The Sage VIP Epsilon Building in Pretoria’s Menlyn Maine Precinct is paving the way towards a greener future.
*view the image gallery at the bottom of the page
A cut above
When occupants buy into the advantages of green building practices, the opportunities are endless. This was exactly the case when Sage VIP Payroll and HR, a supplier of payroll and human resource management systems, recently moved into its new energy-efficient, environmentally-friendly office space. The Sage VIP Building is the second building to be developed in Menlyn Maine in Pretoria’s eastern suburbs, which is set to be South Africa’s first green precinct.
Sage VIP Epsilon Building
- Architect: Boogertman & Partners Architects
- Interior architect: Boogertman & Partners Interior Architects
- Project manager: Pro Arnan
- Quantity surveyor: Pentad Quantity Surveyors
- Civil and structural engineers: WSP Structures Africa
- Mechanical engineers: C3 Climate Control Consulting Engineers
- Consulting electrical engineers: Rawlins Wales & Partners
- Wet services engineers: SJ Franklin
- Sustainability consultant: WSP Green by Design
The building’s green attributes include:
- Harnessing natural light.
- Adjusted external lighting.
- Clever air-conditioning and lighting.
- A building management system.
- A vegetable garden on the roof.
- Occupancy sensors.
- A recycling programme.
- Convenient and responsible transport options.
- The use of environmentally-responsible building material.
The building received a Four-Star Green Star SA – Office v1 “design” rating, which recognises and assesses best green building practices and scores them accordingly. According to Anton van Heerden, managing director of Sage VIP, the building’s green status is in line with the company’s core values: To care for the community and the environment and, as such, the building’s design development was a collective effort. Gerhard Boer from Boogertman and Partners, who was the lead architect on the project, says: “From the inception stage we worked with Sage VIP as they were interested in the various green concepts.” In many instances the building was customised to the tenants’ needs. Van Heerden says: “There were certain aspects that we weren’t willing to compromise on, such as the amount of parking and bright lights in the boardrooms, which was made up by other green design elements.”
According to Van Heerden, the initial capital expenditure on a green building is 15% higher than conventional office space. However, as the company has a ten-year occupancy plan, the higher capital expenditure is viewed as a long-term green investment. Van Heerden says: “According to conservative estimates we will get our money back within five to six years.”
The clean-lined black-and-grey building was designed to be simplistic in nature. Key aims were to limit maintenance costs and to integrate sustainable design principles in all aspects of the building’s design.
Boogertman & Partners’ objectives and guiding principles in the design response to the Epsilon Building included integrating the building into the greater Menlyn Maine Precinct context (such as focusing on pedestrian-orientated design), ensuring viable interaction between public and private domains, as well as facilitating activity-driven, and interactive zones.
The building design
An external gathering space at the building’s entrance extends to the interior with a multi-volume, atrium cum reception area that radiates with natural light which filters in through a glazed-glass skylight. This seamless design clearly highlights the concept of creating connectivity within a visually permeable space. On the ground floor, the periphery of the building includes semi-public areas, training facilities, meeting rooms and the main canteen. These functional areas form an envelope to the main atrium. Boer says: “The intimate atrium is a focal space that forms the heart of the building and encourages face-to-face interaction.”
The first to fourth floors are zoned for private office use. Currently VIP occupies the ground to third floors. “Plans are underway to sublet the fourth floor until the company needs the office space,” says Van Heerden. The roof level with its panoramic views is used as an open-air recreational space, as well as a high-rise vegetable garden. Van Heerden says: “The vegetables are cultivated for the canteen kitchen, while the surplus is sold to the local greengrocer.”
The following green principles were incorporated into the Epsilon Building:
- Harnessing natural light: Consideration was given to both passive and sustainable design principles. The building uses external shading devices such as aluminum louvers and overshadowing by balconies to help shade the windows from direct sunlight. Care was taken to limit windows on the eastern and western facades, as it is more precarious to treat the sun’s low angle in these areas.
- Internal lighting: The building uses highly efficient lighting to save energy and to provide a comfortable environment for occupants. All linear fluorescent lights are efficient T5 lamps that use electronic ballasts. The lighting design provides the required illuminating for the office (350Lux), but without creating an overly glary environment. Circulation areas, common areas and bathrooms all have LED lamps that can be dimmed. The main office areas as well as the bathrooms and storerooms use motion detectors to ensure that lights do not burn unnecessarily in unoccupied what????
- External lighting: Highly-lit buildings have a detrimental effect on the behavioural effects of nocturnal creatures. Therefore all lights on the facade are dimmed to minimise light pollution and are positioned to avoid upward light spillage into the night sky.
The office areas receive 150% more fresh air than building regulations require. Two fans on the roof pump fresh air into the building. Fresh air is pumped directly into the in-ceiling fan-coil units that condition the air before it is distributed into the occupied space. Constant volume dampers regulate the airflow to each zone. The ventilation fans are fitted with seven-day timers, so that they do not operate during unoccupied hours. The same principle applies to the toilet extraction systems.
The fresh-air ventilation system has been designed to provide a minimum of 12,5 litres/second/occupant, based on an occupancy of one person per 15m². This represents the 150% increase of fresh air when compared to the minimum legislated ventilated rate.
- Air-conditioning and heating: The air-conditioning system uses a refrigerant with zero ozone-depleting potential. Each area is monitored with sensors that have automated the control of the environment?? Consider revising. Heating is also gathered from the atmosphere on the roof and the heat from the hot-water pipes.
- Thermal comfort: Each zone is equipped with thermostatic sensors, so that the air temperature can be adjusted to maintain a 22ºC ambient temperature. The conditioned air and fresh air supply is distributed evenly into each zone using constant-volume diffusers. Blinds have been installed on all facades to prevent eye strain from the glare of direct and indirect sunlight.
- Rainwater is captured on the roof and is stored in 100 000-litre storage tanks in the basement. Van Heerden says: “The water is used for general water usage, such as flushing the toilets and irrigating the roof garden.” Water flow has been established through the earth’s gravity. Hot water is heated on the roof through insulated tanks and is made accessible through an insulated closed-loop circulation system. Moreover, the irrigation system’s water will also be captured and circulated back into the tank. The aim is to save 4,5-million litres of water per year.
- • Domestic hot water: A central hot-water installation at roof level consists of two insulated hot-water storage vessels, each with a 1 000-litre capacity. The water is heated by two 12kW output (3kW input) air-to-water-type heat pumps. Every hot-water usage point has immediate access to hot water. This prevents water wastage that occurs when draining the “dead leg” of cold water.
- • Rainwater harvesting: The building is equipped with a 70 000-litre rainwater storage tank. This tank supplies a 20 000-litre WC flushing tank and a 10 000-litre irrigation tank. Thus the building has a total storage capacity of 100 000 litres. This water is used instead of potable or municipal water for flushing the toilets and irrigating the gardens.
The roof is designed to capture and attenuate bulk rainwater. The water flows through grates on the rooftop into the basement rainwater tank via a siphonic drainage system. The water is processed through a treatment system to ensure that no bacteria and sediments are present in the water before the water is pumped to the roof tanks. Small pumps are used to pump the water from the tanks to the ablution facility on the fourth floor while the gardens and ablutions on lower levels are purely pressurized by means of gravity..
Building management system
The Sage VIP Building boasts a building management system (BMS) that monitors the electrical demand, temperature and water usage in all areas of the building. The information gathered will be analysed and compared with historic data and will alert the facilities manager when something is out of the ordinary. According to Van Heerden, this beneficial system monitors energy and water consumption and highlights areas where these resources are wasted. The real-time system also monitors the lifts, fire-protection, CO² and CO levels in the basement and landscaping systems. Van Heerden says: “This allows for faster response times to sort out any snags.”
Occupancy sensors are positioned in the office space at a density of no greater than 1/100m². Motion detectors automatically switch lights on where there is movement. The sensors are also linked to the air-conditioning system to avoid unoccupied space cooling. This ensures a comfortable and controlled environment that saves on energy consumption. Each floor is divided into four zones with a key switch at the entrance of each zone so that the lights can be switched on manually.
Close to 80% of office waste is recyclable, and recycle bins are placed in the pause areas and central points to enhance recycling efforts. A waste chute has also been built into the cafeteria and kitchen in a bid to speed up the recycling process.
Prime parking bays are reserved for employees who carpool, as well as for motorcycles. Menlyn Maine boasts its own cyclist sidewalk that aims to promote more cycling. The Sage VIP Building offers access-controlled bike racks, with change rooms that offer lockers and showers. Gautrain bus and taxi stops are also located close to the building to encourage public transport.
Rooftop vegetable garden
When stepping out onto the roof, one is surprised to find a rooftop vegetable garden that also incorporates ample recreational space for employees. Fresh produce is used in the canteen and restaurant while the surplus is sold to local greengrocers. The high-rise mini farm expands the building’s green footprint by focusing on sustainability.
Volatile organic compounds
All the paint, adhesives, sealants and carpets used in the Sage VIP Building comply with South African Green Star standards. This helps to eliminate the sensory irritation that gasses and vapours in new buildings may cause. The carpets are also 100% recyclable and hardwearing.
The concrete that was used for the new building is much stronger? In addition, 30% less cement was used – the cement was combined with fly-ash and waste products from electricity production and steel furnaces (GGBS). The steel that was used for the building is 95% recycled, which significantly reduces the environmental impact. All the timber that was used for the project was sourced from a certified forest that promotes responsible forest management practices. The use of any ozone-depleting gasses has been minimised, while the use of polyvinyl chloride (PVC) was reduced by 60%.
How does mechanical air-conditioning and heating work?
Cooling and heating
Climate control is achieved through the Chiller Assist Thermal Energy Storage (CA-TES) chilled water system. The air-conditioning plant consists of one air-cooled reversible heat-pump chiller and one cooling-only air-cooled chiller that are located on the building’s roof. The chillers use the refrigerant, R410a, which has a zero ozone-depleting potential.
The chiller plant produces chilled water for cooling. The reverse-cycle capacity is used to heat water in the winter. Water is an effective medium for transferring heat. As such, it is delivered in separate hot and chilled water-piping systems to the four-pipe fan coil units (FCU) located in the ceiling voids of the office areas.
The modulation of hot and chilled water supplies to the FCUs ensure heating and cooling. This is based on the occupied zone’s requirements. Constant-volume diffusers blow air-conditioned air into the spaces. The diffusers can be repositioned if the offices’ layout should change in future.
Each floor of the office area is divided into several air-conditioning zones. On each floor, four perimeter zones are located at the four exterior facades of the building next to the windows. These perimeter zones are exposed to direct sunlight and radiant temperature changes. As a result, the temperatures in the perimeter zones fluctuate throughout the day. The air-conditioning system is designed to provide cooled and heated air through water that is piped to fan-coil units using a four-pipe closed loop system. The heat that is produced from the water medium is balanced to deliver the ideal temperature conditions for the individual spaces.
The building uses a phase-change material called Christopia to reduce the peak energy demand. The thermal storage tanks in the basement are “charged” at night between 21:00 and 09:00. Night-time electricity drives the chillers to convert the phase-change material into a solid state. During the day, when the demand for air-conditioning peaks, the building uses the stored thermal energy in the tanks to produce cool air for the air-conditioning system – instead of using expensive electricity. This effectively reduces the building’s peak energy requirement by 50%.
The benefits of thermal storage include:
- Decreasing the size of the refrigeration units by 30%, refrigerant quality, peripheral units, subscribed demand, equipment rooms, maintenance, running costs, CO2, SO2, NOx emissions and equipment replacement costs.
- Thermal energy storage helps to ensure a cleaner environment by increasing plant capacity, reliability and output, as well as the service life of the refrigeration units.
- Moreover, thermal energy acts as a back-up system and KWh usage can be shifted from peak hours to off-peak hours. This saves energy and controls energy demand.
The bigger picture
The Menlyn Maine Precinct in Pretoria’s eastern suburbs is being designed to be the first “green city” in South Africa. The design is based on new urbanism principles that combine a vibrant urban character with sound environmental principles. Urban design consideration is given to connectivity, mixed land use, legibility, walkability, robustness, visual appropriateness, biodiversity and security. According to Boer, one of the key aims of the precinct is to encourage pedestrianisation and accessibility. “Therefore all the buildings are built on the building line.”
When completed, the mixed-use development will include up-market residential, retail, dining and luxury hotel spaces alongside office developments that overlook 5 700m² of scenic parklands. All buildings within the precinct target a minimum of a four-star Green Star rating. The overall precinct will target a LEED neighbourhood rating, and the city will target the Clinton Climate Initiative that recognises city developments that strive to become climate-positive.
Full acknowledgement and thanks are given to Boogertman & Partners and Sage VIP for providing the information to write this article.