While designing your workplace policy and procedures to combat Covid – 19, do consider what you are doing about your indoor air quality.
A COVID-19 Task Force was set up by ISHRAE’s (Indian Society of Heating, Refrigerating and Air Conditioning) Technical Committee to determine the effect of indoor air quality on transmission of corona virus.
They found that the size of a corona virus particle is in the range of 80-160 nano-meters. It is transferred via infected microscopic airborne particles and contaminated aerosol droplets. Droplets and small particles of a broad spectrum of diameters get generated during the course of coughing & sneezing and , to a lesser extent, even by talking and breathing. It is known that most of the infectious particles ranging from 0.65 to 3.3μm in the cough-generated aerosols were immediately respirable.
As commercial spaces have multiple and transient visitors, it is this aspect that necessitates precaution in operating their air conditioning systems.
OPERATING GUIDELINES FOR ALL COMMERCIAL ESTABLISHMENTS
A) Air filters must be kept clean.
B) Provide adequate ventilation ( fresh air and exhaust ).
C) Inspect and clean the indoor unit coils.
D) Set room temperature between 24°C and 30°C. Maintain relative humidity between 40% and 70%. (in humid climates set temperature closer to 24°C for de – humidification and in dry climates closer to or at 30°C. Use fans to increase air movement).
E) Heat Recovery Wheel (HRW) : It is advisable to keep this wheel in off mode to reduce cross contamination. Upon restarting, the wheel must first be sanitized.
F) Toilet and kitchen exhaust fans must be kept in operating mode.