Treading lightly

by Darren

The financial services giant Alexander Forbes reiterated its commitment to green practices after its new headquarters in Sandton recently received a 4-Star Green Star office design v1 rating from the Green Building Council of South Africa (GBCSA).

Regarded as a milestone in South African green building technology and design, the financial services giant Alexander Forbes’ new headquarters in Sandton recently received a 4-Star Green Star office design v1 rating from the Green Building Council of South Africa (GBCSA).

Project specs
The new eight-storey 36 950m² building, situated at 115 West Street in the Sandton central business district (CBD), cost R840-million to build and has the capacity to host 2 500 of the group’s employees. Zenprop Property Holdings developed and owns the building, while Paragon Architects was responsible for the design. The construction, which was carried out by a WBHO-Tiber joint venture, took 22 months to complete and boasts 43 000m3 of “green concrete”.

Responsible business
“Since using energy, space and materials efficiently and limiting carbon and other environmental footprints are major concerns of any responsible modern business, especially one with a clear mandate to improve people’s lives, the environmental care and foresight dedicated to the construction of this building was a key element in our selection of 115 West Street as our new corporate headquarters,” says Edward Kieswetter, Group Chief Executive at Alexander Forbes.

Speaking at the inauguration, Kieswetter noted that there were a couple of aspects that made the building unique – the first being the design. He added that the building features a number of green elements. It is energy- and resource-efficient and environmentally responsible, as it incorporates design, construction and operational practices that significantly reduce or eliminate the negative impact of development on the environment and the building’s users.

Key design elements
Anthony Orelowitz, the director of Paragon Architects who led the project, described the major design considerations of the project. These included the built response to a slightly complicated northwest orientation, the efficiency of the floor plans, the variation of facade treatments according to orientation, and the large attention paid to glazing and light control through scallops and atria.

The complex architecture has been described as technically unique, incorporating elements such as double-storey raking columns and curved scallop walls. Paul Carew from PJ Carew Consulting described the building as “skinny”.  He noted that the building has two atria – one is introverted, while the other is extroverted.

Green elements
Specific green building measures include reducing heat loads, maximising natural light and promoting the circulation of fresh air. Other elements include energy-efficient air-conditioning and lighting and environmentally-friendly, non-toxic materials,  reducing waste and using recycled materials, water-efficient plumbing fittings,  water harvesting renewable energy sources and a general sensitivity with regard to the impact of the development on the environment.

A focus on light and energy
Technologically advanced systems trap and disperse natural light, which saves electricity. Echoing the green theme, the atrium is designed as a forest-like canopy with South Africa’s most sophisticated retractable sunscreen systems that are intelligently linked to wind and solar sensors. These, combined with state-of-the-art double glazing, control, conserve, store and focus light, energy and heat so efficiently that 115 West Street literally saves hundreds of kilowatt hours each day. Moreover, glazing delivers natural light to the heart of the building through individually designed skylights.

Revolutionary technology
Used for the first time in South Africa, a cable tension system from the United Kingdom (UK) was used for the building’s northwest facade. “This presents a simple solution to horizontal shading,” says Carew. With blinds, he added, there is a question of occupants being subject to unwanted glare, as opposed to this fully automated system that has sun sensors on the roof. Moreover, the system enabled the contractors to use a clearer bubble-gazed glass.

“What is different to this facade is that one can see through the scallops and as a result people have a diagonal working view. The aim was to give workers access to the view for as much of the year as possible. It is not about maximising the view, but optimising it,” Carew noted.

Motion sensors
Motion-sensing activators are used for lighting, which only activates when people are near, while the exterior scallops of the building are a fin-shaped design that implements the natural movement of the sun to ensure lighting and natural shading, which reduces the need to cool down the building with air-conditioning.

Located in the basement, a state-of-the-art grey-water reticulation system draws a steady supply of waste water from the showers in the on-site gym, as well as toilets and water basins. The three filtration tanks can take up to 20 cubic metres of water daily, each running for four hours a day, according to Carew. He noted that the cost and maintenance of the system is one fifth of the potable water costs. Furthermore, a rainwater filter harvests water to wash the toilets and irrigate the gardens, trees and living walls.

A green working space
According to a press release from Alexander Forbes, the 52 trees that were removed to create 115 West Street were replaced with 151 new trees that were integrated into the building’s design and work spaces. “Our staff will enjoy a more natural and healthy environment, with increased circulation of fresh air, reduced heat loads, numerous pause and other plant-filled break-out areas, combined with state-of-the-art work stations and the latest information and building technology,” said Kieswetter.

Energy-efficient transport
The parking area includes allocated bays for energy-efficient cars, car-pooling, as well as bike racks. The building is also located directly across the road from the Sandton Gautrain station.

Immediate and long-term benefits
Also speaking at the official inauguration of the building, Brian Wilkinson, chief executive officer of the Green Building Council of South Africa (GBCSA) said that it was encouraging to see green “iconic structures” being built, as the built sector has a large environmental footprint. “Almost 13% of harmful emissions emanate from the built environment, while it also accounts for 12% of freshwater use. Green building not only cuts down these expenditures, but also holds a number of benefits,” he noted.
According to Wilkinson, green building can save as much as 50% on electricity costs, which bodes well for a company in the light of all the rising power costs. “Further, healthy buildings are also a nicer place to work, and studies have shown that people are 20% more productive in a green building, with less sick days being reported,” Wilkinson said.

Furthermore, the immediate benefits of green design and construction, such as savings on operating costs like energy and water, mean buildings are “future-proofed” from high retrofit costs by virtue of the installation of efficiency measures from the start.

Alexander Forbes received a highly commended mention in the AfriSam Innovation Awards for sustainable construction. This award was made to the contractor, WBHO/Tiber. At the same event, WBHO/Tiber was awarded as the best building contractor for the Alexander Forbes building.

Full acknowledgement and thanks are given to www.alexanderforbes.co.za and www.paragon.co.za for providing the information to write this article.

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