Application
Demountable Fire Barriers
Fire Rating
240 Minutes
Pressure Rating
±2.5kPa
Project Duration
4 Weeks
Company background
Kolkata Metro Rail Corporation (KMRC) is a Government of India enterprise, established as a joint venture between the local and national government. KMRC was formed in 2008 to implement the Kolkata Metro Line 2 project, the second of six planned lines through the city.
As the first Indian city to launch a metro service, KMRC was tasked with continuing an impressive legacy, while also aiming to complete the line more quickly than Line 1, which was finished in 2010. Running partly underground, Line 2 is the first to run under the Ganges river, a major engineering triumph.
Project challenges
Invicta was contracted to supply and install passive fire protection for mechanical and electrical rooms in two metro stations, Phoolbagan and Sealdah. The walls of these rooms were required to provide fire protection, while also maintaining easy access to these areas for repairs and transit.
The equipment in these rooms occasionally requires maintenance, meaning that it has to be transported through tight underground spaces. However, this is usually done in stages, with some equipment remaining active while other pieces are being removed. As such, the end client wanted to reduce the cost of repairs without compromising on the fire and pressure resistance of the barriers.
Technical constraints
These machine rooms would need to be isolated from the rest of the station in the event of a fire, allowing the station to evacuate unimpeded, and giving the emergency services ample time to respond. However, the barriers would also have to withstand the unique pressure demands of an underground station.
The trains pulling in and out create what’s known as a piston effect, where the pressure rises as the train enters and falls as it leaves. This can put strain on the surrounding infrastructure, which could be damaged if this is not taken into consideration.
Installed solution
Invicta opted to install six demountable barriers in Phoolbagan, while four were required in Sealdah. These partitions offer a four-hour fire rating and can withstand pressures of ±2.5kPa, protecting both against the threat of a machine or electrical fire and the pressure exerted by the passing trains.
Key benefits
Unlike a gypsum or concrete partition, demountable barriers allow the walls to be removed without destroying the material and having to rebuild it. This allows the barriers to be quickly refitted after the equipment is removed, ensuring that the fire protection around the rooms is not compromised. On top of these benefits, Durasteel barriers can also be installed in as little as a quarter of the time of concrete barriers.
End result
The project was fully completed in four weeks by a team of six Invicta operatives.
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