Schools Ventilation Progress

Note: NDIR sensors are superior to VOC types

Grade 0 (very poor)

• Fresh Air Ventilation: No mechanical ventilation or HVAC system. No windows or sealed windows that cannot be opened.
• Permanently closed windows aids temperature control but with a high cost of increased airborne disease transmission.
• Recirculation Air Cleaning/Filtering: No air filters or air cleaning mechanisms.
• PM2.5 Measurement: No PM2.5 monitoring.
• CO2 Monitoring (VOC or NDIR): No constant CO2 monitoring - maybe a unit is carried from room to room for spot checks.
  • CO2 Level: Always above 2000 ppm when fully occupied.
• Classroom Density: High classroom density (> 2.5 students per square meter).

Grade 1 (poor)

• Fresh Air Ventilation: Windows can be opened but no mechanical ventilation.
• Open and closinhg of windows reduces airborne disease transmission a little, but doesn’t work in every country due to the severity of the winter and/or summer.
• Recirculation Air Cleaning/Filtering: No HVAC system or limited to only heating/cooling. No air filters or substandard filters.
• PM2.5 Measurement: No PM2.5 monitoring.
• CO2 Monitoring (VOC or NDIR): CO2 monitoring intermittent and not automating ventilation.
  • CO2 Level: Often above 2000 ppm when fully occupied.
• Classroom Density: High classroom density (2 to 2.5 students per square meter).

Grade 2 (basic)

• Fresh Air Ventilation: Basic mechanical ventilation without automation. HVAC system with basic filters.
• Recirculation Air Cleaning/Filtering: Basic air filters or air cleaning mechanisms with limited efficiency.
• PM2.5 Measurement: PM2.5 monitoring may be present.
• CO2 Monitoring (VOC or NDIR): CO2 monitoring likely constant, but not automating ventilation.
  • CO2 Level: Mostly below 1500 ppm when fully occupied.
• Classroom Density: Moderate classroom density (1.5 to 2 students per square meter).

Grade 3 (getting there)

• Fresh Air Ventilation: Mechanical ventilation with basic heat recovery, partially integrated with CO2 monitoring.
• Recirculation Air Cleaning/Filtering: HVAC system exists with basic air filtering capabilities.
• PM2.5 Measurement: PM2.5 monitoring exists and actionable insights are provided.
• CO2 Monitoring (VOC or NDIR): CO2 monitoring constant and imperfectly automating ventilation.
  • CO2 Level: Mostly below 1200 ppm when fully occupied.
• Classroom Density: Moderate classroom density (1 to 1.5 students per square meter).

Grade 4 (good)

• Fresh Air Ventilation: Full mechanical ventilation with heat recovery and CO2-based control for optimal air changes.
• Recirculation Air Cleaning/Filtering: HVAC system with HEPA filters or equivalent for clean inlet air. Advanced air cleaning mechanisms for recirculated air.
• PM2.5 Measurement: PM2.5 monitoring and control measures actively reduce particulate levels.
• CO2 Monitoring (NDIR): CO2 monitoring fully integrated and automating ventilation system.
  • CO2 Level: Always below 850 ppm when fully occupied.
• Classroom Density: Low classroom density (0.5 to 1 student per square meter).

Grade 5 (excellent)

• Fresh Air Ventilation: Fully integrated mechanical heat recovery ventilation system (MHRV) with CO2-based control.
• Recirculation Air Cleaning/Filtering: HVAC system with high-grade filtration, ensuring filtered and fresh air.
• PM2.5 Measurement: PM2.5 levels consistently below 5 μg/m³.
• CO2 Monitoring (NDIR): CO2 levels consistently below 700 ppm with automated ventilation adjustments.
  • CO2 Level: Always below 700 ppm when fully occupied.
• Classroom Density: Very low classroom density (< 0.5 students per square meter).

• The country/state/province/city in question has building codes for schools (old or new) and performs inspections.

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