Pump manufacturer Grundfos’ new office development, in Germiston, has been awarded a 5 Star Green Star South Africa (SA) – Office Design v1 rating by the Green Building Council of South Africa.

The offices and associated warehouse facilities, were developed in conjunction with property investment company Growthpoint Properties. Technical services provider Aurecon acted as the environmentally sustainable design (ESD) consultant and provided civil, structural and mechanical design and execution services.

The offices had a gross floor area of 3 400 m², while the warehouse covered 6 500 m².

“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 said.

Aurecon stated that the most notable sustainable feature of the Grundfos development, including the offices and warehouse, was its ability to be independent of municipal water supply for as much as 75% of the year.

The project’s rainwater harvesting system incorporated Grundfos’ own customised plant to purify harvested rainwater to produce drinking-water quality, with the domestic water supply of the building having been designed to use three different sources of water, namely rain, borehole and municipal water.

“With an extensive rainwater catchment area, oversized attenuation tank and purification plant, the quantity of rainwater supplied to the building exceeds the demand for municipal water, except in the dry months of July and August,” Aurecon pointed out.

To address this weather-dependent shortage, the system was designed to use borehole water, with the building using municipal water only in the event of rain and borehole water being exhausted.

“With expected zero demand for municipal water supply during the period of October through to May, the design of the rainwater harvesting system – incorporating the Grundfos [water-treatment] technology to [produce] drinking quality water – considerably contributes to the alleviation of the stress in the bulk potable-water supply network,” Aurecon said. 

Further, the office’s west façade incorporated vertical shading louvres consisting of Grundfos solar panels and mesh, which would absorb the west-side sun energy, generating enough electricity to run all pumps in the rainwater purification plant.

Other Green Star requirements met by the Grundfos building included 70% of demolition and construction waste having been reused or recycled to reduce the amount sent to landfill, all paints, adhesives, sealants and carpets having been selected in terms of the Green Star guidelines for low volatile organic compounds, and thermal insulation having been 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 louvres on the western façade, electricity was also generated by wind turbines on the roof.

Fresh air provided in the building exceeded the minimum regulatory requirements of SANS 10400-O and energy consumption was optimised by using variable-speed drives for mechanical equipment, energy efficient lighting and heat pumps for supplying hot water for the kitchen and gymnasium. All energy consumers above 100 kVA were also submetered and monitored.

Further, daylight glare control was achieved through vertical fixed shading elements in the western façade, which incorporated photovoltaic panels and internal blinds in the occupied areas, facilities encouraging the use of bicycles were provided and there were dedicated parking spaces for employees with fuel-efficient vehicles.