Coronavirus | Increase fresh air, limit use of central AC systems: CPWD

CPWD buildings to follow safety guidelines for AC, ventilation systems

For air-conditioning systems, whether at home or industrial or commercial spaces, the guidelines say that air filters should be kept clean. File (representational image)

Officials in charge of all Central Public Works Department (CPWD) buildings in the country have been asked to follow the safety guidelines issued by the Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE) on preventing the transmission of novel coronavirus through central AC systems.

Issuing the “guidelines for air-conditioning and ventilation” on Wednesday, the CPWD told all its field offices to implement the precautions as there were concerns that heating, ventilation and air-conditioning (HVAC) systems could be adding to the spread of COVID-19. Among the buildings maintained by the CPWD are offices of the Ministries in Delhi.

While many private businesses that have central HVAC systems are closed due to the lockdown, many buildings such as hospitals, hotels and other essential services are functional. The ISHRAE guidelines released on April 13 say that the use of HVAC systems should be limited and fresh air should be used to ventilate indoor areas as much as possible.

For air-conditioning systems, whether at home or industrial or commercial spaces, the guidelines say that air filters should be kept clean. The indoor unit coils should be inspected and kept clean. The temperature setting for the room should be between 24 degrees Celsius and 30 degrees Celsius and relative humidity between 40% to 70%. Fans should be used to increase air movement, the guidelines say and add that exhaust fans in kitchens and toilets should also be switched on.

In case of buildings that don’t have adequate fresh air, the guidelines say, an additional fresh air duct should be provided.

The guidelines also highlight the need for sanitisation and maintenance of HVAC systems once the lockdown ends.

“Most commercial establishments have remained closed during the lockdown. These establishments will need maintenance for both engineering and health safety. The air-conditioned spaces of establishments under prolonged lockdown will pose health hazards due to fungus and molds in the ducts and open spaces depending on the humidity and temperature prevailing within,” the guidelines say.