11.209 SUMMARY 1) I suggest that in every organization an experienced HVAC engineer should oversee each total COVID-19 protection plan regarding HVAC alterations. Organizations employ people with varying types of expertise, however having a governing expert to provide oversight during this pandemic will ensure integration of knowledge, identification of gaps and overall success. 2) The effectiveness of the MERV13+ filters in capturing the COVID-19 virus should be verified. If 100% effective, return air filtration may allow conservation logic to remain, respecting the Climate Change threat. 3) A study assessing the virus content at HVAC locations presented on page 11.203 is required via a credible governing body. Understanding the locations of the virus is critical to establishing a safe plan. 4) The air from the supply fan must be viewed differently at two separate locations in the HVAC system. The airflow should first be considered from the supply fan to where it enters the occupied space and secondly as a different airflow as it passes over people in the occupied space. Completely virus-free air entering the occupied space can possibly pick up and transfer viruses between occupants in the space. Alterations to the supply air at the fan will be pointless if the air is already clean and the virus transfer is only within the occupied space. 5) If the virus cannot be in the return air at the entrance to the mixed air plenum by either return air filtration or the virus being incapable of travelling that far, allowing recirculation of air as per existing conservation logic should be considered respecting the Climate Change threat. 6) The impact of humidity levels between 40% RH and 60% RH on viruses and human health should be clarified. ASHRAE and REHVA have differing opinions. ASHRAE indicates between those RH values, viruses are less dangerous and humans’ health is improved. If ASHRAE is correct, flushing with maximum quantities of cold fresh air is beneficial to the virus and detrimental to humans, because it will reduce relative humidity levels in the occupied space. 7) Information is changing on this issue as research is being reported. Everyone is putting their best effort into solving this common threat. Working as a positive team has value. 8) Questions, constructive criticism on any points or added information will be appreciated. 9) Acceptance and application of any concepts suggested in this report is the total responsibility of those designing, installing and commissioning the individual projects.
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