The purpose of the LEED v4 BD+C MRc1 Building Life-Cycle Impact Reduction, Option 4 credit is to conduct a life cycle assessment of the project’s structure and enclosure to show a minimum of 10% reduction in building material life cycle impacts compared to a baseline in at least 3 different impact categories, with global warming potential being one of those as a mandatory requirement. No impact category assessed as part of the life-cycle assessment may increase by more than 5% compared with the baseline building. If the design team can improve in all 6 categories, they will get the additional exemplary credit.

This guidance applies to the following One Click LCA tools:

This guidance is planned to be used along with the credit reporting template, which you can find as a downloadable attachment at the bottom of this page, in addition to an example report. The template reports can be filled in and submitted for LEED LCA credits:

The MRc1 credit option 4 is suitable for new construction (buildings or portions of buildings).

In life cycle assessment projects, the potential to cause environmental harm is assessed over the project’s whole lifetime for specified environmental impacts. Building service life for LEED is estimated to be at least 60 years for all building types; in One Click LCA you will need to enter the calculation period for your building.

In LEED, the life cycle assessment is done for six different environmental impact categories. Below are the LCA impact categories for LEED LCA and their descriptions:

The LEED tool reports stages A1-A3, A4, B3, B4-B5 and C1-C4.

In LEED v4 CML, TRACI and ReCiPe methodologies are accepted. Out of these methods, TRACI is commonly used in North America, and CML is required by the EN standard and is, therefore, de facto the required methodology in Europe and also widely used internationally.

Below is a chart summarizing how TRACI, CML and ReCiPe differ in showing calculations for the different impact categories.

One Click LCA supports both TRACI 2.1 and CML (2002 – November 2012 or newer). LEED tools for US and Canada support TRACI 2.1 methodology and the versions for Europe and international users support CML (2002 – November 2012 or newer). In One Click LCA all of the datasets follow ISO14044 standards and thus, the data is automatically compliant with the required standards and required impact assessment methodology.

The material scope required for LEED is specified in the following table. This includes the materials for the structure and the envelope. Out-of-scope materials may be included; however, adding them will not provide any extra credit.

As per LEED v4 specification, the following elements are excluded from the analysis: electrical and mechanical equipment and controls, plumbing fixtures, fire detection and alarm system fixtures, elevators, and conveying systems, excavation and other site development, and parking lots.

Create a building project and select the most relevant tool for your project:

"LCA for LEED, US (TRACI)"

"LCA for LEED, US (Canada)"

"LCA for LEED, Int'l (CML)"

Add all of the materials required by the calculation scope (see above). Fill in your project information in One Click LCA by entering the design either manually or by importing your data. A full list of supported integrations can be found here. If you need help finding the right datasets for your building materials, check our guidance pages on Material Selection & Resources.

You are allowed to use either average data, manufacturer-specific EPDs (recommended) or similar products from another manufacturer. Use net quantities (amounts of material installed in the building); the on-site losses of materials would be included in module A5, but that is excluded from the calculation by credit specification.

This information will be used to calculate the raw material harvesting, transportation and manufacturing impacts in A1-A3.

Once the materials and quantities are provided, set the transportation distances from the material manufacturer to the project site and the transport methods.

The default transportation distances can be set up from the project’s LCA parameters page. If they are chosen, any material will use the average distance unless a more specific one is given in the query. This information will be used to calculate the impacts of material transportation in A4.

This information will be used to calculate the material replacements for B4 impacts.

Material service life means how long each material will last in your building. If the service life is less than the service life of the building, the material will have to be replaced. From an environmental impacts point of view, this means additional emissions from the production of new material that is needed to replace the old one.

Each of the materials in the One Click LCA database has a default service life. However, as the exposure conditions of the materials may vary, it may be good to check that the service life matches the condition of your building. It is especially important to check the external wall and roof material service lives, as the weather conditions may vary greatly between areas.

Adjust the localisation of each material as needed (Expert feature). This information will be used to compensate for any material data chosen from another area to match your project’s local material manufacturing conditions.

This information will be used as a divider for the results in a separate result row and it will help you to understand how the results compare to other projects. The gross floor area is required.

This is the required service life of the building. LEED recommends a service life of at least 60 years. Product replacements and maintenance are calculated for this period.

After you have done one calculation, you can create as many additional designs as you wish, either by copying the first one or by creating a new empty one. This can be used for creating a baseline or to create additional 'what if' scenarios. To copy a design, click its name and choose 'Copy'. To create a new one, click the '+ Add a design' button on the project main page.

Once the Baseline design is completed, create a copy of it and name it 'Proposed design'.

To make sure that the baseline and proposed models can be accurately compared, the following aspects must be kept the same in both the baseline and the proposed building:

Other portions of the baseline building may be modified from the basic ASHRAE 90.1 requirements to capture the LCA goals of the project team.

As a summary:

You can read more on baseline strategies in our guidance article: LEED Baseline Strategies.