceeding the minimum regulatory requirements of SANS10400-O.
- Energy consumption is optimised throughout the building by using variable speed drives for mechanical equipment, energy efficient lighting, and heat pumps for supplying hot water for the kitchen and gymnasium, while all energy consumers above 100 kVA are sub-metered and monitored.
- Daylight glare control is achieved through vertical fixed shading elements in the western façade incorporating photovoltaic panels and internal blinds in the occupied areas.
- Facilities are provided that encourage the use of bicycles.
- In a novel touch that reminds car drivers to consider sustainability, those with fuel efficient vehicles have dedicated parking spaces.
Currently there are 54 Green Star SA certifications.