From: Heating, ventilation and air conditioning (HVAC) in intensive care unit
Country | Recommendation society/association (reference) | Temperature | Relative humidity | Filtration | Pressurization | Air change (outside air/total) per hour [ACH] | Specific highlights/key differences |
---|---|---|---|---|---|---|---|
Type of ICU—general | |||||||
 Australia | QHFG [5] | 21–24 °C | 30–60% | G4–F8 | Positive | 2/6 | Filtration: Standards varied from MERV 7–8 to MERV 15. Few recommend HEPA filters (MERV ≥ 17). Pressurization: Positive pressure inside the ICU zone is recommended by Australian, UAE and UK societies, while neutral pressure is recommended in Germany, India, USA and recent UK HTM 2025. Temperature: Wide range varying from 16 to 25 °C. Relative humidity: Majority suggests 30–60% range whereas Indian and German recommendations remain silent. ACH: HTM 2025 (UK) strongly discourages the use of re-circulation type HVAC, presumably to avoid recirculation of airborne pathogens. Air distribution pattern: There exists no specific recommendation of air distribution pattern |
 Germany | VDI [6] | – | – | F9 | Neutral | – | |
 India | 16–25 °C | – | 99% efficiency till 5 μm | Neutral | 2/6 | ||
 UAE | DHA [9] | 21–24 °C | 30–60% | HEPA | Positive | 2/6 | |
 UK | 18–25 °C | – | F7 | Positivea | 10 (total)b | ||
 UK | HTM 2025 [12] | 20–22 °C | 40–60% | – | Neutral | 100% FA | |
 USA | AIA [13] | 21–24 °C | 30–60% | – | Neutral | 2/6 | |
 USA | ASHRAE [14] | 21–24 °C | 30–60% | – | Neutral | 2/6 | |
Type of ICU—burn | |||||||
 Australia | QHFG [5] | 21–32 °C | 30–95% | G4–F8 | Positive | 3/6 | Filtration: Australian recommendations suggest filtration similar to general ICUs whereas the USA recommends HEPA filtration of incoming air. Pressurization: Positive pressure isolation is recommended by Australia and the USA, whereas the rest have no mention. Temperature: Higher range (21–32 °C), in comparison to general ICU, is recommended by QHFS. Relative humidity: Higher range (up to 95%), in comparison to general ICU, is recommended by ASHRAE. Air distribution pattern: It should be ‘laminar’, as recommended by ASHRAE. |
 USA | ASHRAE [14] | – | 40–60% | HEPA | Positive | 3/6 | |
Type of ICU—neonate | |||||||
 Australia | QHFG [5] | 22–26 °C | 30–60% | G4–F8 | Positive | 2/6 | Filtration: There is no mention of air filtration standards by the USA whereas Australia suggests similar filtration standards as general ICUs. Pressurization: Australian recommendations suggest positive pressure whereas the USA recommends neutral pressure Temperature: Slight higher range (22–26 °C) is recommended in comparison to other ICUs. Relative humidity: Neonates having similar RH as in adults is a concern Air distribution pattern: There exists no specific recommendation of air distribution pattern |
 USA | ASHRAE [14] | 22–26 °C | 30–60% | – | Neutral | 2/6 |