How to Operate Air Conditioning and Ventilation Systems to Control Spread of COVID-19: Govt Issues Advisory

New Delhi: The Central Government has issued an advisory regarding the use of air conditioning and ventilation systems to control spread of coronavirus disease (COVID-19) in residences, workspaces and healthcare facilities.

The advisory, issue by the government, was a compilation of guidelines by the Indian Society of Heating Refrigerating and Air Conditioner Engineers (ISHRAE) and were shared by the Central Public Works Department (CPWD).

The ideal temperature that should be maintained in any house or office amid the coronavirus pandemic is between 24-30 degrees centigrade, the advisory said.

It also said that the relative humidity should be maintained between 40-70 per cent.
Evaporative coolers must draw air from outside to ensure good ventilation.

Fans, such as ceiling and Pedestal type, should be operated with windows kept partly open. If an exhaust fan is located at a nearby location then it must be kept running to exhaust air for better ventilation.
To prepare the advisory on the use of ACs in homes and offices, a COVID-19 task force extracted, examined and analysed information related to the climatic conditions of the country. The team members responsible for the extraction and analysis comprised of academia, designers, manufacturers, service providers and experts in healthcare facility design, indoor air quality safety and filtration.

“Recirculation of cool air by room air conditioners must be accompanied by outdoor air intake through slightly open windows and exhaust,” the document suggests.

“In dry climates do not allow the relative humidity to fall below 40 per cent. Water evaporating from a pan kept in the room will increase humidity if it falls below 40 per cent,” it added.

The panel suggests that the rooms should be kept ventilated even when ACs are not running. “As an extra precaution the frequency of service can be increased,” it said, adding, “If an exhaust fan is located nearby then it can also be switched on to exhaust air for better ventilation”.

For commercial and industrial facilities, the document recommends ventilation with outdoor air as much as possible. “The mechanical exhaust air shall be 70-80 percent of the fresh air quantity to maintain necessary positive pressure in the space,” it said.

“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”.

“Further there may be bird droppings, and excreta of rodents as well increased level of insects,” the advisory added.