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ARCHITECTURE FOR HOT AND HUMID CLIMATE…

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HOT AND HUMID CLIMATE <ul><li>In hot and humid climatic regions, high temperatures are accompanied by very high humidity levels leading to immense discomfort. Cross ventilation is hence very essential here. Adequate shading measures are also necessary to protect the building from direct solar radiation. </li></ul>

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WHY THE CLIMATE OF PLACE LIKE MUMBAI IS HOT AND HUMID? <ul><li>Places that are close to sea or oceans have a humid climate as there is large amount of water vapour in the air. Actually what happens, land and water don't get heated at the same rate.Land gets heated faster so it radiates the energy , that heats the air above the land, as a result of which air above the land gets heated faster than air above the water bodies. Now hot air is lighter so it moves up and the surrounding air above the seas rushes to take its place which has lots of water vapour in it. This is the reason for humidity . </li></ul>

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<ul><li>One more reason for that is the fact that Mumbai is near the Equator, where the light from the sun hit's most directly.The Earth is tilted, so hence the Equator is right in front of the sun, & hence the heat from the sun is best </li></ul><ul><li>received there. </li></ul>

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Geography of Mumbai : <ul><li>The exact geographical location of Mumbai lies in the west coast of the state of Maharashtra facing the Arabian Sea. It is an interesting fact that one fourth of the city of Mumbai lies below the sea level. Mumbai is spread across a total area of 440 sq. kms. There are two ridges of flow hills that covers the city on the East side and west side that forms a sort of barrier from the vast and open expanses of the Arabian Sea. The highest point of Mumbai is the Malabar hills having a height of 180 feets above the sea level. </li></ul>

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Climate of Mumbai: <ul><li>The weather of Mumbai remains hot and humid through out the year. This is mainly because of the cities proximity to the Arabian Sea. However the weather turns out top be pleasant during the months of November to March the winter in Mumbai. During this period the Mumbai sky remain clear without clouds and the temperature also cools down. The temperature starts rising from the months of March and it continues until mid June when the Monsoon breaks out. The monsoon season in Mumbai follows till September and it brings a relief from the heat and the humidity. That is why the best time to visit Mumbai is between the months of October and March. The temperature in the summer months usually varies from 35 to 23 degree Celsius. On the other has winter brings a respite from the sweltering heat as the temperature goes down from 29 to 19 degree Celsius. </li></ul>

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Climate of Mumbai

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The main design objectives should be: <ul><li>( A) Resisting heat gain </li></ul><ul><li>Measures that are convenient to resist unwanted heat gain are: </li></ul><ul><li>(a) Decreasing surface area of the building exposed to the outside. </li></ul><ul><li>(b) Using materials that take a longer time to heat up. </li></ul><ul><li>(c) Providing buffer spaces between the outside and the inside. </li></ul><ul><li>(d) Increasing shading of the building in general. </li></ul><ul><li>(e) Using materials that reflect heat. </li></ul>

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

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General recommendations for building design in warm and humid climate are: <ul><li>Site </li></ul><ul><li>(a) Landform </li></ul><ul><li>For flat sites, design considerations for the landform is immaterial. </li></ul><ul><li>In case of slopes and depressions, the building should be located on the windward side or crest to take advantage of cool breezes. </li></ul>

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<ul><li>b) Waterbodies Water bodies are not essential as they would tend to furtherincrease the humidity. </li></ul><ul><li>(c) Street width and orientation </li></ul><ul><li>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 morning and early afternoon is avoided during the summers . </li></ul>

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<ul><li>(c) Open spaces and built form </li></ul><ul><li>Buildings should be spread out with large open spaces in between for unrestricted air movement. </li></ul><ul><li>In cities, buildings on stilts can promote ventilation and cause cooling at the ground level . </li></ul>

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(2) Orientation and Planform <ul><li>As temperatures are not very high, free plans can be evolved as </li></ul><ul><li>long as the house is under protective shade.An unobstructed air </li></ul><ul><li>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. </li></ul>

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<ul><li>Heat and moisture producing areas like toilets and kitchens must be ventilated and separated from the rest of the structure. </li></ul>

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<ul><li>Semiopen spaces such as balconies, verandahs and porches can be used advantageously for daytime activities as well as give protection from rainfall.In multistoreyed buildings a central courtyard can be provided with vents at higher levels to draw away the rising hot air. </li></ul>

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(3) Building Envelope <ul><li>(a) Roof </li></ul><ul><li>In addition to providing shelter from rain and heat, the form of the roof should be planned to promote air flow.Vents at the rooftop effectively induce ventilation and draw hot air out. </li></ul>

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<ul><li>Insulation does not provide any additional benefit 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 daytime.A double roof with a ventilated space in between can also be used to promote air flow. The space in between can also act as a heat buffer. </li></ul>

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<ul><li>(b) Walls : </li></ul><ul><li>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. </li></ul>

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

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<ul><li>(c) Fenestration </li></ul><ul><li>Cross-ventilation is of utmost importance in warm and humid climatic regions.All doors and windows should preferably be kept open for maximum ventilation for most of the year.These must be provided with venetian blinds or louvers to shelter the rooms from the sun and rain, as well as for the control of 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. </li></ul>

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<ul><li>The openings should be shaded by </li></ul><ul><li>external overhangs.Outlets at higher </li></ul><ul><li>levels serve to vent hot air. </li></ul>

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Examples illustrating how the air movement within a room can be better distributed

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<ul><li>(d) Colour and texture </li></ul><ul><li>The walls should be painted with light pastel shades or whitewashed, 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 finish should be protected from/ resistant to the effects of moisture. </li></ul>

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<ul><li>Remarks </li></ul><ul><li>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.n case of air conditioned buildings, dehumidification plays a significant role in the design of the plant. </li></ul>

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<ul><li>ASMITA RAWOOL </li></ul><ul><li>RIA SAURAV </li></ul><ul><li>NITIKSHA PATEL </li></ul><ul><li>ANJALI SINGH </li></ul><ul><li>RAGINI SINGH </li></ul><ul><li>SHRUTI AIL </li></ul>