LRC Library_Arch. Musau Kimeu
Highlights of the development
Let us see how each space has both met the design brief and blended sustainability with high-tech gadgetry such a centre would demand.
Measuring approximately 50mx40m, the Square acts as the datum, dictating placement of different elements within the site. Its 6m wide paved walkway is finished with a combination of patterned Njiru blue stone, a hard grey and Mazeras stone. Supported on one side by round columns with square bases, the walkway’s roof drains towards the buildings. To the inside of the walkway is a storm water drainage filled with smooth river bed round stones. The central area of the Square is planted with grass and on one comer of the Square is the Fountain of the Professor and the Student. Diagonally juxtaposed is a three metre high statue of Pope Paul VI by Ugandan artist Leonard Kateete; Pope Paul’s papacy lasted between 21st June 1963 and 6th August 1978. From the Square, 13 flag posts are visible on top of the Library entrance canopy. These represent the 9 member countries of the AMECEA, the affiliate members, the University and the Vatican.
With a seating capacity of 3000 users and being the only building in the original brief, the Library building is the focal structure of the development, placed in-between the Conference Hall and the Cafeteria. It is inviting, with a totally glazed framed entrance shaded by a 8.4m high canopy projecting above the entrance floor level.
Raised 2 metres above the natural ground level, the flight of steps to the main entrance gives it a clear commanding sense of entry, while side ramps direct you to the entrance and also to the Lower ground level.
The Lower ground level houses a Bookshop, Left luggage, The University Press, a Multi-media centre and a sunken fountain area. Housed on this floor also is the library’s Acquisition and Cataloguing section, with supplies being
replenished through the loading bay on the western side of the building. Four emergency exits from the fire escape staircases open to the outside.
“The overall openness of the spaces flow seamlessly into the book shelves and the glazed offices unifying the library interiors into one large ‘open space’ and at the same time making it lively and interesting”
The library building has a deep plan, approximately 70m by 43m, with a central atrium. Located on the Lower ground floor, the water fountain and internal garden area is conceived as a ‘pause area’. With its informal seating of easy chairs, it helps to soothe and relax the mind after intense reading sessions. It is sunken and secluded, an area for social activity. Adjacent to the fountain area is the main vertical circulation area, consisting of the main staircase and a scenic lift. The interconnecting modern staircase that bridges the atrium boasts of black granite treads contrasting strongly against the adjacent off-white surfaces. The lift shaft next to it on the other hand provides breath-taking views. When in this part of the city, this building is a must-see.
On arrival at the Library entrance, a children’s library section is juxtaposed on the right side against the circulation desk and offices to the left. An elegantly-cut mazeras-stone clad wall against which the reception and Security control is set brings a warm and natural feel into this lobby. Access is electronically controlled using the latest Radio Frequency Identification (RFID) management system with each user requiring electronic identification and so is the borrowing of books. This RFID is a wireless non-contact use of radio-frequency to transfer data, for the purposes of automatically identifying and tracking tags attached to objects. In addition, the ground floor houses the University Librarian offices, reading spaces, a newspaper lounge area and the Reference section. The newspaper reading section is triple volume, separated from the water fountain by the central vertical circulation.
The First floor houses open reading spaces and book stacks, reading carrels and discussion rooms as well as the Africana section, each manned by reference librarians and their assistants. The Second floor houses additional reading carrels, Humanities and Social Sciences reference collection areas and multi-media space with computers for library users. Above the second floor is the Attic, which was envisaged to house staff reading area, a lounge and an executive boardroom, all opening to external balconies.
In all the reading spaces, ergonomically fit seating is provided with power and internet connected reading tables. The overall openness of the spaces flow seamlessly into the book shelves and the glazed offices unifying the library interiors into one large ‘open space’ and at the same time making it lively and interesting as it lacks the monotony and obtrusiveness of internal walls.
All the offices and open plan spaces are given subtle textures, without overpowering the overall ambience of the LRC. The interior decor is simple, yet it is clearly evident that a lot of attention has been paid to perfecting the intricate details. The architect has played with internal volumes and manipulated them to create a harmonious transition of spaces; with a double volume entry, and 4.2m high single volume reading areas that relate superbly with the adjacent multiple volume atrium.
Whereas columns and beams are finished with con-mix, the atrium vaulted roof has prime-grade podo timber T&G ceiling with the other spaces having acoustic ceiling tiles. Internal partitions consist of aluminium frames with 900mm high scratchproof laminate infill and glazing above.
In designing the Library, three building forms were considered namely, short/deep, tall/narrow and long/thin, all having advantages and disadvantages. From an environmental design point of view, a short/ deep building has the smallest surface area and is least vulnerable to external climatic conditions, but its deep surfaces require constant
artificial lighting, leading to high electricity consumption. On the other hand, a tall and narrow building would have good access to natural light throughout but cost more to build and run e.g. services like lifts and staircases amongst many others. For this site, two long and narrow blocks gave both the required size and good natural lighting possibilities.
By orienting them along the East-West axis, solar gains into the interior spaces were limited. The two blocks were later joined at the sides and the space in-between roofed to form the building’s central atrium.
Lying close to the Equator, the East and West facing facades are subject to strong direct solar radiation throughout the year whereas the North and South facing facades receive direct sun rays for about six months of the year. The environmental architect’s main aim was to achieve thermal comfort in the internal spaces, but at the same time limit
capital and running costs. Ways to limit internal and external heat gains were investigated as well as ways of cooling or flushing out heat build-up in the building’s high thermal mass during day-time using night time ventilation.
Moderating external heat sources
In tropical climates, the major external heat source is solar heat gain through glazing and indirectly from the sky and ground reflectance. The indirect solar gain from the sky and ground reflectance cannot be easily shaded and
therefore the amount of glazing on the buildings was limited. To investigate ways to minimise solar heat gain, a
computer model was used to simulate the solar path, together with various side and top sun-shading devices and to predict internal temperature levels.
Sizes of sun-shading devices were also calculated.
Windows in the Library building are located on the North and South facing facades, with no windows on the East and West facing facades except for lobbies to the wet areas. A combination of high thermal mass ‘250mm thick hand dressed Njiru blue stone walls’ and extensive concrete sun-shading in the Library and Conference hall moderates temperature extremes. The Library interiors are light-coloured to render both natural and artificial light sources more effective. The combination of clear glass, light finishes and Nairobi’s natural bright sky provides good natural lighting in the interior spaces. To reduce heat gain and noise through the roof, 50mm thick Styrofoam was installed throughout the entire roof beneath the roofing tiles and GCI waterproofing. Styrofoam is composed of 98% air and thus has excellent insulating properties.
Passive cooling and ventilation
With a decision to use natural ventilation over mechanical ventilation in all the Library spaces, significant running costs were saved. The chosen design approach was to have air intake through the side windows on the walls and exhaust the used warm/hot air through the roof. To achieve this, a pattern of airshafts on the attic floor and above the roof combined with the atrium, act as thermal chimneys to discharge hot air which enters the building through double louvered panels on the side window glazing on the lower floors as follows:
On either side of the external columns are 600mm wide aluminium double louvered panels with mosquito/insect proof wire gauze in between which run the full height of the windows. To enhance cross-ventilation, the double louvered panels are also included in all the glazed internal partitions. These help to bring in fresh-air into the building.
The library central atrium has a barrel vaulted roof whose central section is raised up along the entire length of the library, 2 metres wide. The raised section is fully glazed with laminated glass to admit natural lighting into the building through the atrium. However, to reduce direct solar radiation through the glazed atrium roof, large aluminium aerofoil louvres have been installed below the glazed roof to sun-shade and cut off glare into the library. On either side of the raised roof are additional louvered openings to aid in cross-ventilation.
During the cool nights, the system continues to operate, flushing out all the stored heat from the building’s high thermal mass using cool night-time air drawn through the slightly warmer building and thus making use of Nairobi’s typical diurnal temperature range of 10°- 15°C.
The Library building is exceptionally lit naturally throughout daytime using the atrium roof glazing and side windows. So well is the natural lighting in the interiors that the users do not need to turn on artificial lights throughout daytime and thus cutting on running costs significantly.
Other green building design strategies used in the Library include the use of elaborate deep sun-shading of all glazed areas. The sun-shading is realised by use of pre-cast concrete vertical elements combined with in-situ concrete horizontal sun-shading elements and a concrete deep roof eave overhang around the Library building. Except for the server room, the entire building uses natural ventilation to provide cooling. Building services such as toilets, kitchenettes, stores, ducts and fire-escape staircases are located on the East and West facing facades. Being non-habitable spaces, they shield the habitable spaces against the morning and harsh afternoon sun. The building uses locally available materials, with low embodied energy, minimal maintenance, non-toxic, those with minimal internal pollution and damage to health and easy to re-cycle or to re-use. People, what more could one ask to eternally solve the lighting and thermal challenges posed by such a brief? If the teaching of this module is not what the Viewpark Towers designers skipped while in college, which one is it?