BREEAM is an assesment method and agency for the certification of buildings sustainability. It defines requirements that building projects should meet to get a sustainability certification.
Among the various requirements, a number of them are grouped in a particular category called "HEA 01 Visual Comfort". Visual Comfort requires the calculation of 2 specific criteria called:
DL-Light helps the designer to calculate these indicators directly inside SketchUp.
As this calculation is based on the same process as other daylight autonomies, we recommend that you get familiar with general Daylight Autonomy calculation.
We will not go in depth in the definitions of these criteria. For details about them, we recommend that you check the abundant documentation provided by BREEAM.
The requirements are based on the following calculation :
The general procedure is complex and DL-Light provides a simple interface to perform these calculations and explore results.
Open SketchUp model. Follow next instructions to prepare your model for DL-Light calculations.
Open Daylight Autonomy dialog from toolbar or menu option Extensions -> De Luminae -> Daylight Autonomy -> Daylight Autonomy Calculation and enter the parameters of the calculation.
Project name - Project name is used during export and for output filename generation. The SketchUp model name is used by default.
- Directory where model will be exported for calculation.
When calculation is started model geometry and resulting files will be saved in 'da_output' subdirectory.
For SketchUp projects on a remote computer, read details in Remote files.
Mode - Calculation mode selection:
Label - Selection of BREEAM type to calculate:
Space - Sélection of space type to calculate:
For example, if the building being studied is a school, there may be dozens of classrooms and some other spaces such as catering. Set the default space as school, all classrooms will have this type, and then set the specific function of the catering space.
Requirements - Display of the BREEAM requirements corresponding to the BREEAM type and selected space.
Grid and units - Sensor grid and units are not displayed:
For BREEAM calculation it is required that sensors are positioned at a predefined distance from the floor surface: 0.70m for spaces of any type, and 0.85m for industrial spaces. To be able to position sensors on this height it is necessary to create virtual surfaces for every space you want to calculate.
Select floor surface(s) in SketchUp model, activate Copy surfaces tool from toolbar Surfaces will be automatically created, you only need to type offset from original surface. For DA calculation default offset is 0.70m, and it can changed at the bottom of SketchUp dialog. To exit from the tool press 'Enter' or 'Esc' button.
Ground albedo - Percentage reflection of the ground. Value can be selected from drop-down list or defined custom value in next dialog.
Location - Building location coordinates. This info is used to define an overcast sky luminance distribution. Location can be based on SketchUp model location, current Weather file location or be Custom. Below is dialog for Custom location definition.
Weather - Select annual weather file for the building location in Energy Plus weather file format. The weather file can be selected in the list provided by DL-Light or downloaded from Internet. See page Weather data.
Time zone - Display of the time zone used for the calculations.
The time zone is defined by the selected climate
Nota: when a model is located in SketchUp, SketchUp proposes a time zone based on the longitude of the place. This value is sometimes wrong, especially for Europe or Asia countries.
Period - Period of analysis. The daylight autonomy indicator is normally calculated over the year, but for specific analyzes a period can be chosen:
Default seasons are defined for northern hemisphere. Advanced parameters allow to use different definition of seasons. Read season definition.
Full days - occupancy range from 0h00 to 23h59 on the day range (end date included). Click on the input box and choose the date in the calendar, or enter it directly.
In trial version of the extension only 'summer' and 'winter' periods are supported. For more details read License information.
Define materials characheristics.
Since calculation is done with verified Radiance tools it is necessary to 'attach' physically based material to each layer in SketchUp. Note that materials should be defined with their solar reflectance and transmittance.
The tab of choice of materials:
Materials panel consists of two main parts:
To attach a material, select in the table layer(s) and either
double-click on required material in the tree or select the material
in the tree and press Attach/Detach button.
To detach from the layer(s), select it and click Attach/Detach button.
To revert all layers to previous state press Revert button.
The false color palette is updated for BREEAM requirements.
The 4 default colors are set to allow a readable display directly in the SketchUp model.
After all data are entered in DA dialog, select one or few surfaces and press Render or button.
Calculation time depends on number of selected surfaces, level of sensors details and model's complexity.
BREEAM results are imported into the SketchUp model. They should be interpreted differently than other DA results.
The calculated surfaces are unicoloured, according to the criteria satisfied by the surface.
After results are imported into the model, the detailed data is visible for each sensor on the surface:
To comply with BREEAM requirements, all surfaces must be colored green (BREEAM requirements for minimum illumination and average illumination are met). If some surfaces aren't colored in green, you can explore in report BREEAM detailed values, in order to determine what should be improved in the model to meet BREEAM requirements.
The BREEAM report
The top part of the dialog contains info about calculation
parameters - name of BREEAM standard, illuminance threshold
values, calculation period and occupancy profile.
Below is part with two indicators which inform user if BREEAM requirements for minimal and average illuminance are satisfied.
When user hover over these indicators, information about percent of total area with acceptable minimal/average illuminances is shown.
If an indicator is red, the requirement is not satisfied. If it is green, it is satisfied.
Lower part of the window is an interactive table where user can explore results for each surface.
If some of space type cells have red text it means that
results were calculated for one space type, and then user
changed space type but has not repeated the analysis.
Note that the results in the table are correct, and are just reminder for user that space type was changed in GUI.
In the bottom of the dialog are few useful buttons: