The Danish Building Regulations $ 379 Daylight states:
For relatively simple buildings, it will often suffice to examine a few selected rooms where there may be doubts about daylight access, if there is certainty that the rest of the rooms meet the requirements. It would usually be simplest to use the 10% rule. For the selected rooms, the boundaries of the space are defined, and the floor area and the glass area of the windows in the room are calculated. The actual glass area for each window must be corrected for conditions that restrict daylight access to the window as described in Guidelines of the Building Regulations on corrections to the 10% rule for daylight.
In homes there are varying daylight needs. Therefore, a slightly lower daylight level can usually be accepted in children's rooms and bedrooms if the glass area without correction for shady conditions for the specific compartments corresponds to at least 10% of the relevant floor area, while the daylight level is Respected for the residential rooms as a whole, i.e. The sum of the glass area with corrections for all living space accounts for at least 10% of the total floor area for these spaces.
Daylight conditions at workplaces longer than 8 metres from the façade will normally have to be documented in the calculation of illumination from daylight, as the method of using glass area does not take into account very deep spaces.
Link to Daylight Application
All of the above regarding the correction guidelines to the 10% rule for daylight can be calculated with the Naviate Daylight application.
Application settings
- Under Settings, set the calculation standard to "Danish building regulations..."
- Add the missing glazing material names for the project.
- Set the transparency factor to "family type; visual light transmittance" or "material, shading, transparency" for which value you would like to use for "LT".
The LT transparency value can be read from the Revit glazing material, or the Revit window properties.
- Click "Ok". The daylight areas will now be calculated.
- Select which rooms are required to have daylight by changing the checkbox "requires daylight" for each room.
- You can also quickly change multiple daylight requirements per room at once, by using the "auto-fill required values". Type in the (part of the) room names and the required percentage; this is 0% for corridors (no daylight required) and 10% for living rooms and other occupiable rooms.
- Another option is to change the room parameter in Revit by selecting one or multiple rooms in Revit, and change the value "Required Window-to-Floor ratio"; 0% for rooms not needing daylight, and 10% for rooms needing daylight.
- You're now set for Danish Daylight calculation for your project!
Calculation
- For every window, the following reduction factors will be automatically calculated: (For more info see calculation method, shading factors)
- F;LT is the transparency factor property of the glazing. (see calculation method, transparency)
- F;OMG is the shading factor of elements in front of the window blocking the horizon. This is dependent on the average vertical shading angle (0 to 60°) going upwards from the horizon within a horizontal range of -45° to 45° perpendicular to the window. This factor might be different per window.
- F;OH is the shading factor of elements hanging above the window (overhang). This is dependent on the average vertical shading angle (0 to 60°) going forwards/downwards from the upper direction of the window within a horizontal range of -60° to 60° perpendicular to the window. This factor might be different per window.
- F;SF1 and F;SF2 are the shading factors of elements hanging left respectively right of the window (side wings). This is dependent on the average horizontal shading angle (0 to 60°) going inwards from the left resp. right sides of the window within a horizontal range of 0° (horizon) to 80° up perpendicular to the window. This factor might be different per window.
- F;RUM is the correction factor for rooms with large depth. This is dependent on the room depth perpendicular behind the window. This factor might be different per window.
- F;FL is the correction factor if more than one wall orientation in a room contains windows.
- F;OVLYS is the correction factor if the window is a roof light, when the slope of the window is 60° or less.
- F;ASF (blinds) and F;ATR (atria) are difficult to generically calculate from a Revit model, and therefore need to be included manually.
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| Frustum projection view for getting mean angle V;OMG of elements in front of the window blocking the horizon | Frustum projection view for getting mean angle V;OH of elements hanging above the window | Frustum projection view for getting mean angle V;SF1 and V;SF2 of elements hanging left respectively right of the window |
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| F;OMG example situation of a building opposite of the window | F;OH example situation of a balcony above the window. | F;SF example situation two walls giving shading left and right of the window. | F;RUM example situation calculating the room depth behind the window | F;FL example situation of a room having windows in multiple wall orientations | F;OVLYS example situation of a room with a roof light |
Reporting
Now make sure all rooms are green, by adding more windows, or changing window dimensions in Revit. When all rooms are green, daylight requirements are met, and results can be reported.
- You can report results by clicking the "Report" button. The application will now generate a Word document with all daylight results per room and per window.
- You can also generate a 3D visualisation by clicking the "Visualization" button, and you can generate a coloured "Revit floor plan" by clicking the Revit floor Plan.
- After clicking "save & close" all Daylight results will be saved as shared parameters in your project. You can make custom room and window schedules to report these calculated daylight values throughout Revit.
