|Climate Responsive Building - Appropriate Building Construction in Tropical and Subtropical Regions (SKAT, 1993, 324 p.)|
|3. Design rules|
The main points:
· Collect information about the
local climate factors and the requirements of the user.
· Analyse this information.
· Develop the appropriate design concept.
When planning any new construction, many factors have to be considered. First of all the functions of the building have to be defined which have a primary influence on its type, form, size and layout. The requirements or needs of the user - such as his expectations with regard to comfort - are important determinants.
Factors which may impair the safety of the building are very important. Amongst these are earthquakes, storms, floods and tidal waves.
Economic aspects also influence the design and determine the technical possibilities and standard of building.
The adequate application of the available local resources and materials has to be taken into account.
A major component are the prevailing climatic conditions insofar, as they influence the indoor comfort conditions. These are the main subject of this publication.
Climate is formed by
· solar radiation
· temperature and its fluctuations
· air movement
· air pollution
· sand and dust
General information about the climate of a country can usually be obtained from meteorological stations. The particular microclimate at a given site may however differ substantially. It is important, therefore, to observe local conditions.
It is also important to bear in mind, at what time of the day or night, or during which season, the structure will mainly be used.
The basic steps in the design approach are:
· Information collection about
the factors listed above.
· Analysis of collected information.
· Development of appropriate design measures.
With an appropriate design and the selection of suitable materials, a natural form of climate control can be achieved. By being merely self-regulating, this control provides, to a great extent, protection from the occasionally hostile environment.
Compared to solutions employing technical equipment, such natural means of climatization are usually very economical solutions, both in terms of construction and running costs. Nevertheless, the use of modern technical means is under certain circumstances unavoidable in trying to meet todays requirements for adequate comfort.
New building concepts
It is necessary to develop new building concepts which include essential energy and climate considerations, but are also linked to the functional, physiological and socio-psychological requirements of todays society.
This chapter illustrates the possibilities and methods for a natural form of climate control. It provides general recommendations and rules: in the first part, such rules which are valid for tropical and subtropical regions in general; and in the subsequent parts, for typical types of climates.
In some cases, the local conditions do not correspond exactly to the typical climates described. The rules require a meaningful interpretation, and sometimes compromises will be necessary.
Limitations of passive means
With the technology available, the majority of responses to harsh climatic conditions has been the creation of artificial environments, leading to a complete dependence on electrical power. A number of mechanical devices generating additional heat have been introduced into homes. With the increasing interest in tropical regions, however, much research has been done to improve the design and materials of the different building components (walls, roofs, openings, etc.) so that this dependence may be reduced.[ 124 ]. Nevertheless, it seems almost impossible to fulfil todays higher requirements and create a comfortable, cool indoor climate for living and working during the hot season with only traditional methods and without additional technical means. Where sufficient water is available, it can contribute to cooling by integrating landscaping into urban design and buildings.
In general, active and passive heating of a building is easier than cooling. Nevertheless, for ecological reasons, burning of wood should be reduced in many regions.
In many places today, a wide choice of building materials is available to meet specific needs, but they must be tested and selected carefully. [ 106 ]
Traditional structures and materials may not be suitable in hazardous conditions such as earthquakes, floods and heavy precipitations. Occasional storms can generally be disregarded when designing for comfortable indoor climate. However, for safety reasons, they demand a firm structure.
One of the main problems of building in the long run is proper maintenance. This aspect must be considered in the choice of materials and construction details.
The human factor
Measures to improve the indoor climate are manifold. Some of them are purely connected with the selection of a suitable site, planning, layout arrangements and construction details. Other measures involve the inhabitants, who should take an active role in the operation of the buildings, e.g. by opening and closing windows at the appropriate time, by sprinkling water, or using movable shading devices etc.
Although the second type of measures - using humans in an active role - may appear more effective than purely structural measures, the latter are usually given a higher priority. It must not be overlooked that humans often behave differently from what the designer expects them to do. Also, a proper understanding and awareness on the part of the inhabitants cannot always be relied upon. Sophisticated and complicated solutions often fail due to such human factors.
Learning from tradition
The principles of thermal control through the proper use of structure and materials are well illustrated in traditional buildings which meet the demands of the climate. However, purely traditional solutions also assume a continuity of lifestyles and kinds of work, which seems rather unlikely in many regions. Particular solutions, settlement and building forms, also using multi-story structures, have to be found for todays urban and traffic situations. A combination of traditional knowledge and advanced technology may therefore be necessary.
A good method, as an approach towards a design concept is to analyse traditional settlement patterns and building types. In addition, settlements are influenced by many social and cultural factors, and usually respond in an optimal way to the local conditions, giving many useful indications. This is true, especially for solutions aiming at natural climate control. Factors to be taken into account are the use of local construction methods and available materials, and the technical ability of the local builders.