India has a predominantly tropical climate ranging from the hot and humid climate in the east and north eastern states, hot and dry climate of the central and western Indian plains, to the cold climate in the northern regions.
Orientation of buildings to direct sunlight and to prevailing wind direction is an important factor to be considered in the tropics where temperatures in the shade can reach as high as 45°C.
Orientation of Buildings:
In very hot climate buildings will have to be cooled in summer by artificial means. Nevertheless, even in hot climate, it is not always necessary to use extensive artificial cooling. Some natural cooling is possible by building orientation and design.
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The design of the buildings can be carefully planned to derive maximum natural cooling and thus reduction in energy consumption.
Natural ventilation aided by forced air circulation by fans is adequate in most instances, with recourse to air-conditioning only where inescapable.
The directional orientation of buildings and their placement so as to shade one another is of importance. The architect should study the shadows cast by the sun to maximise this benefit.
Effect of direct sunlight striking the buildings from the east or west at a low angle is very harsh. The effort should be to confine it to the end walls.
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This is achieved if the buildings are oriented to face their long sides north and south or northeast and southwest. Sun falling on the buildings from north or south can be controlled by louvers or awnings.
The design of building for comfort in a hot and humid climate is different from those in hot and dry climate.
In a hot and humid climate, forced circulation of air aids in natural cooling, Air movement through the building and past the bodies of the occupants is the objective.
Therefore, the building should be open, and oriented in such a way that even a slight breeze can pass through the building to cool its insides.
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This is of course aided by circulation of air by fans. A high concen-tration of buildings is not possible in hot and humid climate without the installation of air- conditioning. For effective natural ventilation and cooling, the buildings should be spread out.
In hot, dry climate the nights are cooler though the temperatures during the day may reach fierce levels. The building design should permit protection of the occupants from the intense heat during the day.
To some extent, building with heavy thick walls and small windows serve this purpose, where heat is absorbed by the heavy walls during the day time and dissipated during the night, and the small windows minimise the amount of radiated heat entering the building.
Another way of controlling the effects of direct sun is to place verandahs on either side of the length of a building. This may be possible where there are only one-storeyed buildings. In multistoreyed buildings, this is uneconomical in space and costs.
Staircases, stairwells and rampways occupy a considerable part of space in each multistoreyed building. These should be positioned at the ends of the blocks of buildings.
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Artificial Ventilation:
Where air-conditioning is considered necessary, the design of the building will have to be as compact as possible.
Air-conditioning is the process of treating air to control all or some selected parameters viz. temperature, humidity, pressure, air movement pattern, air velocity and air cleanliness.
The cost of air-conditioning has direct relationship with the volume of the building. Therefore, the aim should be to restrict air-conditioning to the minimum and only where inescapable.
This is achieved by resorting to keeping the volume of the buildings low by low ceilings and restricting the size of the rooms to the absolute minimum.
However, certain areas of the hospital should always need air- conditioning. These are the operation theatre, labour room, postoperative recovery ward, premature nursery and accident and emergency department/ward and ICU.
Air-conditioning and artificial ventilation systems normally installed in offices, hostels and residential buildings are not suitable for hospitals.
Air hygiene, which is not at all considered in other buildings, is the most important factor to be considered in hospitals, and particular attention must be paid to it.
The basic principle to be adhered to is that the contaminated air from one part of the hospital is not transmitted to another. The decision should be taken at an early stage as the whole design of the buildings is affected by this decision.
Windows regulate the amount of light that enters a building. Very large areas of glass can result in overheating of the building in summer. It also produces severe discomfort from glare.
The patients lying in bed should not be exposed to too large an area of sky in direct view through the windows. It may be necessary to plan for shadowing devices to cut off the view of the sky from wards.
One of the ironies of planning hospitals in India is that when natural light abounds in the tropics, there is a tendency to provide for abundent artificial lighting. The effort should be to utilise natural light to the maximum and to consider the building design to cut power costs.