Noise during test blast increased by 16db in 1 sec: Report
Noise levels around the Supertech twin towers in Noida’s Sector 93A increased by 16 decibels within one second during the test blast which took place on April 10, according to a report prepared by the Uttar Pradesh Pollution Control Board’s (UPPCB), officials said on Wednesday.
However, officials said that the increase was marginal and would not impact residents. Noise levels are expected to be similar on the day of the actual demolition as well, they added.
Officials of the pollution board said they set up a noise pollution monitoring device at the site before and during the blast. It recorded a noise level of 53 decibels before the blast and 69 decibels during the blast-marginally higher than normal. According to prescribed norms, noise levels in residential areas are supposed to be 55 decibels during the day and 45 decibels during the night. “We have been told by the demolition company that the noise level on the demolition day would not be very different, and only the duration of the sound will increase from one second to about nine seconds. A deflection of 16 decibels is not very high,” said Praveen Kumar, regional officer, UPPCB Noida.
According to officials of Edifice Engineering, the demolition contractor, the entire process will involve a series of blasts one after the other.
“Though it may appear as one implosion, the process actually involves pulling down one column after the other like a pack of cards. So, the noise levels will be more or less similar to the test blast day, but will last longer,” said an official of Edifice Engineering, requesting anonymity.
According to the UPPCB report, air pollution levels in the area were also within normal limits during the test blast.
A mobile air pollution monitoring
device could not be placed inside the blast site due to safety hazards, but the closest automatic air quality monitoring device at the Amity University campus in Sector 116 across the expressway recorded an Air Quality Index (AQI) reading of 113 in the “moderate” category on the day of the blast.
An AQI reading between zero and 50 is considered “good”, 51 and 100 “satisfactory”, and 101 and 200 “moderate”.
“The air pollution around Supertech was minimal since just a few columns were razed. There was hardly any visible dust at the site too. However, the conditions would not be the same on the day of the blast. There will be a lot of dust and rubble. However, all necessary arrangements are being made to minimise the impact and we are continuously monitoring what the company is doing with the generated debris. Water is also continuously being sprinkled at the site to control dust,” said Kumar.
Issue over deadline extension
The 32-storeyed twin towers— Apex and Ceyane—were supposed
to be demolished on May 22 following Supreme Court’s February 7 orders.
While the preparations are being made at the site, officials requesting anonymity said that Jet Demolitions, the partner of Edifice engineering and expert company hired to design and execute the demolition, will take more time to ready the building and the date of demolition may need to be extended.
Sources said that Edifice Engineering wrote to Supertech earlier this week seeking an extension for the date of demolition, saying the company needs more time to prepare the building considering the several risk factors involved. However, the Noida authority does not support the extension of the deadline.
“It is the builder’s responsibility to take up the matter with the Supreme Court before finalising anything. A timeline extension would be a violation of the earlier agreement. The authority won’t be able to extend timelines,” said Ritu Maheshwari, chief executive officer, Noida authority.
A representative of Supertech could not be contacted for comment.