LCA Inputs and Impact Measures

Hello Yaya, 

You do not need to include the calculated energy usage for 60 years of both the proposed and baseline building, if expected energy use is same in baseline vs proposed. However base building and proposed building estimated annual energy use has to be reported (I guess this will take into consideration for energy use of calculated service life) if you are changing thermal mass (insulation) from base building to proposed building. Example: If base building has 0 square feet of insulation and if you plan to use 5,000 square feet of R-30 insulation in proposed building. There will be significant improvement in environmental impacts if the energy difference has not been considered. 

The LCA has to include complete every impact measures (Global Warming Potential, Acidification, Eutrophication, Ozone Depletion, Tropospheric Ozone, and Depletion of Non-Renewable Energy resources.)

Refer to this link for detail information: https://desk.zoho.eu/portal/oneclicklca/kb/articles/mrc1-v4-international-us-canada

Hope this helps! 

Created on January 1, 2015 Reference Guide Correction ID# 100001982

Under "System Boundary" bullet, replace "ISO 21930 section A-1 thru A-4, B-1 thru B-7, and C-1 thru C-4" with "EN 15804-2013 sections A-1 thru A-4, B-1 thru B-5, and C-1 thru C-4."

This 2015 addenda corrects the LCA system boundary excluding operational energy and water usage.

Hi Bipin,

I copied the explanation from One Click LCA (the page you cited) regarding changing insulation on the baseline and proposed building:
"Operating energy performance. The baseline and proposed buildings must meet EA Prerequisite Minimum Energy Performance by adhering to the requirements of ASHRAE 90.1–2010, Appendix G, Opaque Assemblies, Vertical Fenestration, Skylights, and Roof Solar Reflectance and Thermal Emittance sections, because comparing an energy-efficient proposed building with an underperforming baseline building will skew the results. Increasing wall mass or insulation unnecessarily in the baseline building to show dematerialization in the proposed building is not acceptable. Energy modeling for either building is not required for this credit."

You are not supposed to compare different insulation levels on this study. You might change the insulation type though.

Hello Dionisio, 

The wording says - " comparing an energy-efficient proposed building with an underperforming baseline building will skew the results. Increasing wall mass or insulation unnecessarily in the baseline building to show dematerialization in the proposed building is not acceptable." 

If you are performing LCA-Calculation for an energy efficient building or a net zero building, the proposed building will obviously have more insulation as compared to base building. In such case, you cannot increase wall mass or insulation in the baseline building. While the energy use of baseline vs proposed will be different. The project can document energy use in the LCA calculation for such cases. 

Correct me if I am wrong here. 

The LEED WBLCA credit is a MR credit and is intended to reward teams for using lower impact materials that deviate from “industry-standard” materials and practices, or that employ dematerialization or other material strategies to reduce embodied impacts.  The credit requires that the operational energy performance of the Proposed Building be the same as the Reference Building and meet levels of minimum energy performance.

From the Reference Guide:

“Functional equivalence: The proposed and baseline buildings have to serve the same function and must have the same gross floor area, orientation, and operational energy usage.”

Any energy improvements that the Proposed Building has beyond reference performance will be awarded LEED points in the EA credit.  For the case of a WBLCA for a net zero building the envelope, including level of insulation, of both the Baseline and Proposed Buildings should be such that the buildings have the same energy performance.  In such a case where you are using a large amount of insulation the LCA will illuminate the impact of insulation. It could be a prudent LCA strategy to then investigate if there is a lower impact wall assembly that still provides equivalent energy performance.