By Arch. Eric Loki David
The Nairobi Municipal Regulations were published on the 16th of April, 1900, creating a committee that was to manage the town. This committee which later grew into a council contributed a lot in shaping the city’s architecture, with the spearheading of the construction of some monumental buildings like the Nairobi City market and the City hall building in the 1930s.
In the 1920s, Nairobi was developing in many directions at once with the expansion of its boundaries and the improvement of the central area. There was a need for a municipal market of modern design and competitive designs were called for locally. In 1932, the Jeevanjee’s market, which stood along Gulzar street (now Monrovia street), between Stewart (now Muindi Mbingu) and Sadler (now Koinange) streets was brought down and replaced by a new market (current the city market) along Stewart street. The building consists of the main market hall, offices and low rise market stalls.
An almost carbon copy of the Nairobi city market in Nairobi is the Lawrence Hall, one of the two Royal horticultural halls in London which has similar vaulted ceilings and Art Deco interior features.
This building was awarded a gold medal by the Royal Institute of British Architects for its dramatic architecture. It was constructed between 1925 and 1928 (4 years before the city market building in Nairobi) and was designed by the partnership of Easton and Robertson (almost certainly the same architect for the city market) The tall parabolic arches which begin as square piers are credited to Easton, derived from the reinforced concrete work of Hennebique and Freyssinet. The hall was registered as a Grade II* listed building in England in 1983.
Green when ‘green’ was not the style of the day
Provisions for Thermal comfort
An in depth study of the building shows serious environmental responsiveness which came about out of necessity (the city barely had any power to light and cool any building during the day as of that time!) rather than the need to climb the high green moral ground! The following outlines the various strategies adopted to achieve a passive building that still works
Building orientation: The buildings orientation was governed by the street layout. To minimize heat gains through solar radiation, all windows are placed on the Northern and Southern facades.
Use of courtyards: The market uses a series of courtyard which surround the main hall. These courtyards allow for cool air to get into the facility providing sheltered outdoor spaces.
Pyramidal form with shaded glazed windows: The main hall has a pyramidal form made possible by the use of reinforced concrete arches. Such a form would have resulted in a high exposure to solar radiation but its countered by the use of deep sun shading fins.
Shading of the main entrance: This is located on the eastern side and is sheltered from the hot afternoon sun by the high building mass on the western side.
Low-rise mass: The market building is has a relatively low height providing a comparatively smaller surface area for heat gains. Tall buildings experience higher heat gains.
- Light coloured paint on the outside surfaces: The market building is painted cream-white and this helps reflect most of the suns radiation.
- Extensive use of concrete: This material provides a high time-lag keeping the interior space relatively cool even when outside temperatures are highest
Provisions for daylighting
Building form: The stepped roofing provides external light shelves: The exposed concrete arches and slabs reflect light into the interior space breaking it into even diffuse light. The light colour of these elements increase the lighting levels too.
- Reflective white paint: This is applied near the stalls level allowing for light reflection and propagation into the good’s displays.
- Use of clear glass: The windows have clear glazing that allows adequate light into the market
Provisions for Natural ventilation
Site Layout: The location of the facade with entrance openings and ventilation gratings on the windward side directs wind flow onto this facade allowing for air movement into the building. This results in cross ventilation as the with openings on the other side.
- Pivoted window openings allow for air movement into the main hall. Their location on opposite sides also boosts cross ventilation.
- High louvered windows allow for stack ventilation with warm air rising and getting out through the louvers and allowing for cool air to get in through the lower openings
This short analysis of the Nairobi City Market building in Nairobi affirms some salient facts: that ‘green architecture’ is nothing new; that environmental design issues have always been part of architecture even in our short recorded history; and that Nairobi’s climatic conditions provide a near perfect platform for low energy building design. The interesting fact that every architect and developer seems to deny in this city is that ….. ‘Anyone will always find comfort standing under a leafy tree anywhere in this beautiful city of ours; you will always experience a constant breeze and shade; even in the rain! You only need to walk into some of the (perceived to be better) glass buildings of our recent past and everything changes!