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For many Indian women today, the sari is more an outfit for rare, dressy occasions than utilitarian daily wear. Better the pre-stitched convenience of trousers or salwar kameezes than the fumbling that comes with six-yards of freeform fabric. Yet, a new study by a Riyadh-based researcher of Indian origin turns the idea on its head, showing that the Indian sari scores over western wear on at least one aspect of convenience – insulation. Much like a thermos flask, the sari has the ability to keep its wearer warm or cool, depending on the weather around her. It’s all in the pallu, the study shows. Depending on whether you pleat the pallu or drape it across your shoulders, you can alternate between the warmth of a sweater and trousers or the breeziness of a summer skirt and blouse.

This finding was reported last month in the journal Architectural Science Review by a group of researchers from South Korea’s LG Electronics and University of California, Berkeley. Lead author Madhavi Indraganti, who is currently a professor at Prince Sultan University in Riyadh, studies thermal comfort – the perception of comfort which people experience when the temperature, their clothing and the air speed around them is just right. Indraganti’s work involves speaking to occupants of residential and commercial buildings to understand what contributes to their thermal comfort and then creating mathematical models to help building designers pick the most appropriate architecture for a climate. As Indraganti tells me in an interview on the phone, “Thermal comfort is the primordial reason behind human existence. If it wasn’t for thermal comfort, we wouldn’t be alive.”

We humans are fair-weather people: there is a very narrow band of temperatures in which we can survive. So we widen this band by wearing (and taking off) clothes and building houses, thus allowing us to live in inhospitable regions such as Antarctica and the Sahara. Even so, we don’t always manage to make conditions perfect for ourselves, and this, predictably, hurts our productivity. In a 2006 analysis of 26 previous studies on the relationship between workplace temperature and productivity, Finnish researchers found that the productivity rose with each degree Celsius upto the 20-23 degree band, peaked at 21.6 degrees, and then began dropping past 24 degrees.

Indraganti and her team have also been looking for data on the optimum temperature for productivity in India, but not much is available. India’s National Building code, a compulsory code of health and safety standards for buildings, borrows over two-decade old guidelines from ASHRAE, an international society that sets standards for building design. Apart from being obsolete, the ASHRAE 1992 standards borrowed by India also rely on studies conducted in western countries. This is a problem, because India has very diverse and unique climatic zones, with both Himalayan and desert conditions. Such diversity in climatic zones means that the temperature at which people experience thermal comfort varies from place to place in India, something not captured in the Indian building code.

The other problem is that ASHRAE 1992 standards assume that building occupants wear western clothes – business suits, skirts or trousers for women – something that doesn’t hold for the majority of Indian offices. “If you really follow these standards, it will be very detrimental to our environment given the power shortage we have,” says Indraganti. Designing buildings for the wrong temperature standards means they will be too cold or too hot, requiring enormous quantities of power to correct.

These are the problems that got Indraganti interested in studying Indian buildings and their occupants more closely. And one of the things she has to put a number on for this is the insulation potential of the Indian sari.

For her study, Indraganti and team used thermal manikins – physically indistinguishable from the mannequins displayed in clothing store windows – but with a complicated apparatus inside that helps them generate heat and dissipate it the way human bodies do. They then placed these manikins in a climate chamber, designed to simulate a variety of environments, at the University of California, Berkley.

Next, they draped the manikin in nine sari ensembles. Seven of these were summer ensembles, put together using a lightweight yellow silk sari of a south Indian design called Kalakshetra, and a heavier green handloom poly-cotton sari from the Gadag region of Karnataka. Two were winter ensembles, which threw in an acrylic shawl on top of the green Gadag saree. In some ensembles, Indraganti and team pleated the pallu, while in others, they left it loose. In some they draped it over the shoulder, while in others they left it hanging behind the back. All the ensembles included a petticoat, or a long skirt worn under the sari, a blouse and undergarments. The manikin’s temperature was set at 34°C, approximately the temperature of our skin. Finally, the team measured how good the ensembles were at preventing heat loss from the body.

What they found was that depending on how the pallu was draped, the sari could offer a variety of insulation levels. Just covering the arms fully with the pallu increased insulation by 47 percent.  On the other hand, a pleated pallu sari, with a low clothing insulation value (measured in clo units) of 0.65 clo, was as airy as western summer ensembles such as formal turtleneck blouses and skirts. “The sari is a very dynamic attire,” says Indraganti.

Proponents of the sari have been saying this for years. Rta Kapur Chishti, a textile scholar and the founder of the Delhi-based The Sari School, says each climatic zone in India has its own interpretation of the sari, to help the wearer adapt to the weather. She documents around 108 of these from 15 states in her book Saris of India: Tradition and Beyond. This kind of adaptability is possible with the sari because, Rta says, “It is not a structured garment. You can make of it what you want – a pair of pants, a pair of pantaloons, a short dress, a long dress, a gown. You can reinvent it – it is not a kimono.”

How is it that the sari, with its multi-layered skirt, is no more insulating than a single-layer western skirt, as Indraganti’s study shows? The sari pulls off this trick by its clever design, explains Indraganti. First, the sari skirt is conical, with the tight pleats around the waist flaring into a larger circle near the feet. This allows small currents of air to move up and down the legs, swished about by the motion of the pleats.  Then there is the exposed midriff, which keeps the skin cooler. Women who engage in physically intense work can go one step further and lift their hemlines by pulling their pleats up and tucking them into their waistbands. Just this act brings down the sari’s insulation value by another 40 percent, Indraganti found in another study.

Kalev Kuklane, a thermal environment researcher at Sweden’s Lund University who has also conducted studies on the sari, says the sari’s versatility is a definite advantage amongst workers who experience different temperatures within the course of the day. For those who travel between a hot and cold environment or those who get periods of rest between periods of high activity, an adjustable garment like the sari makes logistics easier. An alternative would be to carry along an extra piece of

clothing, like a jacket, but that could be inconvenient.

Indraganti’s study shows that “we have a lot to learn from the traditional clothing,” adds Kuklane. From the thawb worn by Arab men, which shields them from solar radiation during the day and warms them at night, to the wide-brimmed hats worn by farmers in Latin America, traditional clothes pull off many tricks without much technology.

That’s why Indraganti rues that some Indian offices impose absurd dress codes that don’t allow for the adaptation possible in traditional attires. One example is leather shoes and full-sleeved shirts for men. During a thermal comfort survey she conducted in Hyderabad, she noticed that while all men stuck to the dress code when they walked into the office in the morning, they would roll up their sleeves and kick off their shoes by the afternoon. “If I am allowed to wear something more conducive to my cultural climate, I would tolerate the weather better,” she argues.  Perhaps these offices would do well to switch to the south Indian lungi – another promising garment that Indraganti is carrying out insulation studies on.

Priyanka Pulla is freelance science journalist based in Bangalore.

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