how warm and humid climate help in building construction,what are the advantages and dis advantages

1. CLIMATOLOGY

2. hot and humid climate
In hot and humid climatic regions, high
temperatures are accompained by very high
humidity levels leading to immense discomfort.
Cross ventilation is very essential here. Adequate
shading measures are also necessary to protect the
building from direct solar radiation.

3. The main design objectives should be
(A) Resisting heat gain:
Measures that are convenient to gain unwanted heat gain are:
(a)Decreasing surface area of the building exposed to the outside.
(b)Using materials that take a longer time to heat.
(c)Providing buffer spaces between the outside and the inside.
(d)Increase the shade of the building in general.
(e)Using materials that reflect heat.

4. (B) Promoting heat loss:
To promote heat lost it is essential to ensure:
(a) Appliances used are well ventilated.
(b) Proper ventilation occurs throughout the day.
(c) humidity levels are reduced as much as possible.

5. General recommendations for building design in warm and humid
climate
(1) Site:
(a)Landform:
For flat sites, design consideration for the landform is
immaterial.
In case of slopes and depressions, the building should be located
on the wind ward side or crests to take advantage of cool
breezes.
MAXIMUM AIR SPEED ON THE CREST

6. (b) Waterbodies:
Waterbodies are not essential as they would tend to further
increase the humidity.
(c) Street width and orientation:
Major streets should be oriented parallel to or within 30 of the
prevailing wind direction during summer months to encourage
ventilation in warm and humid regions. A north-south direction
is ideal from the point of view of blocking solar radiation. The
width of the streets should be such that the intense solar
radiation during late mornings and early afternoon is avoided
during the summers.

7. (C) Open spaces and built form:
Buildings should be spread out with large open spaces in between
for unrestricted air movement.
In cities, buildings on stilts can promote ventilation and cause
cooling at the ground level.
BUILDING SPACING SUCH THAT AIR FLOW IS PROMOTED

8. (2) Orientation and planform:
As long as the temperatures are very high, free plans and can be
evolved as long as the house is under protective shade. An
unobstructed air path through the interiors is important to ensure
proper ventilation. The buildings could be long and narrow to
allow cross ventilation. For example, a singly loaded corridor
plan (i.e. one with rooms on one side only) is preferable over a
doubly loaded one.
ELONGATED PLANS FOR MAXIMUM CROSS VENTILATION

9. (a)Heat and moisture producing areas like toilets and kitchens
must be ventilated and separated from the rest of the
structure.
VENTILATE KITCHENS AND BATHS TO EXHAUST HOT AIR

10. (b) Semi open spaces such as balconies, verandahs and
porches can be used advantageously for day time activities
as well as give protection from rainfall. In buildings a
central courtyard can be provided with vents at higher
levels to draw away the rising hot air.
WINDOWS AT HIGH LEVEL TO VENT HOT AIR

11. HIGH PITCHED ROOFS WITH LOUVERS FOR VENTILATION
(3) Building envelope:
(a)Roof:
In addition to providing shelter from rain and heat, the form of the
roof should be planned to promote airflow. Vents at the rooftop
effectively induce ventilation and draw hot air out.

12. Insulation does not provide any additional benefits
for a normal RCC roof in a non-conditioned building.
However, very thin roofs having low thermal mass,
such as AC sheet roofing, require insulation as they
tend to rapidly radiate heat into the interiors during
day time. A double roof with ventilated space in
between can also be used to promote air flow. The
space in between can also act as a heat buffer.

13. (b) Walls:
The walls must also be designed to promote air flow so
as to counter the prevalent humidity. Baffle walls,both
inside and outside the building can help to divert the
flow of wind inside.
BAFFLE WALLS HELP TO DIVERT AIR FLOW

14. They should be protected from the heavy rainfall prevalent in
such areas. If adequately sheltered, exposed brick walls and
mud plastered wall work very well by absorbing the humidity
and helping the building to breathe.

15. (c) Fenestration:
Cross ventilation is of outmost importance in warm and
humid climatic regions. All doors and windows should
preferably kept open for maximum ventilation for most of the
year. These must be venetian blinds or louvers to shelter the
rooms from the sun and rain, as well as for the control as air
movement. Openings of a comparatively smaller size can be
placed on the windward side, while the corresponding
openings on the leeward side should be bigger for facilitating
a plume effect for natural ventilation.

16. The openings should be shaded by external overhangs. Outlets at
higher levels serve to vent hot air.
OUTLET LARGER THAN INLET INLET AT LOWER LEVEL AND OUTLET AT HIGHER LEVEL

17. Examples illustrating how the air movement within a room can
be better distributed.
DISTRIBUTE AIR THROUGHOUT THE ROOM

18. (d) Colour and Texture:
The walls should be pasted with light pastel shades or white
washed while the surface of the roof can be of broken glazed
tile (china mosaic flooring) to reflect the sunlight back to the
environment, and hence reduce heat gain of the building. The
use of appropriate colours and surface finishes is a cheap and
very effective technique to lower indoor temperatures. The
surface finished should be protected from/resistant to the
effects of moisture.

19. Remarks:
Ceiling fans are effective in reducing the level of
discomfort in this type of climate. Desiccant cooling
techniques can also be employed as they reduce the
humidity level. Careful water proofing and drainage
of water are essential considerations of building
design due to heavy rainfall. In case of air conditioned
buildings, dehumidification plays a significant role in
the design of the plant.