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A window to well-being

9 Comments
Author(s): Disha Singh
Feb 28, 2013 | From the print edition

Natural ventilation is a good way to perk up life

Chhajjas, which reduce direct heat from the sun, are used aesthetically in Jaisalmer“During childhood, the worst punishment my parents gave me was spending a few minutes in the windowless storeroom of our house in Allahabad. In Delhi, it has become a way of life,” says Ritu Priya, a Delhi University student. Due to monetary reasons, she has to live in a matchbox-shaped accommodation in Delhi. “Over the years, the flat has governed my well-being,” says Priya who is unable to pinpoint the effect the compact flat has had on her.

Bhawna Yadav, a clinical psychologist in Mumbai, sheds light. “People working or living in dingy environment are more prone to depression and take longer to recover. Such an environment induces lethargy.” The Journal of Urban Health acknowledges that built environment has direct and indirect effects on mental health. It states poor quality housing increases psychological distress and insufficient daylight is associated with increased depressive symptoms. A WHO report says inadequate ventilation is associated with a higher risk of airborne diseases, including tuberculosis, as well as the accumulation of indoor pollutants and dampness, which are factors in the development of allergies and asthma.

No mental space

Psychological comfort is one of the neglected aspects of modern buildings. “Provision for adequate sunlight, fresh air and connection with nature can do wonders to the well-being of the occupants of any building, says Yadav. Natural ventilation and lighting are critical to design and functioning of a building, stresses Neha Aggarwal, an architect in Chandigarh. They affect not only the mental health but the overall health of a person.

Like lighting, ventilation can be achieved through mechanical or natural methods. Today much of the expenditure to make a building functional is on mechanical ventilation and artificial lighting. In fact, most of the popular trends in real estate, like central air conditioning and glass façade, are attributed to need for better ventilation and lighting requirements. “If means of natural ventilation and lighting are incorporated in a building, they will help bring down the project cost considerably,” says Anupama Kundu, an architect in Auroville, Tamil Nadu.

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Traditional building systems like courtyards, verandahs, jaalis (lattice work) and jharokhas (windows) not only help buildings breath, but also ensure psychological comfort. But these features are progressively disappearing from the urban built environment. Even the chhajja (a horizontal slab above windows and doors), once a common building element, has become an endangered species of architectural typology. “People want rooms that provide enough space for breeze and the sun, but they are a rarity. And houses that have such spaces fetch premium prices,” adds Priya.

Traditionally, the best

Chhajja is the simplest of weather control devices for buildings. It projects over a window, primarily to cut down the direct heat from the sun. It doubles up as a rain protector and directs the wind inside the room.

Creatively designed chhajjas can even help increase the penetration of sunlight into the interiors. They even provide space for bird nesting. “To suit the Indian weather conditions, the minimum depth of the chhajja should be 0.6 metres,” says C L Razdan, an architect in Jammu.

The most common way of inducing natural ventilation in a building is catching the wind. It relies on the principle that air flows from high pressure to low pressure areas. Ideally, the inlet openings should be on the windward side (high pressure) of the building and the outlet openings on the leeward side (low pressure). When the wind hits the inlet openings, the low pressure on the opposite side forces the air to flow through the building’s interior to the outlet openings. One can also use a courtyard for ventilation and lighting. When air becomes hot, it becomes lighter and rises and cold air rushes to take its place (called stack effect). That’s how a courtyard provides ventilation.

Even vastushastra talks about the various methods of natural ventilation and explains ways to incorporate them in a house or a building. “According to vastu, ventilation is responsible for the flow of energy through a building,” says Aggarwal. But a building with natural ventilation is challenging to design as the wind direction and velocity varies from time to time. The National Building Code 2005 recommends the orientation of a building need not be perpendicular to the prevailing wind. It can be oriented between 0° to 30° without losing out on the benefits of the breeze. However, factors like sun’s movement and the surrounding buildings should be kept in mind.

“In today’s fast-paced life, the majority of the people opt for mechanical means of ventilation. People rarely understand the importance of using traditional methods,” says Aggarwal.

Inputs by Avikal Somvanshi

AddThis

We are unable to appreciate our valued system because those who governed free India,were mostly educated in western oriented schools and colleges and most of the times where people ridiculed the Indian things. Now that science is proving that Oxygen,water,minerals are necessary for the health, there is beeline for water purifiers ,various health drinks supposedly fortified with vitamins and minerals. However, the need for oxygen is still not understood by majority of the people and most of the architects who are responsible for making ill designed unhealthy buildings.Your article serves useful purpose if people and more architects follow it.They do not have to reinvent wheel,it is already there in old buildings.
Copy it if you so desire.Arun B.Agarwal

21 February 2013
Posted by
Arun B.Agarwal

It is sad that now a few architects are reminded of old construction practices after they have gradually done away with all ventilators,cross- ventilations,courtyards,Jharokhas, high ceilings,use of lime etc.I hope the feelings of these few will spread and people will not be denied enough fresh air for the sake of Rupees here and there.Arun B.Agarwal

21 February 2013
Posted by
Arun B.Agarwal

Dear Arun
Thank you for your appreciation. I am in agreement with what you have said in your comments.

In India we have a tendency to blindly copy the trends of the west even at the cost of our own traditional design principles. These passive design strategies, such as harnessing natural ventilation, have been perfected over centuries to suit our climate but are now being ignored.

It is our endeavor through these articles to increase awareness among the public with regard to these simple but necessary aspects of building design.

22 February 2013


Posted by
Disha Singh

Vaasthusasthra is basically the science of harnessing the 5 elements of nature-the panchabhootas and create living spaces that are in harmony with nature.Each region has its own vaasthusashtrsa depending upon the longitude and latitude.The indian vasthusasthra speaks of two sutras, the karnasuthra and the yamasuthra,dwelling spaces have to be constructed without blocking these two suthras, and the idea behind this is to allow free flow of outside fresh air inside and remove the inside stale air, we engineers call this process as natural draft scavenging.Even the old arab dwelling spaces made use of these principles of natural draft.You can come across wind towers above old arab buildings; these towers allowed outside air to pass through damp clothes and provide cool air inside, when the temperatures outside are scorching.Unfortunately, we have discarded all this and adopted artificial cooling and ventilation methods which are highly energy intensive.

22 February 2013
Posted by
Prof.P.P.Premachandran

Dear Prof. Premachandran

I concur with the what you have stated in your comment. The worrying aspect is that India's growing dependency on mechanical cooling and ventilation is resulting in a sharp increase in electricity consumption resulting in a major shortfall in our already insufficient electric supply.

Vaastushastra relies on harnessing natural elements to suit the climate, rather than creating an artificial and hi-tech internal environment which is energy intensive.

Considering these aspects, it is imperative that professionals like architects, engineers and the common man must understand that harnessing natural ventilation in buildings will help reduce the electricity consumed in keeping them cool.

22 February 2013


Posted by
Disha Singh

Dear Disha Singh,
Your article on natural ventilation was a well timed one. It is now a known fact that almost all the states in the country are reeling under severe power shortages, and a major consumer of electricity is air conditioning. Here in kerala we had a rich tradition of embeded vaasthusasthra, and so we had houses that did not even require fans to be switched on even during peak summer time.But the present trend is to design buildings in which even fresh air has to be pumped from outside, at the same time take out stale air using heavy duty exhaust fans. It seems that our policy-makers have a totally distorted idea regarding development, In these parts it goes like this--fill up farmland, construct air conditioned shopping centres/malls, build wide roads. all this with scant regard to natural water flow natural air flow, flora and fauna, and topography of the area.

23 February 2013
Posted by
Prof.P.P.Premachandran

Dear Prof. Premachandran
In my opinion this problem has arisen as nowadays there is a trend for replicating or getting inspired by buildings in the west. It is common sense that these buildings would not be suitable for the Indian climate. Most of these buildings are designed to be completely enclosed, air tight and have a large floor area width.
Traditionally Indian buildings have always been open to the outdoors with the help of courtyards, chajjas, jharokhas, terraces, deep verandahs, ventilated roofs, ample cross ventilation, permeable building materials etc. But these so called "modern" buildings have scant regard for any of the traditional principles. So it comes as no surprise that this present vocabulary of buildings requires a tremendous amount of energy to function.
Through such articles (like the present one), we at CSE hope to shed some light and make people aware of the importance of such simple but vital aspects involved in a building.

25 February 2013


Posted by
Disha Singh

Excellent article.

Nothing to beat natural ventilation. After the Divi Taluq devastating Cyclone in Andhra Pradesh,shelter houses were constructed and given free to the displaced. They have poor ventilation. Many did not occupy these box type houses. On the other hand the workers used to sleep in open and under the trees in the afternoon. Man prefers to live in harmony with nature.
Dr.A.Jagadeesh Nellore(AP),India

8 July 2013
Posted by
Dr.A.Jagadeesh

Hi,

Do you know of any architects or designers who can help me build a environment friendly home? But I cannot really afford anything very costly...

4 March 2014
Posted by
Vineela

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