By now, we all know that Covid-19 is spread through respiratory droplets. While we are locked down in our respective homes, we are all looking forward to getting back to work in some form or the other, and are wondering how this is possible in the time of Coronavirus. How can workplace transmission be prevented? How should facility managers of industrial units and commercial facilities modify their operations to ensure employee health in the face of Covid-19?
How should healthcare facilities work to prevent cross transmission of Covid-19? To answer these questions, the Indian Society of Heating, Refrigerating & Air Conditioning Engineers (ISHRAE) and IFMA assembled a task force, consisting of members from academia, designers, manufacturers, service providers and subject matter experts of related sciences such as filtration, healthcare facility design, indoor air quality, safety, thermal comfort, system design and operation & maintenance. This task force examined, analysed and compiled information about the climatic conditions of the Indian subcontinent, referred to peer-review journals and reports from around the world, and put together a Covid-19 guidance document for air conditioning and ventilation.
Some of its general recommendations for various facilities include reduction of indoor dust levels, maintaining relative humidity between 40-70%, and setting temperatures between 24°C and 30°C (more the humidity, lower the temperature).
It categorises industrial and commercial facilities based on the type of indoor units installed, and recommends that indoor environments be ventilated with outdoor air as much as possible. However, it also points out that mechanical ventilation systems and air conditioning systems, which provide ventilation, can perform this function more effectively than simply opening the windows. The document contains industry-specific guidelines like keeping the heat recovery wheel in off mode to reduce cross contamination.
It mandates that a minimum fresh air volume of 3 cum/hour per person and 3.75 cum per hour per sqm (5 cfm per person and 0.6 cfm per sq ft) must be provided. Minimum air changes of around 10-15 ACHP is advised for good ventilation. The mechanical exhaust air should be 70% to 80% of fresh air quantity. It also specifies ways to disinfect the HVAC system itself.
A separate section on healthcare facilities includes practical ways to convert general patient rooms into covid-19 isolation areas by modifying ventilation, how to treat exhaust air from such areas, and the setting up of makeshift isolation centers. The document concludes with an exhaustive list of ways to operate and maintain equipment, as well professional and personal instructions for technicians.
