The analysis.tool assists users in pursuing the following BD+C LEED v4.0 credits:
IP c1 - Integrative Process
SS c1 - Site Assessment
EA p2, EA c2 - Minimum Energy Performance & Optimized Energy Performance
IEQ p1 - Minimum Indoor Air Quality Performance
IEQ c7 - Daylight
IEQ c8 - Quality Views
WE p1, WE c1 - Outdoor Water Use Reduction
LT c4 - Surrounding Density and Diverse Uses
Pilot Credits MRpc 132 - Procurement of low carbon construction materials
Before we begin, here are how credits have changed in Beta version 4.1. Until v4.1 is fully adopted, analysis.tool will continue using v4.0 BD+C Reference Guide as the default standard for calculation methodologies and compliance thresholds.
IP c1 - Minor changes: the Integrative Process Worksheet is replaced by the Project Team Letter which asses additional strategies beyond Energy and Water-Related Systems. Additional assessments for site selection can be modeled in analysis.tool using the 3D analysis page.
SS c1 - Minor changes are irrelevant to analysis.tool support.
EA p2, EA c2 - Major changes: a new greenhouse gas emissions metric has been added to determine optimized energy performance. The threshold for the number of points earned by energy reduction percentage has also been shifted (review here). Last, the baseline prescriptive model to calculate %reduction now follows ASHRAE 90.1-2016 (v4.0 uses 90.1-2010).
IEQ c7 - Minor changes: 1 Point is earned for 40% sDA. A narrative can be provided to address glare for any space over 10% ASE (previously only possible up to 20% ASE).
IEQ c8 - Minor changes: Auditoriums, conference rooms dedicated to video conferencing, and gymnasiums may be now excluded from regularly occupied spaces for this credit. The view type requirements were also revised to eliminate potentially redundant requirements or unachievable view access. Now designers must have just 75% of the floor area have view access to nature, urban landmarks or art, or objects at least 25 feet (7.5 meters) from the exterior.
WE p2, WE c2 - No changes.
WE p1, WE c1 - Minor changes are irrelevant to analysis.tool support.
LT c4 - Minor changes are irrelevant to analysis.tool support.
Pilot Credits MRpc 132 - No changes.
LET'S BEGIN
IP c1 - Integrative Process Credit
analysis.tool can be used as one method to demonstrate energy and water-related preliminary studies required in the Integrative Process Credit, as seen above in a table displaying required studies and where inside the web app the data can be found. To see how to document LEED’s Integrative Process Credit, check out this article. analysis.tool was designed to be an early stage performance evaluation tool, and therefore meant to reoccur throughout the design phases and quickly test various building, design, and system combinations. With analysis.tool, users can archive their projects at each stage and document the evolution of the decisions made throughout SD, DD, and even CD. Thus a quick and organized framework for the LEED process.
SS c1 - Site Assessment
analysis.tool can be used as one method to demonstrate climate and human-use related studies required in the Integrative Process Credit. The auto-generated PDF report comes complete with a climate profile of your building location. Climate studies include diagrams on relative temperature and relative humidity, solar exposure and beneficial radiation, a psychrometric chart with passive strategy breakdown, and monthly wind analysis. Download a site assessment worksheet from USGBC here, to get started. The Human Use component can be initiated using carbon emission results and site activity opportunities using the bike/walk/transit score.
LT c4 - Surrounding Density and Diverse Uses
analysis.tool allows users to access data needed to document the LEED v4.0 LT c4 Surrounding density and diverse uses credit. Although analysis.tool does not yet generate a list of the context buildings, all the data needed is readily available. Users can access surrounding context buildings and embedded Property Line data.
analysis.tool automatically generates context data for approximately 1 mile around the project's specific location. The context map, buildings, and property lines are sourced from MapBox. All of these can be toggled on/off easily to navigate the map. Each plotline information about the Site address (location), Land Use Class (residential or non-residential), Building area (sqft) or Gross Floor Area, and Deeded acreage i.e. Buildable Land Area (acres). These values can further be used to calculate the Combined Density (sqft/acre) and Floor Area Density or FAR.
EA p2, c2 - Minimum Energy Performance, & Optimize Energy Performance
These credits require a whole building energy simulation for credit compliance. In this circumstance, analysis.tool cannot be used to directly earn the LEED points. Instead analysis.tool estimates the preliminary number of points that could be achieved if you were to use similar bundles created in analysis.tool with further staged energy simulation tools. Since LEED requires a whole building energy simulation to establish a baseline energy target, analysis.tool accomplishes a similar feat by calculating its own energy baseline according to the ASHRAE Standard 90.1 - 2010 (more on this here). Using the ISO 13790 Heat Balance Engine, prescriptive inputs from your selected energy code, industry-standard assumptions based on your building type selection, and the most local and recent climate data (weather file), analysis.tool calculates Baseline EUI, EUI breakdown, and EUI target. This methodology was tested and calibrated to be within 3-5% of EnergyPlus, so it's accurate and a great approach to quickly generate feedback about energy, water, carbon, and daylight performance for your design. For the possible 18 points available, analysis.tool estimates the preliminary number of points that could be achieved for this design, see the table below for the point range.
From here analysis.tool can optimize the percentage improvement made possible through each mechanical system and product selection to determine a better performing energy improvement bundle and maximize the number of LEED points that can be achieved.
IEQ c7 - Daylight
analysis.tool's daylight simulation method follows the guidelines required of the BD+C LEED v4.0 IEQ - Daylight credit for sDA% and ASE% simulations. However, buildings with dynamic facades can not pursue LEED compliance with analysis.tool, as that is currently not a capability inside the web app. In order to set up a LEED-compliant simulation,
You can bring in your geometry to drawing.tool and assign occupied and unoccupied rooms within the platform. In this case, the platform generates an automated LEED Daylight report as well. Read more about it here.
When drawing.tool is skipped, the user must denote unoccupied areas from the floor plate during upload. That means occupied spaces can be uploaded regularly as Floor objects, and unoccupied areas should be uploaded through the Shading Device Layer. Read more about the Daylight tool here.
Once this process is complete, users should not use this project for energy results as analysis.tool uses geometry uploads to calculate energy-related inputs and results (ex. Occupant Density, appliance use, and more).
Other important Daylight details for LEED compliance is listed below.
We are using a Tregenza sky with 145 subdivisions.
To speed up the simulation we are keeping the reflectivity fixed for now with the following assumptions: Floors 40%, Interior Walls 70%, Ceiling 70%, Exterior Facade 35%, and Walls 35%. Glazing VT% is user-defined and can be changed at any point to reflect end-use conditions. This allows any user to construct a realistic simulation and avoids "cheating" the simulation with incorrect inputs
sDA (Spatial Daylight Autonomy) - requires a 50% sDA to pass. The calculation method is 300 lux/50% of the annual occupied hours (8am-6pm) on the horizontal work plane.
ASE (Annual Sunlight Exposure) - requires a <10% ASE to pass, or <20% ASE to pass with a narrative on reducing ASE. The calculation method for ASE is 1000 Lux/250 occupied hours (8am-6pm) on the horizontal work plane.
You can find a tutorial for detailed daylight documentation here.
IEQ c8 - Quality Views
analysis.tool analyzes your building's configuration for 3 types of quality views. These analysis types are taken from the LEED v4.0 IEQ c7 Quality Views Credit type 1-3 and a total quality view count. Users must identify regularly occupied floor areas and run the 3D analysis for those spaces.
Taken from "LEED v4.0 - IEQ c7 Quality Views" Credit, the Quality Views Assessment is a grid-based analysis. First, each floor of the analyzed building is divided into 1-foot x 1-foot grid cells. Then, from the center of each grid cell, the presence of obstructions is checked in all directions, namely, walls, windows, and furniture. If a window is present without obstruction, the distance from the grid center to the obstruction is determined, and this information is used in calculating the different LEED Views Scores for that grid cell. There are three different scores calculated to determine four different view types for each grid cell:
Sight Lines: If there are two windows present in the line of sight from the center of this grid cell in any two directions, such that the directions are at least 90 degrees apart, a positive ‘Type 1’ score is assigned to this grid cell.
Sky and Context: If there is a window present in the line of sight from the center of this grid cell this analysis checks two lines of sight through the window. In the horizontal light of sight, if no context building or building element exists at least 25 ft beyond the window, this analysis is partially satisfied.
The second part of this analysis checks along an oblique line of sight from the grid cell center when looking toward the top of the window. If there is no context building or building element at least 25 ft beyond the window, this analysis is completely satisfied and a positive ‘Type 2’ score is assigned to this grid cell.Unobstructed View: If from the grid center there is a window in direct line of sight within the distance that is at most three times the maximum height of the window itself from the floor, the grid cell is assigned a ‘Type 3’ positive score.
Total Quality Views: If at least two of the above conditions are satisfied then the grid cell is assigned a positive ‘Merged Views’ Score.
After the Quality Views Score has been calculated for each grid cell comprising the floor, the scores are assigned a color to generate a heatmap. The purpose of this heatmap is to provide a visual representation of the view's effectiveness for the entire assessment of each view type.
The Irrigation/Outdoor Water Use calculation method follows (BD+C) LEED v4.0 WE p2,c2 - Indoor Water Use Reduction credit. Using the 5 Fixture Categories, and building floor area, analysis.tool will calculate the difference between the water use of baseline fixture flow rates and low flow rates to determine indoor water use reduction. The LEED rating systems for indoor water use reduction are on a 1 to 6-point scale and based on a %reduction threshold, the table below.
WE p1, WE c1 - Outdoor Water Use Reduction
The Irrigation/Outdoor Water Use calculation method follows (BD+C) LEED v4.0 WE p1,c1 - Outdoor Water Use Reduction credit. By default, all projects begin with a baseline template for a turf-based irrigation setup. As users start to alter the baseline assumptions and customize their outdoor water use plan, Total Irrigation Water Use will increase or decrease. The difference between a baseline turf-based irrigation plan and your custom plan will calculate the water use reduction. The LEED rating systems for outdoor water calculation are simple: No irrigation or 100% outdoor water use reduction is 2 LEED points and 1 point for 50% outdoor water use reduction.
For more information about analysis.tool and LEED credits check out these articles:
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