1. DBN163 – BUILDING SCIENCE (I)
Site Climate / Macro-Micro ClimateSite Climate / Macro-Micro Climate
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BALKHIZ ISMAILBALKHIZ ISMAIL
JAB. BANGUNAN, FSPU, UiTM SARAWAKJAB. BANGUNAN, FSPU, UiTM SARAWAK

2. General Introduction
 In the built environment we are generally
concerned with local climatic systems in particular:
1. Macro-climate the climate of a larger area such as a
region or a country
2. Micro-climate the variations in localised climate
around a building
 The macro and micro climate has a very important
effect on both the energy performance and
environmental performance of buildings, both in
the heating season and in summer.
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3. Macro-Micro Climate
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4. Macro Climate
 The macro climate around a building cannot be
affected by any design changes, however the
building design can be developed with a
knowledge of the macro climate in which the
building is located.
 The knowledge data gives a general impression of
the climate at the site of a building and the building
design can be planned accordingly.
 However the building itself and surrounding
geography will affect the local climate
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5. Macro Climate
 General climatic data give an idea of the local
climatic severity:
 Seasonal accumulated temperature difference
(degree day) - a measure of the outside air temperature,
though do not account for available solar
 Typical wind speeds and direction
 Annual totals of Global Horizontal Solar Radiation
 The Driving Rain Index (DRI) - the amount of moisture
contained in exposed surfaces and will affect thermal
conductivity of external surfaces.
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6. Site Climate
 Assumption of climate for a large project that
covering extensive area.
 On small sites, where there is less scope for
variations in siting and orientation, this exercise
will be more limited, but some consideration of
local climatic patterns will always be justified.
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7. Micro Climate
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8. Micro Climate
 A local atmospheric where the climate differs
from the surrounding area.
 The site of a building may have a many micro
climates caused by the presence of hills valleys,
slopes, streams and other buildings.
 The term may refer to areas as small as a few
square feet or as large as many square miles.
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9. Climate Deviation
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10. Factors Influencing Micro Climate
1. Solar Access
 Minimising solar overheating in summer
while maximising solar access during the winter.
 Buildings with a heating requirement should be orientated
north south with maximum glazing on the south face.
 Trees offer an excellent means of site shading
 The colour of surrounding surfaces will have an effect on
the solar radiation available to the building.
 Grass planted outside a building will reduce the ground
reflected solar.
 Use of courtyards and water can also moderate the
effects of high temperatures on summer. 10

11. Factors Influencing Micro Climate
2. Wind Control
 Avoidance of funnel-like gaps between buildings
 Avoidance of flat roofed buildings and cubical forms
 Avoid abrupt changes in building heights
 Orientate long axis of the building parallel to the direction of
the wind
 Use podium to limit down draught at ground level
 Groups of buildings can be arranged inirregular patterns to
avoid wind tunneling.
 Coniferous trees and fencing and other landscape features
(mounds of earth and hedges) - reduce the impact of wind
and driving rain on the building structure. 11

12. Climate Deviation
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Factors which may cause local deviation are:-

13. Urban Climate
The factors causing deviations of urban climate:
1.Changed surface qualities (pavements and
buildings) – increased absorbance of solar radiation;
reduced evaporation
2.Buildings – casting a shadow and acting as barriers
to winds, channeling the wind by increase in velocity
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14. Urban Climate
3. Energy seepage – through wall and ventilation of
heated buildings
4. Atmospheric pollution – waste products, smoke
from motorcars, fumes and vapors
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15. Level of Deviation
1. Air temperature – a city will have a higher
temperature than the surrounding countryside –
11°C has been reported
2. Relative humidity – reduced by 5-10% - quick
run-off rainwater, absence of vegetation, higher
temperature
3. Wind velocity – reduced to less than half of that in
the adjoining open country
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16. REFLECTION
What are the differences between
MACRO & MICRO CLIMATE?
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