planning:building_services:ventilation:differentiation_between_vv_and_vn50_values
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planning:building_services:ventilation:differentiation_between_vv_and_vn50_values [2019/11/14 08:36] – [Single family house - Calculation of TFA, VV and Vn50] cblagojevic | planning:building_services:ventilation:differentiation_between_vv_and_vn50_values [2023/01/30 11:38] – [Calculation methodology] zbastian | ||
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| Reference volume of the ventilation system | | Reference volume of the ventilation system | ||
| is used to calculate the air exchange rate | is used for the calculation of n< | | is used to calculate the air exchange rate | is used for the calculation of n< | ||
- | | Rough calculation: | + | | Rough calculation: |
The next sections provide a detailed description of both values and their calculation. | The next sections provide a detailed description of both values and their calculation. | ||
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===== Vn50 – Net air volume for pressurisation test ===== | ===== Vn50 – Net air volume for pressurisation test ===== | ||
- | The air volume V< | + | The air volume V< |
- | ==== Calculation methodology ==== | ||
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- | The base area of each room should be multiplied by the average clear height of the room. Overall assumptions for determining the internal volume of the enclosed space (gross volume) by means of a reduction factor are not permissible. \\ | ||
- | The base area to be used for this calculation differs from the treated floor area (TFA) which is normally used. The TFA follows certain rules and applies certain percentages for considering areas from the energy use point of view. The base area for consideration the V< | ||
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- | As mentioned before, the V< | ||
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- | A full and comprehensible room-by-room calculation of the volume must be provided for each airtightness measurement. Auxiliary calculations may also be necessary; these must also be provided. For example, in the case of inclined roofs, the air volume is determined by means of triangular or prism calculations. | ||
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- | Visible rafters, beams, plasterboard encasings, wall-mounted installations (if these do not have the same height as the room) and the like are not taken into account; in the calculation they are not deducted for simplification. They are thus treated as if they did not exist (= air space). | ||
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- | The volume of window reveals is not taken into account either (measured only up to the inner wall surface). The same applies in the case of doors and openings. Please note that these stipulations are for the purpose of simplification. Any deviations occurring as a result are usually small. | ||
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- | Moreover, the volume of a stairwell is part of the air volume and is fully taken into account. | ||
- | Therefore, the base floor area of the stairwell is simply multiplied by the clear height of the storey. The volume for flights of stairs and intermediate landings does not have to be subtracted. | ||
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- | The volume of elevator shafts and any other kind of shafts inside the thermal envelope are part of the air volume and is fully taken into account. The volume of the elevator, pipes etc. themselves (building component) is not taken into account, therefore it is not deducted. The base area of the shaft can thus be multiplied with the clear height of the storey. | ||
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===== Example ===== | ===== Example ===== | ||
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| Sections of example calculation project: The area to be considered for the V< | | Sections of example calculation project: The area to be considered for the V< | ||
- | [{{: | + | [{{: |
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A more detailed explanation can be found in the following sources: | A more detailed explanation can be found in the following sources: | ||
- | [[http:// | + | [[http:// |
[[planning: | [[planning: |
planning/building_services/ventilation/differentiation_between_vv_and_vn50_values.txt · Last modified: 2023/01/30 11:52 by zbastian