BUILDING SCIENCE 1 TOPIC TR 0 PICAL UPLAND

BUILDING SCIENCE- 1 TOPIC- TR 0 PICAL UPLAND CLIMATE Design for tropical upland zones 1 -Settlement Planning a) Topographical location of settlements b)Urban forms and external space 2 - Building design Building components a) Orientation of buildings a) Openings and windows b)Shape and volume c)Type and form of buildings b) Roofs c)Shading devices d)Immediate external space d)Natural ventilation e)Passive heating

ABOUT CLIMATE CONDITIONS The temperate and upland climate is characterized by three seasons. A hot and dry season, usually the longest period, is followed by a wet and warm season, the monsoon period. In the third season, the winter time, depending on the altitude, temperatures can drop far below the comfort level, especially at night, whereas daytime temperatures are moderate and the solar radiation intense

The main points: • Keep a balance between conflicting requirements. • Seek solar radiation gain in winter and provide shading in summer • Provide wind protection in winter and proper ventilation in summer • Construct “good-natured” houses, with moderate heat storage capacity. • Use medium sized windows 1 -Settlement Planning The main points • Topography, south sloping preferred. • Orientation, so as to benefit from the winter sun. • Protection from winter winds. • Form, semi-compact. • Hazards, floods, landslides and falling rocks must be considered

a) Topographical location of settlements Especially in areas of intensive land use buildings should be located on south slopes, where the sun exposure is adequate. Depressions should be avoided because cold air accumulates there. Above the bottom of the valley the microclimate is more favourable. Houses should be located behind a wind shield, but be assured of exposure to the sun. This shield can be formed by existing or newly planted vegetation, by other structures or by topography.

b)Urban forms and external space This pattern should be of a semi-compact type. The plot dimensions should allow the positioning of a building with its wider side facing south and sufficient distance from the neighbouring buildings. Provision for row buildings along the east-west axis may also be favoured. Public external space design The outdoor space - as in all warm regions should be actively used. It should be planned to provide a well-balanced mix of open, sunny areas for the cold season and shaded, wellventilated areas for the warm period. 2 - Building design The main points • Orientation and room placement should be south facing. • Form depends on precipitation pattern. • Shade in summer and heat gain in winter is necessary. • Ventilation must be controllable.

Sun orientation The orientation of the building greatly influences the solar heat gain; it should thus be carefully considered. Normally, buildings should have an elongated shape along the east-west axis. The southern front can easily be designed for proper utilization of the winter sun and for protection against the summer sun. Windows on the eastern side receive substantial heat during the morning, which may be highly appreciated in winter time. Usually, larger windows on the west side are to be avoided, as the solar heat gain through these would coincide with the highest air temperatures. Wind orientation Buildings should be arranged so that they benefit from summer winds because this season is usually humid and a proper crossventilation is required for cooling and hygienic reasons Shelter should be provided from the winter winds.

b)Shape and volume Buildings may be large and grouped close together. Row houses or adjoining buildings have the advantage of reduced heat loss. Courtyard buildings with proper wind protection are a suitable solution. The houses of Marpha, a village in the mountains of northern Nepal with a dry, cold and extremely windy climate, represent a good example c)Type and form of buildings moderately compact internal room arrangement is of benefit for most of the year. Courtyard buildings are suitable, terraced buildings facing south may also be appropriate. In cooler areas, exposure of the main rooms to the winter sun is essential, whereas in warmer areas these rooms can also be placed north facing.

D)Immediate external space The outdoor space should also be designed as a compromise with ventilation and shade in summer, and wind protection and solar radiation gain in winter. The vegetation should be planned accordingly, to provide partly sunny and partly shaded spaces. Deciduous trees are an excellent medium with which to achieve this goal. Building componentsc) Openings and windows Double glazed leaves could be an advantage For the construction of windows and doors it is very important to use wellseasoned timber. Only then will panels remain straight and airtight Windows should be equipped with tightly closing glazed panels, which provide protection against heat loss during the cold season and also against flow of heat and dusty air during the dry and hot season.

d) Roofs Waterproofing The roof should protect the building from precipitation and therefore be carefully waterproofed. Thermal insulation The roof should provide protection against heat gain in summer and heat loss in winter. The roof should, therefore, have thermal insulation properties. In upland regions the construction should be airtight, the joints between construction elements requiring special care. e)Shading devices Walls do not need extra shading devices in this type of climate, provided they possess reasonably good insulation and reflective properties Solar angle consideration

Vegetation Deciduous trees are suitable for shading purposes. Such shading trees are best located on the east and west side of a building. Vegetation which is too dense and too close to the building should be avoided because of dampness effect. Deciduous trees provide access to winter sun but protect against summer sun A green cover on outer walls and roof has many advantages: • It protects the walls against driving rain. • Glare is eliminated In winter time, a dense green coverage can be a disadvantage because desired the solar heat gain may be reduced. By using deciduous plants this effect can be avoided.

d)Natural ventilation Protection against cold winter winds should be balanced by proper ventilation during hot and humid periods. Therefore, regulated air movement is a primary requirement. This can be achieved by well planned openings The way plants can be arranged to achieve the desired ventilation

E)Passive heating The concept designed by Socrates The basic idea was formulated by Socrates, who designed a concept with three elements: • Capturing as much winter sun as possible • Keeping out solar radiation in summer time • Using a thermal buffer zone towards the north 1. Summer sun 2. Winter sun 3. Covered verandah 4. Living room 5. Storeroom as thermal buffer zone 6. Insulated wall towards the north Passive solar gain Using direct solar energy in a building requires that the majority of windows are located on the south elevation. The sun’s rays enter the building through the windows and strike the floors, walls and objects in the rooms, where the greatest part is absorbed and converted into heat.

The floor as collector and heat storage mass Internal walls as collector and heat storage mass The ceiling as collector and heat storage mass