A hushed silence takes over the vivacious ambience at a party when your cocktail glass slips and breaks with a loud clank.
Immediately, the fear that you might accidently step on a piece of sharp glass takes over and there is a momentary panic as people try to save themselves from broken glass bits.Now imagine this – An earthquake strikes. Before you have had a chance to grasp what’s happening, your arm bleeds from a cut by a jagged piece of glass that catches you by surprise.
You look up to see exploding glass facades and razor sharp bullets of glass coming your way from all directions and you don’t have a moment or a place to escape.
Does this scene remind you of a typical Hollywood movie? But it’s not. It can actually happen.
Recently the capital has witnessed a surge in buildings with whole front facades of glass. Inspired by international design, mainly those of churches and corporate houses, designers have incorporated glass in their plan without taking any measures to make it safe.
“If an earthquake like that of 1934 were to occur again, maximum lives would be lost due to the broken glass panes of buildings. The glass panes might look nice in terms of aesthetics and design but in terms of safety, especially in an earthquake prone country like ours, it is a major flaw,” says Uday Sunder Shrestha, a civil engineer and ex-editor of Spaces, an architectural magazine.
Sharmila Shahi, marketing manager at Sunrise Apartments points out that glass is purely used for its aesthetic value. “Glass is appealing for two reasons – the way it looks and the way it allows light to flow into your home.
We use simple glass for this purpose,” she said adding that natural disaster is not in anybody’s control and they don’t think in those terms while putting up glass panels in their buildings.
Windows are most definitely an important architectural structure and functional components of any building but the likelihood and extent of damage or casualties because of the glass used in them, in case of a major earthquake, is unimaginable.
In case of disasters, flying debris is the main cause of the greatest number of injuries with glass posing the biggest threat. Glass fragments can get into the eyes and razor-sharp slivers of glass can even slice bystanders.
The thought is what worries Uday who has time and again reiterated his statement of how maximum damage in case of a disaster would be because of these glass facades.
Dibya Acharya, final year student of Architecture at Institute of Engineering (IOE) talks about the need for safety while designing a high rise building.
“We are taught about the various types of glasses that are available and how they should be incorporated in our design keeping the safety aspect in mind.
For exterior design, toughened glass is the best option. I wonder why the buildings that are coming up are not paying any attention to it,” she says shaking her head to show her disapproval.
“If I were to design a building I’d focus on the glass and make sure they were strong enough. I fail to understand how such an important aspect of design can be neglected and not given enough importance especially when we all know that an earthquake is inevitable.”
The government, however, has set strict standards for the thickness of glass that should be used in high rise buildings.
It has till now has given its approval for 18 storied high buildings setting the required thickness of glass panes at six to eight millimeters while the thickness required for a mere three storied high building is five millimeters.Rajendra Khatiwada, an architect at Department of Urban Planning and Building Construction says that though the government has not set codes for the use of glass materials in buildings, the government is concerned about its impact in case of an earthquake.
Hence it only approves of building plans after advising the people concerned with the building project about the thickness of glass that should be used.
But since there are no strict laws implemented for the use of glass in buildings, Khatiwada is skeptical of the fact that builders are abiding by the rules and incorporating glass of the required thickness in their design plan.
Hema Shrestha, structural engineer at National Society for Earthquake Technology (NSET) says, “We are aware of the risks glasses pose in case of an earthquake. Damage to infrastructure is not the only potential hazard. Serious injuries and loss of lives could be some of the major treats of the glass facades.”
Toughening of glass could be one solution to minimize the risk of breakage and the subsequent damage. The other could be using as less glass materials as possible in buildings chimes in Uday.
“If you think about it, whole facades of glass are really not necessary. But if you like the aesthetic value of it, then at least get it toughened.”
Safety is the main advantage of toughened glass as it reduces the risk of injury caused by jagged glass shards as large shards of broken glass will not crack off and fly through the air when the glass is broken.
Toughened glass is 4-5 times stronger than annealed glass of the same thickness. The procedure of toughening glass involves heating ordinary glass to a very high temperature (around 620 degree Celsius) and cooling it rapidly when it begins to soften.
These types of glass not only provide enhanced security to windows but when it breaks it shatters evenly and crumbles into small cuboids that won’t cause any bodily harm.
While buildings that are being constructed have the option of toughening the glass that will be used, for the old existing buildings that can’t have their glass replaced an equally good alternative can be protective glazing.
“Protective glazing will strengthen the glass to some extent. I’d advise people to get at least one side of their windows laminated if they can’t laminate both sides. For the existing buildings this is a very good option,” says Hema.
Lamination or protective glazing can be the perfect solution for protecting the glass windows against the deterioration due to air pollution and for the conservation of energy as glazing also lessens the amount of heat lost through windows.
However, the most compelling argument for the installation of protective glazing is to combat breakage. This will minimize breakage however it is not as effective as toughening of glass.
Santosh Bisht, technical advisor at Nepal Peace Trust Fund GIZ bought an apartment as an investment at Sunrise Apartments, Dhobighat.
Though he does not live there, his parents occasionally do when they are visiting and during those times he worries about their safety.
“The building has comparatively smaller windows but glass is glass. Having heard that glass behaves like bullets in case of breakage, I am very worried about my parents’ safety.”
The government is also worried about the threat breakage of large glass facades pose and has set up a revision committee to tackle this sensitive issue.
“The building code section is making the necessary changes and soon we will seriously start advising people to pay attention to the detail of using toughened glass in their buildings,” shares Khatiwada.
“The main reason why toughening of glasses is not being done is because it is a costly method. But building constructors and architects should keep in mind the safety aspect of it and understand that it is not just a good investment but a necessity,” shares Uday.
Protective glazing and toughening of glass is simply not a matter of following the building code requirements.The builders should take the safety of the future building occupants and the public alike into consideration and get the glasses tempered or just opt to use less glass else the repercussions of it after a natural disaster will be insurmountable.
source: republica,16 March 2012
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