In the recent 10 or so years, high rise buildings around Nairobi have started embracing glass as an external walling element.
Apart from the clean, sleek aesthetics, glass also has several other advantages.
Buildings such as National Bank building along Harambee avenue have a double glaze facade, with 2 layers of glass around 300mm apart.
This helps to reduce air conditioning whereby natural air is let to flow in without causing life effect on papers internally.
Double glazed glass facades also insulate the interior of the buildings well since the air trapped in between the 2 layers of glass serves as an insulator from external vagaries of weather.
Such designs are more common in European countries.
High rise buildings external facades should be designed such that its easier and friendlier to clean the windows from inside and outside . The standard framing for high rise building glass is aluminium, which is light weight but strong enough to support the glass. Care should be taken at installing to ensure that the glass and its frame are rigid enough so as not to fall and injure pedestrians on the lower floor levels.
Highrise buildings have to be designed to withstand huge wind loads so the glass has to be thick enough to support the wind loading. A minimum of 5mm thick to the average of 10mm thick glass is used.
The glass is laminated with a thin layer of resin so as to provide strength and support in case of fracture, holding the glass pieces to prevent them from injuring occupants and pedestrians.
In some cases, toughened glass is used. Toughened glass crumbles into granular particles in case of fracture, similar to car windscreens on impact. The toughening encloses alot of energy inside the glass such that when broken, the energy is released in form of small particle like granules.
Modern laminated glass.
The new type of glass used for high rise structures is made up of 2 lalyers, around 5mm thick each, with one layer coloured, while the inner layer is transparent. In between, there is a thin layer of material which has insulation, anti UV Properties embedded within it.
There are Kenyan laminated glass manufacturers who can embed images and even clothes in between the 2 layers to create the desired pattern.
Embedding with leaves and grass, for example, is a method used to create bonding with nature on laminated glass walling used for bathrooms in game lodges.
In some cases, where high insulation from the sun is required, in between the 2 laminated pieces of glass, a thin layer of Argon gas is set up to act as insulator.
Building intergrated PhotoVoltaic Facades are external glass walls of high rise buildings that have solar panels incorporated in them. These generate solar electric power to be used within the building.
In between the 2 layers of glass for lamination, photovoltic cells can be incorporated inside the layers to generate electricity.
Architect Francis Gichuhi Kamau.