The newly launched Central Square – a large scale mixed-use development in Pretoria’s Menlyn Maine precinct – ups the stakes for sustainable design in South Africa’s retail sector, having piloted a new custom rating tool for Green Star certifications.
Menlyn Maine, South Africa’s first mixed-use “green city”, is based on New Urbanism – a planning and development approach that focuses on human-scaled urban design. Grounding principles focus on walkability, accessibility, close proximity of buildings, and diversity of people and places. The R10billion Menlyn Maine precinct is one of the first developments in South Africa to roll out this approach.
The latest addition to Menlyn Maine is Central Square, which includes a hotel, gym and retail space. Greg Reid, project manager and architect at Boogertman and Partners, says Central Square’s design articulates the Menlyn Maine vision to create a walkable and livable urban environment, and is a vibrant new “city centre” for the precinct.
In line with Menlyn Maine’s sustainability goals, all buildings in the precinct must achieve a minimum 4-Star Green SA Star rating from the Green Building Council of South Africa (GBCSA). To ensure this goal was achieved, a new Green Star custom rating tool was developed in partnership with the GBCSA to assess the Central Square development. The new tool is set to become a benchmark for similar developments across the country.
Menlyn Maine is co-owned by joint investors Menlyn Maine Investment Holdings and the Government Employees Pension Fund, represented by the Public Investment Corporation. As a partner of the Clinton Climate Initiative, Menlyn Maine is one of 16 “green cities” being built in various parts of the world, and the only one in Africa. A “green city” is broadly defined as an urban precinct that incorporates consciousness of its environmental impact, along with the good habits of its inhabitants, to use resources such as water and energy sparingly.
The Menlyn Maine precinct incorporates a residential quarter, offices, a casino, a five-star hotel and an 8000 seat multi-purpose arena. The new Central Square includes a 30 000m2 retail mall, a Virgin Active gym and a new 213 key state-of-the-art hotel built and owned by the Capital Group, which will also host executive apartments. Henk Boogertman, the architectural director of Menlyn Maine Investment Holdings and a main architect in the planning of Menlyn Maine and Central Square, says the developers decided to make Central Square the heart of the Menlyn Maine development. “Most great city centre spaces worldwide have centrally located piazzas where people can mingle, meet, trade from markets, and enjoy exhibitions, functions, festivals and the like.”
Apart from the buildings, Menlyn Maine also incorporates a green belt that runs throughout the precinct centre. On the one end, a large park creates a forecourt to the Sun International Time Square Casino. A smaller park nestles beside the new Central Square hotel, with streets and cycle lanes snaking through the development. In the middle of Central Square, overlooking the planned casino, is a large paved piazza that houses an assortment of restaurants.
FIRST OF ITS KIND
As Central Square is a unique mixed-use development, it was not possible to measure its Green Star rating under any of the existing rating tool categories because they only cover certification of single building types, such as commercial office, retail, multi-unit residential, public and educational buildings. Central Square therefore became the first project to receive a customised Green Star SA rating when it achieved a 4-Star Design certification in August 2016. An application for an As Built rating has also been submitted. “Although other projects are also targeting the custom tool, we are very proud to be the first to achieve it, thus leading the industry with this significant rating,” says sustainability consultant Alison Groves, from WSP|Parsons Brinckerhoff’s Green by Design team. Reid says the basic qualifying criteria for a Green Star rating were incorporated into the design of Central Square very early on in the planning process. “The initial scheme always took cognisance that this was to be a green precinct, therefore ideas such as public space, natural light, and recyclable materials were top of mind.”
All consultants, including lighting and mechanical engineers, strived to include as many green initiatives and technologies as possible from the outset. The Green by Design team then liaised directly with the GBCSA to develop the criteria that would best measure and assess a building of this nature, using the existing Green Star rating tools as a reference. Groves says it was decided to use the structure of the Public and Education Building (PEB) tool, which was the most recently developed measuring tool at the time, to form the basis of the new custom rating tool as it already includes multiple spaces that could be rated. The new custom tool allows for the rating of projects that would otherwise not fit into the existing Green Star rating criteria, Groves says. She expects the GBCSA will continue to fine-tune the tool with the aim of rolling out a standardised custom tool.
One of the features of the new tool is “green leases”, where tenants are held responsible for their energy consumption. Every shop is individually metered in order to control this. “Green leases are growing in importance as the first step in changing mindsets towards sustainability and getting buy-in from tenants for retail, commercial or residential use,” says Groves. Reid says it is not an easy feat to implement sustainability features such as separation of waste, energy-efficient cooling, and daylight harvesting in a retail space. However, discussions with the tenants bore fruit and particularly the anchor tenants responded to Central Square’s push for sustainability. Spar, for example, uses only the latest imported LED lighting resulting in the entire store’s lighting consuming less electricity than one oven, according to owner Peter Arsalides. Similarly, the store’s advanced refrigeration technology cuts electrical consumption by 67%. Spar also uses heat pumps for hot water generation and circulates this water in a ring main – a hot water plumbing loop – throughout the store. The efficiency of the heat pump reduces the cost of generating hot water compared to a conventional system.
Fellow anchor tenant Woolworths also uses LED lighting throughout, even in its freezer and cold room doors. In addition, it installed a 100% natural gas refrigeration system. “Natural refrigerants do not deplete the ozone layer and have a negligible effect on global warming,” says Justin Smith, head of sustainability at Woolworths. “Our natural gas refrigeration also uses less energy. Very few refrigeration systems in the world can offer all of these benefits.” Using online water metering, automatic taps, heat pumps and dual flush toilets saves water. The company carefully considered all their options, says Smith, and believes these selected technologies provide the best value for money. He says the payback periods have been fairly reasonable for Woolworths, as they also bring about energy and cost saving benefits. “We have a number of stores with these technologies, and they are really working well. They have become a key part of our specification for new store development.”
SETTING A GREEN TREND
The Central Square development as a whole also boasts green technologies such as a central chiller plant that includes a Cristopia thermal energy storage (TES) system, highly efficient lighting, high performance glass, while it lets in natural light where possible. Groves says good natural light in the office space and public spaces within the mall helps reduce artificial lighting requirements and provides a pleasant environment for shoppers. The chillers generate chilled water for cooling the Central Square mall, including the offices but excluding the anchor tenants. All the chillers are reversible, so also generate hot water for heating purposes. The TES system – which works in conjunction with the chillers – spreads the thermal energy production over a 24 hour period, shifting the generation of “cooling” and “heating” energy to off-peak periods (night) when the energy demand is lowest and electricty costs are cheapest. This energy can later be used to supplement energy requirements during peak hours (day) or can serve as a backup during a power failure. The TES can save up to 70% of energy costs compared to a conventional HVAC system.
Rainwater from the roof is fed to two large tanks in the basement. This is pumped back up to the centre, where it is reused for irrigation and toilet flushing. “In a water constrained environment, this helps to reduce the consumption of potable water for requirements that don’t need high quality water,” Groves adds. Roof materials were also carefully selected to reduce the urban “heat island effect”. The steel coating with its grey colour reflects more light and heat than a darker coloured material thus reducing the amount of heat transmitted into the building.
Reid believes that an essential sustainable feature for any development should be narrowing the distance required to travel between home, work and recreational activities. “By creating a mixed-use scheme the intent is that people can genuinely begin to recreate in the same precinct in which they work,” he says.
Central Square benefits from being located near key public transport interchanges, such as three Gautrain bus stops, the new BRT bus system and a minibus taxi terminus. Bicycle lanes snake throughout the development, with ample bicycle storage facilities. Bicycles can be chained to custom designed benches which are “disguised” as works of art.
The building is designed according to passive design principles. Reid explains that the facades of the building correspond to the sun conditions on each side of the building. The east and west facades are more solid with smaller openings which protects the inside offices from harsh morning and afternoon sun. The north and south facades are larger curtain walls that are sloped in the vertical plane, Reid says. The specific angle of the glass mitigates glare during sunrise and sunset, and “during the peak of the day when the sun is overhead, it does not shine directly onto the glass. Therefore you get good light but not direct heat.”
The restaurants and shops around the piazza – facing south – have double height glazed shopfront windows to allow in as much light as possible. They are fronted by a colonnade which creates a functional covered seating space – a “theatre of food”. The contractor, WBHO, was held to high environmental standard, adds Groves. “They had to ensure good air quality was maintained, and there was no pollution of the soil, groundwater or surrounding areas. In addition, the contractor was required to recycle a minimum of 70% of all construction waste.”
Reid says the Central Square mall was conceptualised as a “street”. “From extremely modern to historical, the street has an inherent urban character and uniqueness, reminding patrons of a high street atmosphere.” Outside, distinctive finishes that define the architectural character include black facebrick, beige coloured limestone cladding and charcoal tinted Rheinzink (titanium zinc cladding).
Working closely with interior designers DSGN Design, the architects created an interior space that reflects a sense of history. The granite floor tiles on the inside of the mall are complemented by a combination of oak and stucco plastered ceiling bulkheads. The building is crowned by a glass skylight roof which is layered with acoustically treated ceiling panels that allow gentle indirect natural light to spill into the interior spaces.
Art plays an important role in Central Square’s urban design. Sculptor Anton Smit’s artworks are displayed throughout the development and both artist and developers envisage that Menlyn Maine will become the “art hub” of Tshwane. “My work hopes to create a new experience for residents, retailers and art enthusiasts alike – to make art part of one’s daily experience,” says Smit. “The art will provide the opportunity to learn, touch, and ‘feel’ the spirit of creativity.” Smit’s “Spirit of Tshwane” is a main feature artwork of the centre. “Born from diversity, ‘Spirit of Tshwane’ is the new face of the City of Tshwane,” says Smit. Reid believes Smit’s work of art will indeed become a reflection of the spirit that Central Square hopes to inspire for its visitors – creating a vibrant green city hub for the citizens of Tshwane.
WORDS YOLANDI GROENEWALD