Users can document the USGBC LEED v4.0 / v4.1 - IEQ: Daylight credits using cove.tool's Daylighting 3D Analysis.
Before we begin
Download the Daylight and Quality Views Calculator from USGBC. The forms are available for both LEED v4.1 and LEED v4.0 versions of the credit. Cove.tool does not auto-generate credit documentation (though this is a planned feature), rather users can use the analysis from the app to complete LEED forms manually.
Before uploading geometry to cove.tool, users must distinguish between regularly occupied floor-area and non-regularly occupied floor-area (see full explanation if "occupied spaces" at the bottom FAQd). In the analysis model, a regularly occupied floor area is brought into cove.tool through the Floor Category export, and non-regularly occupied floor area through the Shading Device Category. Thereby only accounting for true analysis area, but still benefiting from possible lighting strategies related to high-reflective surfaces.s Only the floor area imported through the floor category will contribute directly to the final percentage views assessment. Also note that the cove.tool plugin's do not read Room Tags or other space denoting inputs, only elevation and surface area is collected when exported to cove.tool. Video tutorials for upload geometry with a plugin can be found on the App store, as well as troubleshooting articles.
Last, our calculation method follows the guidelines required by the IES LM-83: Approved Method: IES Spatial Daylight Autonomy (sDA%) and Annual Sunlight Exposure (ASE), and the BD+C LEED v4.0 IEQ - Daylight credit for sDA% and ASE% simulations by running a full ray-tracing simulation and calibrating within 1%-5% of a Radiance simulation. However, our RayTrace engine method is only compatible with permanently installed geometry. So buildings with dynamic facades, electrochromic glass, or other non-yearly fixed elements and strategies cannot pursue LEED compliance with cove.tool's sDA and ASE Full Floorplate Daylight Analysis. If your building cannot use cove.tool for documentation, it can still run the simulation for preliminary results and identifying if and how much further the design needs to improve to meet the compliant sDA% and ASE% threshold.
Written Tutorial for Documentation
Step 1 - Apply Settings for LEED compliant daylight simulation
According to LEED v4.0 IEQ c7. Daylight language, the following requirements must be met for Option 1:
- The analysis areas must cover all regularly occupied floor areas.
- The sDA and ASE calculation grids should be no more than 2 feet (600 millimeters) square and laid out across the regularly occupied area at a work plane height of 30 inches (76 millimeters) above the finished floor.
- Set the following Period of Analysis: An hourly time-step analysis for a full calendar year, January 1 to December 31, from the hours between 8 A.M. and 6 P.M. local clock.
- Use the nearest available Typical meteorological year data or an equivalent.
- Glazing Specifications must match the final building glazing schedule.
- Must include all permanent interior obstructions. Moveable furniture and partitions may be excluded.
- If existing, Glare-control devices must be included (ex. Blinds/Shades Operation, and Blinds/Shades Optical Properties).
- Set thresholds for the simulation to 300 lux for 50% of the annual occupied hours for sDA%, and 1000 lux for 250 hours of the annual occupied hours for ASE%.
In cove.tool the above parameters are met in the following manner:
- Follow the steps in the Geometry Requirements section.
- Change your grid size to 2 ft (6 m) on the bottom left-hand settings panel before beginning calculations. The analysis plane is automatically fixed at 30 inches about the floor objects.
- Period of Analysis is automatically fixed for annual occupied hours: January 1st to Dec 31st, 8 am to 6 pm local time.
- The weather file is based on your building location completed on the first page, which uses the latest and nearest TTY2 or TTMY 3 epw file from the DOE.
- Specify your glazing's visual transmittance using the Glazing VT% input
- Use the Interior Walls plugin category to import all interior obstructions to cove.tool. Doors and interior glazing may be excluded.
- Use the Shading Devices plugin category to import all physical exterior obstructions to cove.tool. This includes shades, overhangs, fins, frit and more. For other glare-control methods, the user can alter the Glazing VT% input to represent the shading strategies.
- Thresholds are automatically fixed to meet sDA (300 lux/50%) and ASE (1000 lux/250 hours).
After setting these parameters, proceed to run the simulations.
Step 2 - Run 3D Analysis
After uploading your building geometry, run the Spatial Daylight Autonomy (sDA) and Annual Sunlight Exposure (ASE) analysis in cove.tool. As the analysis completes, levels will load one-by-one with their % performance. If the percentages do not load at first, try refreshing your browser page. Before hitting the "Calculate" button, make sure your building is correctly placed and loaded (tutorial). Now lets set up the form for completing documentation.
Step 3 - In the Calculator, Identify each Space ID
Using the USGBC provide Daylight and Views Calculator, Begin by setting your LEED calculator to IP units. In the Daylight tab of the excel sheet, start listing the regularly occupied spaces in the building. Details of the Space ID, Space Description, and Total Regularly Occupied Area (sqft) should be sourced from the project drawings.
Step 4 - Analysis for sDA and ASE
Each level in the building geometry is analyzed by cove.tool for sDA and ASE.
The overall result for the analysis is shown in the top right-hand corner. LEED requires annual sDA value of atleast 55%, 75% or 90% demonstrated through annual computer simulations and an ASE of less than 10%. Next to the floors on the right, a percentage value is displayed for both sDA and ASE. Users can turn on one floor at a time to record the percentage value and save an image using the camera tool (in the top left corner). The legend in the right panel shows the PASS flag indicating the LEED passing range for each category separately.
Step 5 - Enter data for each floor level
Fill in the percentage values, for each level of the building, for both sDA and ASE. LEED requires a minimum of 55% sDA AND an ASE of no more than 10% to meet the criteria.
The points for sDA are awarded based on the table below.
Step 6 - Compile Documentation
Export Maps for each level, and compile into a single report. Submit along with calculator and narrative.
With this method, users will have used the cove.tool's Daylight analysis to document for LEED certification.
- What is the difference between Regular Regularly versus non-regularly occupied spaces?
A. According to the LEED BD+C v4.0 Handbook regularly occupied and non-regularly occupied spaces are determined the duration of the occupancy. Regularly occupied spaces are enclosed areas where people normally spend time, defined as more than one hour of continuous occupancy per person per day, on average. Occupied spaces that do not meet the definition of regularly occupied are non-regularly occupied; these are areas that people pass through or areas used an average of less than one hour per person per day. Example areas listed below (taken from the above link).