Air flow rates in residential buildings Marianna Luoma

Designing the air flow rates in residential buildings Determine the supply air flow rates in dwelling areas Determine the extract air flow rates Check that Air change rate is at least 0,5 1/h or 0,35 dm3/s,m2, but not more than 1,0 1/h Total extract air flow rate is about 5% higher than total supply air flow rate; increase the exctract air flow rates if necessary Design the boosting air flow rates and the air flow rates for the situation when the residence is not occupied

Designing the supply air flow rates Aim at 6 l/s,person or 0,5 1/h or 0,35 l/s,m2 Bedrooms are designed for two persons Bedrooms can be adjusted for one person, when the end-use is known The living room may ”borrow” supply air from the bedrooms

Designing the extract air flow rates Use the extract air flow rates given in the Table in the Appendix 1 in D2 Make sure, that extract is about 5% higher than supply air flow rate In the normal case, emphasize the extract from bathroom and toilet A separate exhaust at the cooker hood is recommended An air flow rate of 40…50 l/s is needed at the cooker hood to remove the smell from cooking activities

Air flow rates in the case of boosting and absence Boosting air flow rate of +30 % for the whole dwelling Not just through the cooker hood, but the extract from the bathroom and toilet and cleaning situation are more important Sound level may increase 10 dB, if the resident has the possibility to control the boosting When the occupants are away for a longer period of time, the air flow rates may be dropped with 60%

Design exercise 1 Design air flow rates for one-room flat (31 m2) In this case: The boosting of air flow rate can be controlled separately for each dwelling Room height is 2.6 m

An example of air flow rates in a small apartment (31 m2) 1 room + kitchen + sauna 31 m2 Dwelling Sauna Bath- Kitchen Σ Supply Σ Extract Air change Extract + Supply   area room (L/s) (1/h) D2 Table values D2 Boosting 30 % D2 Absence

smaller than extract air flow rate. You need to increase the supply. 1 room + kitchen + sauna 31 m2 Dwelling Sauna Bath- Kitchen Σ Supply Σ Extract Air change Extract + Supply   area room (L/s) (1/h) D2 Table values  +12  ±6  -10  -8  -18  0,8 -6  D2 Boosting 30 %  +15,6 ±7,8   -13 -10,4 -23,4   1 -7,8  D2 Absence -60 %  +4,8 ±2,4  -4  -3,2   -7,2 0,3  -2,4  Supply is flow rate is 33% smaller than extract air flow rate. You need to increase the supply.

Design exercise 2 Design air flow rates for two-room flat (63 m2) In this case: The boosting of air flow rate can be controlled separately for each dwelling Room height is 2.6 m

2 rooms + kitchen + sauna 63 m2 Bed- Living Cloak Sauna Bath- Kitchen ΣSupply ΣExtract Air SSupply+SExtract   room change (L/s) (1/h) D2 Table  +12  +10 values D2 Design D2 Boosting 30 % D2 Absence -60 %

STEP 1 2 rooms + kitchen + sauna 63 m2 Bed- Living Cloak Sauna Bath- ΣSupply ΣExtract Air SSupply+SExtract   room change (L/s) (1/h) D2 Table +12 +10 -3 ±6 -10 -8 +22 -21 0,5 1 values D2 Design D2 Boosting 30 % D2 Absence, -60 %

STEP 2 2 rooms + kitchen + sauna 63 m2 Bed- Living Cloak Sauna Bath- ΣSupply ΣExtract Air SSupply+SExtract   room change (L/s) (1/h) D2 Table +12 +10 -3 ±6 -10 -8 +22 -21 0,5 1 values D2 Design -14 -27 0,6 -5 D2 Boosting 30 % D2 Absence, -60 %

STEP 3 2 rooms + kitchen + sauna 63 m2 Bed- Living Cloak Sauna Bath- ΣSupply ΣExtract Air SSupply+SExtract   room change (L/s) (1/h) D2 Table +12 +10 -3 ±6 -10 -8 +22 -21 0,5 1 values D2 Design -14 -27 0,6 -5 D2 Boosting +15,6 +13 -3,9 ±7,8 -13 -18,2 +28,6 -35,1 0,8 -6,5 30 % D2 Absence, -60 %

STEP 4 2 rooms + kitchen + sauna 63 m2 Bed- Living Cloak Sauna Bath- ΣSupply ΣExtract Air SSupply+SExtract   room change (L/s) (1/h) D2 Table +12 +10 -3 ±6 -10 -8 +22 -21 0,5 1 values D2 Design -14 -27 0,6 -5 D2 Boosting +15,6 +13 -3,9 ±7,8 -13 -18,2 +28,6 -35,1 0,8 -6,5 30 % D2 Absence, -60 % +4,8 +4 -1,2 ±2,4 -4 -5,6 +8,8 -10,8 0,2 -2