The 6 Star Rated Allan Gray Building 

The Allan Gray office building in the V&A Silo districts is the first 6 star green rated office building in South Africa. We were given the opportunity to go to see the building and were given a presentation on its various Green Building Features and Initiatives. The building is very modern, open spaced and impressive. 

The first thing we were told about was its Double Skin façade. 

The outer layer of the building consists of 2 layers of glass. The initial reason was due to the heat penetration from the sun which can be intense. The 2 layers help deflect the sunlight but the sun can still be too powerful and therefore they added a blind. The blind makes use of a sensor which looks at the warmth and strength of the sun and automatically adjusts the blinds accordingly to keep the building cool. The facade also contains vents on the top which are open to allow hot air to escape during hot days and can be closed to contain the hot air to warm the facade on cold days.

Their airconidtioning system is also unique.

In the Allan Gray Building the fresh air comes through the floor rather than from the roof. The floor is raised around 45cm and the space is used for the air duct and for power supply. This system uses less energy than a conventional unit and has the added benfit as the air coming from the floor dissipates the heats and germs in the room and goes through the roof. The system also producers fresh air which is monitored by CO2 system. This system measures the CO2 and oxygen levels in the building and increasing the fresh air supply to pump oxygen into the building which helps productivity. The more oxygen, the better the brain works and the better the productivity.

This is also done automatically though the BMS system and once CO2 levels reach 680 parts per million frsh air is pumped into building. For example while in the auditorium the more people present the more CO2 would be produced in the room and the BMS system would automatically open the vents to allow for fresh air to be pumped into the room.

The BMS system also makes sure that the temperature in the building is between 21 and 22 degress all year around. The indoor pressure in the building is also monitored to ensure that energy efficiency is not lost. There are further sensors on the roof which look at wind speed, humidity and temperature. Macro levers on roof are used to keep positive pressure on building. Higher pressure inside will maintain the hot air. Rain fall is another issue which is enhanced by the wind.

Cape Town is know for having erratic wind behavior. Therefore the wind sensor and look at wind. If all criteria is met ie wind speed, amount of rain, wind direction etc, they will close the levers to stop the driving rain. The wind can be so intense that the building has already lost 2 wind sensors so far. 

Another great initiative is their Sea Water plant which is in Basement Parking Level 1.

Cape Town is infamous for its cold ocean water and the building uses this to its advantage. The Allan Gray building actually utilises the cold water for its coolers in the air-conditioning system! To prevent corrosion the sea water is treated with a catalyst to keep corrosion away and keep chillers cool. The sea water is cooler in the summer months than it is in the winter months which is also great for the building! This sea water cooling system is also cost effective because the chillers take up most energy. The sea water pump also has a sensor where if there is no sea water the system will automatically shut down and send the FM a sms.

Th building also includes a gym and a full time dietitian. They also try and give back to the community through their recycling scene. They use the left over food waste from lunch and convert it into compost which they donate to a school in the near by informal settlements. The school then use this compost to grow mushrooms which they sell at food markets.

At the end of the day the Allan Gray building in the Silo District is a must see for any Green Building enthusiasts! Its incredible how they have incorporate the use of sea water for the air conditioning and how they give back to its surrounding areas.