What ASHRAE 62.1 and 62.2 are
- ASHRAE 62.1 sets minimum outdoor-air rates for commercial buildings; 62.2 covers homes. UAE green building codes and MEP consultants reference 62.1.
- Both dilute CO2, odours and pollutants. Neither sets a humidity target; current editions of 62.1 only cap indoor dew point at about 15.5°C at design conditions.
The default rates, in plain terms
- 62.1 office: 2.5 L/s per person plus 0.3 L/s per m². A 100 m² office for 10 people needs about 55 L/s (200 m³/h).
- 62.2 home: 0.15 L/s per m² plus 3.5 L/s per bedroom plus one. A 300 m² four-bedroom villa needs about 62 L/s (225 m³/h) continuously.
- Rates vary by space type and edition; the standard's tables are the reference.
Why undried outdoor air causes mould in the UAE
- Dubai summer air at 35°C and 70% humidity has a dew point near 28°C. Bring 225 m³/h of it into a 24°C home undried and every cold surface condenses.
- A fresh-air duct that bypasses the AC coil adds litres of water a day.
Meeting the rate without the moisture
- A ducted fresh-air treatment unit dries and filters outdoor air before the ducts.
- A fresh-air and heat-recovery dehumidifier does the same and recovers cooling energy from the exhaust air.
Where this applies
