The vibrations triggered by aircrafts while taking off and landing and the temperature difference between the exterior and air-conditioned interior are the two most likely causes behind the recent shattering of glass sheets at the new Dum Dum airport terminal building, experts have told HT.
An official of a multinational glass manufacturing company revealed that glass has a tendency to develop cracks if the iron content is not removed during the manufacturing process. “A compromise in quality can’t be ruled out, since the AAI officials concentrated more on cost cutting,” the source revealed, on condition of anonymity.
Hindustan Times spoke to representatives of the Mumbai, New Delhi and Hyderabad airports, all of whom confirmed that none of these structures had experienced anything like the mass shattering of glass sheets witnessed at the new Kolkata terminal.
Altogether, around five sheets of glass have shattered since the terminal began full-fledged operations on March 15. The AAI actually had to replace about 150 sheets even before the terminal became operational.
Professor AR Choudhury, of Jadavpur University’s department of physics, said the glass was probably unable to withstand the sound waves being generated by the aircraft. “The glass could also crack if it has been fitted loosely, which isn’t likely in this case,” he added.
Airport sources revealed that the incidents had followed a similar pattern, known to experts as a butterfly pattern. In all the cases, a crack first appeared in the centre of the sheets before spreading until the glass broke under the stress.
“I think the cracks and shattering could have happened either because of sound waves by the aircraft or the temperature variation between the inside and the outside of the building,” Tilak Basu, former scientist of the Central Glass and Ceramic Research Institute, said.
The size of the pieces of glass that are crumbling is 4.5 sq. meters. More than 30,000 of these sheets have been used in the building.
Meanwhile, sources at the AAI said they had asked for an explanation from the companies - Asahi India, Gold Plus and Sezal Glass - that supplied the glass for the new terminal.