As metro rail services are set to resume in Chennai from Monday, Chennai Metro Rail has taken measures to ensure safety of passengers at underground stations against Covid-19 infection. Nineteen out of the 32 stations are underground.
The measures include adding two layers of air filters in the air handling units to filter particles as small as five microns. The primary filter can trap particles of 10-micron size and the secondary filter can trap particles five micron size. In addition to this, the air circulation paths are fitted with UV ray emitted which can kill microorganisms present in the circulating air.
“Indoor air quality is maintained by including fresh air inside the station around four times more than the recommended levels and the fans are run continuously as per CPWD and ISHRAE protocol,” CMRL said.
Air filters, cooling coils, air diffusers and grills will be cleaned once a week with 1% sodium hypochlorite solution. Metro rail tunnels already have ventilation fans for drawing in outdoor air.
In a release, CMRL said it would maintain indoor temperature in underground stations between 24 and 30 degrees Celsius with a relative humidity of 40% to 70%. Temperatures inside trains will be around 25 to 27 degrees Celsius as per the guidelines from ministry of housing and urban affairs.