Orientation of a building refers to the direction of the normal to the long axis. For example, if the length of the building is north-south, its orientation is east-west. The chief purpose of orientation of a building is to derive physically and psychologically comfortable living conditions inside the building. The orientation will provide the maximum benefits from the elements of nature such as sun, wind and rain.
In other words, good orientation means proper organization of plan units of the building in relation to the natural causes like rain, sun, wind, etc. Poor orientation of the buildings results in discomfort conditions inside the building. Although needed comforts can be created by mechanical means, they will lead to extra cost.
Factors Affecting Orientation
Factors which may affect orientation are as follows:
- Solar radiation
- Clouds
- Prevailing winds
- Rainfall
- Surrounding site conditions
1. Solar Radiation
Solar radiation is directly related to temperature. From the solar radiation point of view, the orientation should be such that the building as a whole should receive the maximum solar radiation in winter and the minimum in the summer. Hence, it is necessary to know the path of sun’s movement throughout the year and its relative position with respect to the locality.
2. Clouds
Clouds reduce the direct radiation from sun. It is thus desirable to take note of the cloudy periods in a year. Sun protection may be provided accordingly.
3. Prevailing Winds
Prevailing winds minimize the adverse effects of high humidity and high temperature. Thus for the purpose of orientation it is necessary to study the velocity and direction of the wind periodically. It is generally accepted that variation up to 30° with respect to the prevalent wind does not materially affect the indoor ventilation inside the building.
4. Rainfall
The intensity of rainfall and the entire monsoon period should be known so as to decide the orientation of the building and also decide about the structure.
5. Surrounding Site Conditions
Location of the site, either rural, urban or sub-urban, also plays a role in the orientation of a building. Further, the surrounding greeneries or some factories, etc., are to be taken into account while fixing the orientation of the building.
Orientation Criteria under Indian Conditions
Major factors which control orientation of residential building are solar heat and humidity. Climate-wise, Indian climatic conditions may be divided into hot-arid zone and hot-humid zone.
1. Hot-Arid Zones
Such zones are also called as dry arid zones which are found mostly in the interior of the country away from the coast. Hence, to get the comfort, removal of hot air through the roof, doors, windows, etc., are to be thought of by proper orientation. North India and Central India fall under this zone.
2. Hot-Humid Zones
Such zones are also called as wet zones which are found generally along the coastal belts. Here, apart from providing opening for circulation, rain-protection measures also should be considered during orientation. West coast regions, east costs regions and Bengal fall under this zone.
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