One of the biggest challenges to assessing the embodied carbon of structural systems is access to collecting data. If we are in early stages of design, we probably don't know where our materials are coming from, or even how much steel tonnage will be in the building. To address the inherent uncertainty that comes with performing LCAs, there are four data collection strategies. 1. **Measuring**: Quantities can be directly measured from bills of materials, or physical quantities (e.g., contractor submittals or procurement records). 2. **Modeling**: Quantities can be modeled (e.g., analytical structural model, structural Revit model, typical bay calculations). 3. **Researching**: Typical quantities or data may be available for systems of inputs (e.g., recycling rates, transportation impacts, typical structural system values). 4. **Estimating**: Quantities may need to be estimated based on judgment or experience for material quantities (e.g., non-modeled quantities, replacement scenarios, construction waste rates. The preference for each strategy is to: (1) measure, (2) model, (3) research, and (4) estimate (top to bottom). Each data collection strategy has its time and place within an embodied carbon assessment. For some structural components, it may be possible to measure. For others, it may require an estimate. It is often left to the engineer to identify which strategy is the most effective. The forthcoming [[Prestandard for Assessing the Embodied Carbon of Structural Systems for Buildings]] will provide further guidance for collecting data. # Navigation Return: [[Home]] Suggested Next: [[Environmental Product Declarations (A1-A3)]]