A continuous mechanical extract ventilation system could consist of one of the following.
- A central extract system is known as MEV (mechanical extract ventilation).
- Individual rooms with continuous extract fans are known as dMEV (decentralised mechanical extract ventilation).
- A combination of both MEV and dMEV.
It also requires correctly sized and fitted trickle vents to be installed.
Requirements for ventilation rates are measured in both boost rates and continuous rates.
The minimum High (Boost) extract rates for a continuous mechanical extract for each wet room are found in Table 1.2
Table 1.2 Minimum extract ventilation rates for continuous extract systems (1)
Rooms | High rate (l/s) | Continuous rate |
|---|---|---|
Kitchen | 19 | The sum of all extract ventilation in the dwelling on its continuous rate should be at least the whole dwelling rate given in Table 1.3 |
Utility room | 8 | |
Bathroom | 8 | |
Sanitary accommodation | 6 | |
Note 1. No extra ventilation is needed if the continuous rate provided in a room is equal to or higher than the minimum high rate specified in the table. | ||
The total combined rate of continuous ventilation in the dwelling needs to meet the minimum rates found in Table 1.3
Table 1.3 Minimum whole dwelling ventilation rates by the number of bedrooms
Rooms | High rate (l/s) |
|---|---|
1 | 19 |
2 | 25 |
3 | 31 |
4 | 37 |
5 | 43 |
Notes 1. a minimum ventilation rate of 13l/s should be used if the dwelling only has one habitable room. 2. For each additional bedroom, add 6l/s to the values in Table 1.3 | |
