Table 2.
HVAC operation before and after the COVID 19 pandemic.
| Operations | Before ASHRAE 62.1 | After Guidelines | ≠ | |
|---|---|---|---|---|
| Ventilation | Outdoor Air | 10% − 80% (a) | ≥100% | |
| Re-entrainment | 20% (b) | none | ||
| ERC/Exhaust air transfer rate | ≤ 10% | ≤ 3% | 7% | |
| Outdoor air rate per person (CFM) | 5 | 21.19 | 16.9 | |
| Outdoor air rate per area (CFM) | 0.06 | 0.12 | 0.06 | |
| Air distribution | Mechanical | Across rooms | w/ across rooms | |
| Mechanial + natural | – | Under climate assessment | ||
| Filtration | MERV | 8 | 13 | |
| HEPA | – | Lobbies and entrances | ||
| UVGI | – | UV-C light devices | ||
| Indoor comfort | Temperature | 60 – 70 °F | ||
| Relative humidity | 60 – 70% | 40–60% |
(a) ASHRAE 62.1 — Climate zone dependable
(b) ASHRAE 62.1 — Class 1, dilution factor of 5.
(c) ASHRAE TC 5.5 — Static Pressure Differential under 0.5 in w.g.