Kochi

Blasts to bring down Maradu apartments today

Time is up: The two apartment complexes of Alfa Serene (left) and H2O Holy Faith that will be demolished on Saturday.

Time is up: The two apartment complexes of Alfa Serene (left) and H2O Holy Faith that will be demolished on Saturday.   | Photo Credit: H_Vibhu

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H2O Holy Faith and Alfa Serene to be knocked down at 11 a.m. and 11.05 a.m. respectively

H2O Holy Faith and Alfa Serene, the apartments built in violation of CRZ rules at Maradu, will be knocked down on Saturday using emulsion explosives.

The first blast will take place at the extreme right corner of the ground floor of H2O Holy Faith at 11 a.m., which will then spread to other floors at lightning speed. The explosive materials will go off one after the other at regular intervals, which have been pre-set using delay detonators. It may take 5.6 seconds to reduce the 16-floor building to rubble.

Also read: Maradu demolition: How the saga unfolded over 13 years

An expert team from the Petroleum and Explosives Safety Organisation (PESO), which inspected the apartment complexes on Friday evening for one last time, suggested relocating the initiation point from where the blast would be triggered at Alfa Serene. The initiation point was relocated some distance away from the earlier spot so as to minimise the possible impact of the demolition of H2O reaching the site. The new location will be 130 metres away from the building, said R. Venugopal, Deputy Chief Controller of Explosives, PESO.

Also read: Firemen to be the first responders at blast sites

The PESO team conducted the final round of inspections on Friday evening so that the sites were free of workers and officials. All wire connections and electrical connectivity were inspected. The wind conditions of the area were also gauged. Since the area is unlikely to have strong winds, the dust should settle in a few minutes after the implosion, said Dr. Venugopal.

The authorities have fully secured a house located close to H2O Holy Faith using geo textiles. No dust or fly-off material will reach the building. Going by the preparations, the first blast should take place at H2O Holy Faith at 11 a.m. and the second at Alfa Serene at 11.05 a.m., he said.

Evacuation of people from neighbourhood to begin at 7.30 a.m.

The technicians of Edifice Engineering, which will demolish H2O Holy Faith, will connect the wires from the initiation point to the building at 9 a.m. on Saturday. All connections were re-checked during the day to ensure that the blast takes place as planned. Eight sophisticated action cameras and four drones will be deployed to record the blast. The team members will arrive at the site at 8 a.m. to perform a pooja before the blast, said Uttkarsh Mehta, partner of Edifice Engineering.

Mr. Mehta exuded confidence that the buildings would come down as planned.

Also read: Demolition to go down as record for future generations

Alfa Serene will be connected to the initiation point at 10.30 a.m. on Saturday. Technicians of Vijay Steels, the agency that will bring down the structure, went around all floors of the building, checking the connections on Friday. The connections to all delay detonators were checked.

It was also ensured that all the 3,000-odd holes filled with explosives were connected, said Anand Sharma of Vijay Steels.

Also read: Maradu residents rattled by the exercise

Explosives to be used

•  A cocktail of emulsion explosives, ammonium nitrate and 6%  fuel

•  The fuel will start the ignition and create a blast

•  The electric trigger for the explosion will be created using a manually operated dynamo, which will be fixed at the initiation point

•  Explosion will be made using Super Power90 cartridges that have been filled in the holes that were drilled in the building

•  Non-electric trunk lines (delay systems for controlling the timing detonation) which can delay explosions by 6, 25 and 200 milli seconds have been used for connecting

the columns where cartridges of explosive materials are filled into the holes

•  Non-electric long period detonators that can delay the triggering of explosives by 6.5 sec have also been used to control the explosion

•  For H2O Holy Faith, the initiation point will be below the Kundannoor bridge, which is located 71 metres away from the building

•  A five-member crew will trigger the blast by a manually operated dynamo

•  Only licensed blasters will be permitted at the initiation point

The tentative list of blasters for H2O Holy Faith

• Joe Brinkman of Jet Demolition,  South Africa.

• Kevin Smith

•  One Indian blaster who is yet to be named

• Martinez

•  PESO/Maradu municipality representative

Other impacts

•  Possible sound levels due to implosion: 90 to 120 decibel

•  Permissible noise level in public places - 75dB for daytime

•  Air pollution levels based on the PM 10 (particles with a diameter of 10 or less) and PM 2.5 (particles of diameter 2.5 or less) levels of particulate matter to be assessed for a duration of eight hours from the time of implosion

•  The safe permissible limits for PM 10 and PM 2.5 particulate matter are 100 and 60 respectively

•  Possible vibration: 25 mm per sec

•  Rubble may pile up to a height of 16 metre

•  Instantaneous electric detonators will be used for taking the detonation to all points

Precautions being taken

1. Rapid Response Team near all sites for medical emergency

2. Four ambulances on Day 1 – two each at a site; one additional ambulance on Day 2

3. Private hospitals in the vicinity to aid Government medical team

4. Ambulance@108 on standby

5. Eight fire tenders on Day 1 – four each at a site

6. Fire tenders to be at 200 metres from implosion

7.   Control Room to order waterspray by fire tenders after two minutes of explosion

8. Water pumping to houses to be stopped during the operation

9. Electricity to be switched off

Problems expected

10. Dust to create visibility problems

11. People in the vicinity should wear good quality masks to keep dust away to avoid respiratory problems; cement dust could create problems for asthma patients

Dos And Don'ts

1. People are advised not to take pictures with mobiles of ambulances and fire tenders when they are on the move

2.  Do not cross the exclusion zone

3. Follow the instructions issued by the authorities

4. Watch the demolition from the safe distance

Pollution monitoring

•  Three stations set up near the sites  to monitor air pollution

•  Permissible noise level in public places - 75dB for daytime

•  Expected levels to be below the permissible limit as implosion to last for a few seconds only

•  Pollution Control Board to study water pollution in the wake of debris falling into Vembanad Lake

•  Samples already collected to correlate pre and post-implosion levels

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Printable version | Jan 29, 2020 8:05:05 PM | https://www.thehindu.com/news/cities/Kochi/blasts-to-bring-down-maradu-apartments-today/article30538889.ece

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