Cover Story Techniques Enhancing the Acoustic Insulation of Glass • More thickness of outside and inside glass (6 to 8mm even to 10mm as per requirement). • Providing more space in DGU (16 to 20mm) • Use laminated glass • Use acoustic PVB • Use PVB laminated glass even for both. The above five factors will enhance the acoustic insulation value. We have to strike a balance between the requirement and cost, the cost increases with the number of steps. (Varghese PV, CEO, Glazing and Metal Works, Sobha Ltd)
insulates against sound is a hugely false perception, Singh points out. Agreeing with Singh, Rooprai too observes that a laminated glass fares better than an IGU unless the IGU is having a large air gap of 20 mm or more. “Using an IGU is a good solution for reducing the indirect solar heat gain (U-values) but not for acoustics, at least with the prevalent standard air gap of 12mm. Having air gaps more than 12mm is a big deterrent as it leads to increased overall framing system cost. Infact, it is better to use a single monolithic glass than an IGU,” suggests Rooprai. Glass is generally 90% of any
Image courtesy: GSC Glass Ltd
recommends PVB interlayered laminated glasses and insulated glasses which can provide 50–60% sound reduction. These glasses work well for buildings abutting the highways/railways, for hospitals and childcare centres. The progression for acoustic should be first to increase the thickness of the glass than to jump to DGU principals. Also, in the case of DGU, one should remember to create a differential in thickness, says Bij. Depending on the methodology of glass (thickness/DGU/lamination) the decrease in dB can be attained. A general understanding that insulating glass (IGU or DGU) also
Aloft Hotel, Delhi
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glazing, hence it plays a pivotal role when it comes to acoustic insulation, and there are a lot of myths and notions which needs to be addressed, points out Pathak. For example expectations in terms of decibel reduction, we can’t have a zero dB sound. Using the word sound proof is wrong. Sometimes there are multiple areas from where the noise can seep in or come but all the focus is given to glass hence making it extremely difficult to address the situation. When installing in a system, the gasket, the fabrication of the product, the installation and civil itself all of them play important roles. Glass manufacturing companies have done an excellent job in promoting and educating about high performance glass for thermal insulation, it is time for processors to do a similar working on acoustics. In modern façade, the initiatives taken to bring energy efficiency are enhancing its overall acoustic insulation, states Varghese. “As a thumb rule, we may look for a 40 decibel sound level inside, with a possible noise level of 70-80 decibel outside. Ideally, we aim for decibel reduction of 32dB to 44dB according to the nature of the space. High decibel reduction is desirable for the high-end hotels where the level of noise outside due to proximity to highway, railway station and flight path is high,” explains Varghese. AWARENESS LEVELS OF CONSUMERS The glass industry is growing at about 8-10% a year. Government regulations such as GST and RERA have affected the construction sector, which have pushed real estate developers, architects and designers to explore more options in ‘green building materials’, glass being one of them, says Khanna. At a consumer level, says Kembhavi, the awareness is improving drastically compared to