The Sena Kallayan Bhaban in Motijheel was built sometime in the 1980s.
"The curtain wall was made with big dark glasses, which provided no transparency and lessened glare," remembers veteran architect Ehsan Khan. "This might seem like a basic structure now, but I remember at that time, it was a bold statement regarding glass technology."
Fast forward a couple of decades, the Bashundhara city complex in the capital's Panthapath area and the Grameenphone centre at Bashundhara, inaugurated in 2004 and 2010 respectively, were two of the most prominent buildings in Dhaka which had a full glass exterior. Both were designed by veteran architect Mustapha Khalid Palash.
The Bashundhara shopping complex was actually more advanced because a circular tower was created using segmented straight glass sheets - which are tempered, and hence safer and sturdier. Meaning under huge pressure, this glass will break into sugar-like crystals instead of large sharp pieces, which is safer for the people around.
Ever since, Dhaka city has seen a surge in glass skyscrapers, especially the corporate buildings located in Tejgaon, Banani, and Gulshan.
Over the last couple of years, a number of commercial projects - completed and under-construction - have begun incorporating liberal use of glass in both their interior and exterior architecture.
The Beximco Learning and Development Centre in Tongi, designed by architect Rashed H. Chowdhury, uses glass to partition office spaces. This design choice was also echoed by SthaNiK Architectural Consultants for 'the FBS library' in the Dhaka university's business faculty.
Another notable, yet unfinished project, by Cubeinside Design Ltd and Dcon Design Studio is the renovated complex of Sufiya Kamal public library in Shahbag, which is going to have a glass plaza that will serve as an e-library.
Why is glass becoming more and more popular? According to Ehsan Khan, because of two factors - economic and technological development. People can now afford quality glass panels, which adds to the glamour of this metropolis. And better quality technology is available in the market, making glass safer and sturdier.
Furthermore, in a tropical country like Bangladesh with an ample amount of direct sunlight, architects prefer double-glazed low-e glass (short for low emissivity).
"It is not just a design element anymore, now glass sheets are used with functionality in mind," said Ehsan Khan, who designed the 40-storied 'Shanta Pinnacle' which is set to be the tallest edifice in the country.
Ehsan said architects now prefer to use low-e double glazed glass, unitised system-built glass panels, which help maintain the interior temperature.
"Glass has the ability to open up a space, unlike solid concrete walls. And this is something the indoor desk-based corporate world needs- an ample amount of light to get the maximum output from the employees," he said.
In a 2009 journal titled, 'Daylight for energy savings and psycho-physiological well-being in sustainable built environments,' the author Sergio Altomonte emphasised on how natural daylight is important in a workplace.
According to the paper, daylight can positively influence the health of office personnel, improving efficiency, reducing unnecessary sick leaves and resulting in greater benefits for enhanced productivity.
If carefully designed, a daylight strategy can also bring tangible energy savings, as long as it minimises energy use for artificial lighting and prevents glare and other visual discomforts (such as contrast, adaptation problems and internal reflections).
"In Bangladesh, we have a humid, hot, and windy atmosphere," said architect Jubayer Shahadat, adding "that is why we see this glass façade trend in corporate areas, where a pleasantly cool temperature is necessary inside the office for maximum employee output, heat insulation is hence important."
But is glass compatible with the climate of Bangladesh?
Architect Mustafa Khalid Palash, designer of the Bashundhara Shopping Complex and GP centre, said, "We want the visible light to enter our space but not the temperature or the invisible but harmful ultraviolet and infrared ray. And glass allows that. But what it does is reflects the harmful rays, making the surrounding area warmer."
"It is not ideal for us to use too many glass structures because the glare from the glass can increase the temperature of these areas. So there is a certain balance we need to keep in mind," said architect Ehsan Khan.
Not just for the workplace
Apart from commercial buildings, glass facades and openings are used in residential buildings to highlight beautiful views.
The 3775 m² residential building 'The Statesman', designed by studio Morphogenesis, located in Dhaka's Gulshan area, has a large glass facade all over the north side. With sliding glass walls inside and aluminium screens on the outer shell, the building incorporates the contrast between clearly defined public spaces and private zones.
"It depends on the space you are creating - if it is a residential space, you need to ensure privacy, hence you will see enclosed zones with specific openings like windows and doors," explained Ehsan Khan, adding "but if it is a corporate space, you will want to ensure transparency for view, natural light and also for better visual connectivity among the employees. Either floor to floor or partial - glass facade ensures these features for an office."
Growing popularity as building material
Glass is now considered an intelligent building material. The manufacturing technology of curtain glass has developed such that the glass pieces are produced in industries following specific design and delivered to the construction site as prefabricated materials.
The worldwide use of glass has found its way into the list of popular building materials in Bangladesh.
"While the windows in the apartments use 5 to 5.5 mm mercury or reflective glasses, the commercial spaces use 10-12 mm glasses. The government projects use clear glasses. For partition, 10 mm tempered glasses are used," said Akhtarul Islam, Dhaka area manager of Nasir glass industries.
"For curtain walls, double glazed low-e glasses, which are mainly 10 mm and tempered, are sometimes used, but double glazed glasses are used more often. This glass allows an edifice to maintain the temperature, and you can use two coloured glasses. In between those two sheets of glasses, there is air or argon gas insulation."
As argon gas is denser than air, adding it to the glass unit in double-pane windows improves thermal insulation efficiency. Used in conjunction with a special low-e glass coating, argon gas windows bring the temperature of the window closer to room temperature.
The glass industry in the country is growing by 8-10% every year, with local companies meeting 90% of the domestic demand, recents reports say. The current size of the glass industry is around Tk1,500-2,000 crore.
The annual demand for glass is 25 crore square feet, and the annual production capacity of private and public glass manufacturers is 32 crore square feet.