Green Building Rating

Green Star Rating System

How a Green Building Rating is achieved

Building Example: Upper Grayston Block E
5-Star Green Star SA – Office V1-As-Built Rating | Achieved in October 2012

For those who may be interested in what the main elements of a Green Building are, we include hereunder a summary of issues which are addressed specifically in Upper Grayston Block E building which has achieved a 5-Star As-Built Rating -Achieved in October 2012.

About the development

During 2012, Bryprop developed Block E in their Upper Grayston Office Park and set their sights initially on a 4-Star Design Rating under the Green Building Council of South Africa Rating system.

This was achieved early in 2012 but it was clear at that stage that it was feasible during construction to add further elements to the design and construction such that a 5-Star As-Built Rating could be targeted. This was achieved during October 2012.

With the achievement of the 5-Star As-Built Rating, once again the points achieved were so close to a 6-Star Rating that it was decided that for the next building (Block F) a 6-Star As-Built Rating would be targeted.


The Green Star Rating strategy, executed for Upper Grayston Blocks E & F made provision for environmental principles to be implemented from project inception. Demolition and construction waste streams were managed and 93% of all waste was recycled and reused, obviating waste from being disposed of to a land fill site.

Building Tuning

As a condition of contract with all contractors and subcontractors, building tuning was employed. This entailed commissioning of all building services after practical completion. Monthly monitoring was required for a period of12 months after practical completion followed by a full re-commissioning after 1 year.

Building Users Guide

In order to maintain and support Green Star Building best practice, a Building Users Guide was developed. This is for use by building occupants enabling them to optimise the building’s environmental performance.

Indoor Comfort Level

The indoor environmental quality is carefully controlled in Green Rated Buildings the well-being of occupants. This includes the introduction of the following:

  • High percentage of fresh air
  • Air change effectiveness
  • Day light penetration
  • Thermal comfort levels
  • 80% external views
  • Glare control through external shading devices

A high quality of light is maintained through the installation of 100% high frequency ballasts and the maintenance of an average lux level of 400.

Air Quality

The air quality inside the building is enhanced by prohibiting smoking and the installation of a tenant exhaust riser to mitigate pollutants associated with printers and photocopiers. In addition only low volatile organic compounds were specified for paints, adhesives, sealants, carpets etc.

Energy Monitoring

The energy utilisation of the building is separately monitored for the lighting, power and air conditioning. The consumption data is displayed within the building and made available on line at

In addition individual tenant information can be accessed and building occupants can analyse live metering results on an hourly basis.

Mixed Mode Air Conditioning Approach

Prevailing climatic conditions of Johannesburg allow 61% of the building’s operational hours to be within the temperature and humidity range required for natural ventilation. In Upper Grayston Block E therefore, the building takes advantage of this through the utilisation of a “mixed mode” ventilation system. Mixed mode refers to a hybrid approach to space air conditioning that uses a combination of natural ventilation from openable windows combined with an air conditioning system. This is regulated through a green light/red light system that is connected to a thermometer. A series of red-green lights are strategically placed within numerous dedicated areas to be visible to building occupants within the building. The thermometer monitors the outside air temperature and when it falls within a certain range a green light is shown that indicates that natural ventilation is feasible to competently ventilate the office area through openable windows. Energy consumption is therefore reduced accordingly. When the light turns to red, building occupants are advised to close windows and operate the air conditioning system in order to achieve optimum comfort levels.

Alternative Transport Modes

The buildings also encourage alternative transport to reduce carbon omissions associated with automobile commuting. This is done by providing preferred parking spaces for car share, hybrid and alternative fuel vehicles, motorbikes, mopeds and scooters. The building additionally accommodates cyclist’s facilities within the building. Building occupants are made aware of mass transport facilities within close proximity of the building by being informed of facility locations, service times and frequencies within the Building Users Guide which is issued to all building occupants.

Water Consumption

Further use of energy efficiency plumbing fittings and a grey water harvesting system means that potable water consumption is reduced by 60% over a normal commercial building. Water meters have been installed for all major water uses within the building and consumption data is displayed and made available to building occupants along with the energy metering data. The live metering can be analysed and can indicate any abnormal water consumption due to leaks.
The buildings have would also have also made use of Keriscaping Xeriscaping thereby reducing the water consumption utilised for irrigation purposes.

Building Materials

By efficiently managing building materials and selecting reused and recycled materials the project successfully reduced the embodied energy associated with resources and resource depletion of materials used to develop the office block. Portland cement quantities have been reduced by 48% as an average across all concrete mixes. The building is predominately a reinforced concrete structure and 100% of the reinforcement utilised has a minimum of 90% recycled content. Additionally 68% of all steel by mass has a recycled content of 60%.

PVC Minimisation

The use of PVC in the building is reduced by 47% minimising the global human health implications caused by the chemical components necessary for the manufacturing of PVC.

Timber Use

50% of the timber comes from a sustainable source including the formwork used by the contractor and 20% of all materials used for the construction of the building were locally sourced within 400km radius of the site.


In terms of land use and ecology, the chosen site for the development minimised the impact that the construction would have on the ecological system and biodiversity as it fell within an existing Municipal urban edge and 100% of the site had previously been developed.
In addition the developers specified hardscape and roofscape materials which reduced the urban heat effect of the building on the micro climate and wild life habitat.

Ozone Depleting Substances

All refrigerant gases and fire suppressants and insulants associated with the buildings were specified to have a known ozone depleting potential of zero.


Water runoff has been minimised and therefore reduced pollution of natural water courses occurs.
Light pollution was also taken into consideration and the lighting design of the building limits light pollution into the night sky.


As a summary, Bryprop has developed the ability to economically bring on stream energy efficient and sustainable office building