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Written By: Jennifer Wagner and Chelsea Code-McNeil 
Originally Published by ConcreteWorks May, 2016

Masonry is inherently a sustainable building material, thanks to its attributes contributing to resiliency- including project against rotting, mould and termites - that translates into lower maintenance costs and reduced need for virgin products. Further, its strength and ability to withstand severe weather and fire and helping meet new demands by designers for climate - resistant building materials, while its thermal mass benefits can reduce energy bills and improve indoor thermal comfort. 

Some concrete masonry uint (CMU) providers are looking for ways to introduce new elements of sustainability into their manufacturing practices, including use of carbon dioxide (Co2) recycling technology. This process involves retrofitting existing concrete plants with its technology that introduces carbon dioxide (CO2) gas sourced from the smokestacks of local industrial emitters into concrete during production. the CO2 gas undergoes a reaction whereby it becomes chemically converted int a calcium carbonate mineral. This mineralization not only permanently eliminates the CO2, but it also helps to make the concrete stronger, which enables concrete to become a powerful tool in the fight against climate change. 

Acknowledging the continually greener innovations within masonry manufacturing this article looks at how these Divisions 04 materials can contribute to points in the latest, forthcoming iteration of the U.S. Green Building Council's (USGBC's) Leadership in Energy and Environmental Design rating program, LEED v4.

Proponents of the LEED system say it has always made it a priority to propel and push industry to redefine what makes a material sustainable for manufacturers, designers, and building owners. The definition of what makes a building material green has evolved in the newest version, as LEEDv4 will take into account a broad range of considerations, including regional sourcing recycled content, and environmental impact over a product's lifecycle. 

Introducing LEED v4

LEED v4 will take a more holistic approach defining a green building material with a  particular focus on lifecycle impacts and supply chain management, taking the program's scope one step deeper into the manufacturing process. This change is expected to influence the information designers and architects are requesting from manufacturers. Architects are requiring more rigorous information from manufacturers, by asking them to collect information from outside their localized manufacturing processes.

In the past, self-declared recycled content and bare-bones regional declarations were enough to meet credit requirements, but under LEEDv4 this will no longer be the case. The information being requested will take time to collect, so manufacturers looking to stay ahead of the curve should start this process now during the transition period from the current 2009 version of LEEd to LEED v4, which comes into full effect on October 21., 2016.

Now that LEED is redefining what makes a material sustainable, less emphasis is being put on a product's individual attributes. This new emphasis is reflected in the redistribution of points in the Materials & Resouces (MR) credits. For example, under LEED 2009, six points (from three separate credits) could be awards for products with recycled (i.e. MRc4, Recycled Content), regional (i.e. MRc5, Regional Materials), or Forest Stewardship Council (FSC) content (i.e. MRc7, Certified Wood), whereas in LEEDv4 the individual attributes of recycled and FSC content are combined and "Regional materials" is not a separate credit,, but is rather introduced as a multiplier that applies to serval credits. 

LEED v4's MR category has two prerequisites (i.e. Storage and Collection of Recyclables and Construction and Demolition Waste Management Planning) and five credits. Three of those credits address different aspects of building product disclosure and optimization, ad are worth up to two points each. Those three credits which acknowledge a designer's use of sustainable products, are:

  • Building Product Disclosure and Optimization - Environmental Product Declarations;
  • Building Product Disclosure and Optimization - Sourcing  of Raw Materials;
  • Building Product Disclosure and Optimization - Material Ingredients;

The other two credits under LEED v4's MR category are:

  • Building Life-cycle Impact Reduction (worth up to five points, it encourages the adaptive reuse of materials or optimizes the environmental performance of products and materials); and 
  • Construction and Demolition Waste Management (up to two points).

According to LEED credit language the intent fo the three Building Product Disclosure and Optimization credits is "to encourage the use of products and materials for which life-cycle information is available and that have environmentally, economically, and socially preferable life-cycle impacts." Further, their intents is to reward project teams for selecting products according to specific criteria. For example, the Environmental Product Declaration credit calls for products "from manufacturers who have verified improved environmental life-cycle impacts," whereas the Sourcing of Raw Materials credit lauds materials "verified to have been extracted or sourced in a responsible manner.

Similarly, the material ingredient credit recognizes products "for which the chemical ingredients in the product are inventoried using an accepted methodology and for selecting products verified to minimize the use and generation of harmful substance. To reward raw materials manufacturers who product products verified to have improved life-cycle impacts."

So how do CMUs fit into all of this?

Environmental product declarations

The intention of Building Product Disclosure and Optimization -Environmental Product Declarations, is to encourage manufacturers to report and verify their products' lifecycle impacts. The best tool to communicate impacts over a products lifetime is a tool known as an environmental product declaration (EPD). EPDs that quantity the impact from the raw material supply, transport, and manufacturing stages are called 'cradle to gate', whereas those that go one step further to incorporate an en-of -life stage are called 'cradle-to-grave.'

In order to achieve this particular credit, project teams  have several options. one option is for project teams to use a minimum of 20 different permanently installed products from at least five manufacturers that have issued public declaration disclosing the environmental impact of these products. In other words, a single manufacture cannot contribute more than four EPDS to the total 20 that re required. 

Each of the 20 must be unique - that is, the purchased finished product has a unique function, or is mad by a different manufacturer. For example, tow CMU's created by the same manufacturer with the only difference being their color would not be considered unique materials; thus only one EPD would be able to count towards the required 20.

The most common method to comply with this credit is for manufacturers to issue product-specific ISO-compliant, cradle-to-gate EPDs, or to use industry-wide generic EPDs. Industry-wide EPDs are valued at half value for credit calculation purposes, since product-specific EPDs are considered to be more reflective of an actual product’s environmental impact.

The credit requires project teams to comply with one of a list of criteria for 50 percent – by - cost of the permanently installed products on the project. One option is to demonstrate that products have environmental impacts lower than industry averages in at least three of the following categories:

  • global warming potential (greenhouse gases);
  • depletion of the stratospheric ozone layer;
  • acidification of land and water sources;
  • eutrophication;
  • formation of tropospheric ozone;
  • or depletion of nonrenewable energy resources;

For this credit, some CMU manufacturers can issue EPDs for products made with recycled CO2 using proprietary technology that also reduces GHGs associated with manufacturing processes.

Sourcing of raw materials

There are two opportunities to achieve the “Building Product Disclosure and Optimization - Sourcing of Raw Materials”. The first option is for manufacturers to publish a raw material source and extraction report, and the second is for the manufacturer to engage in sustainable leadership extraction practices. This is the credit that captures many of the credits from LEED 2009, such as recycled content and certified wood.

In Option 1, a raw material source and extraction report can be provided by either the raw material supplier or the manufacturer themselves. The report must outline raw material supplier extraction locations and describe supplier’s commitments to:

  • long-term ecologically responsible land use;
  • reducing environmental harms from extraction and/or manufacturing processes;
  • meeting applicable standards or programs voluntarily that address responsible sourcing criteria;

The project team must have a minimum of 20 permanently installed products from at least five manufacturers that have publicly issued these reports. Third-party verified CSR reports which comply with a set of approved frameworks such as the Global Reporting Initiative (GRI) Sustainability Report are preferred (these reports contribute full value to the credit calculations), but self-declared reports are also acceptable (these reports provide half value).

The most common framework for creating these reports is that which is set out by the GRI, which has a framework outlining what needs to be included in the report in the environmental and social categories. The last category has several sub-categories: labor practices and decent work, human rights, social and product responsibility. It’s interesting to note that no manufacturer has chosen to publicly issue one of these reports to date.  

In Option 2,  the manufacturer to engage in sustainable leadership extraction practices. The credit requires that project teams meet one of the recommended responsible extraction criteria for at least 25% of the permanently installed products in the building, by cost. Acceptable responsible extraction criteria include recycled content, FSC certifications and materials reuse, which have requirements that appear relatively consistent from previous versions of LEED.

One of the new options for complying with the responsible extraction criteria is known as “extended producer responsibility” (EPR), also known as “product take-back”. This involves taking products at the end of their useful life and recycling them into the same product in a “closed loop” system. There are currently EPRs available for some products, including carpeting. Currently this credit option is difficult for project teams to achieve because there are a limited number of products with EPRs, and products meeting this criteria for this credit are valued at 50 percent of their cost.

To meet this credit of responsible extraction practices, some CMU manufacturers provide products with recycled content to projects. The recycled content credit is calculated in the same way as it was in LEED 2009 - that is, the sum of post consumer recycled content. The credit states products meeting the recycled content criteria are valued at 100 percent of their cost in credit calculations.

Material ingredients

There are three options to achieve the “Building Product Disclosure and Optimization – Material Ingredients” credit, but only the first two options are viable today. The first option is around material ingredient reporting. Projects must use at least 20 different permanently installed products from at least five different manufacturers that use one of the approved programs to demonstrate the chemical inventory of the products. 

Acceptable approaches include products that have published Health Product Declarations (HPDs) in accordance with the HPD Open Standard or products that have been certified by Cradle to Cradle (C2C) (v2 Basic or v3 Bronze level). HPDs are transparency documents similar to EPDs, except that they disclose materials that may pose a health risk for either an end user or a person involved in the manufacturing of that product. To achieve this credit a single manufacturer can contribute up to four HPDs towards the 20 that are required.

A second option takes it to the next level of optimization where one point is awarded when products are used that document any product ingredient optimization that has occurred using various approved tools. Options of compliance include products that are certified under Cradle to Cradle (where v2 Platinum products are valued at 150% of cost for instance) and GreenScreen (where products can be valued at 150% of cost if they undergo a full GreenScreen Assessment).

The easiest way for masonry producers to contribute to this credit is by issuing HPDs or Cradle to Cradle certifications. An individual company can provide HPDs or C2C certifications for up to four products for a particular project, which is a significant portion of the 20 total documents required to collect the credit. If the products meet a certain set of criteria, such as local sourcing and the absence of the highest level of hazardous material, they may be eligible for additional points.

In the MR credit in previous versions of LEED, points were awarded to projects that sourced materials regionally; however this is no longer the case in LEED v4. In LEED v4, separate points are not awarded for sourcing materials regionally, but rather a “regional material multiplier” is applied to other categories to increase or decrease the value of the points in the credit calculations.

For each of the three “Building Product Disclosure and Optimization” credits the regional materials multiplier is applied in the same way. Products sourced within 100 miles (160 km) of the project site are valued at 200 percent of their cost in credit calculations. Another major change is that the regional material threshold has been reduced from 500 miles down to 100 miles.


As concrete masonry producers continue to promote sustainable manufacturing practices, they will seek out new opportunities to reduce the environmental impact of their products - implementing CarbonCure’s CO2 recycling technology is just the first step. With both EPDs and HPDs available for products made with CarbonCure’s technology from masonry producers across the US, architects can start asking for these documents to help them achieve credits and points on projects going after either LEED 2009 or LEED v4 certification.


  1. ISO Standards include 14045, Environmental Labels and Declarations - Type III Environmental Declaration: Principles and Procedures, 14040 Environmental Managment - Lifecycle Assessment: Principles and Framework, 14044, Environmental Management - Lifecycle Assessment: Requirements Guidelines, and 21930, Sustainability in Building Construction-Environmental Declaration of Building Products.
  2. Visit


Jennifer Wagner, MSc, MBA, LEED Green Associate, is the vice president of sustainability for CarbonCure Technologies, a company that retrofits concrete plants with a technology that recycles waste carbon dioxide into the building units. Experienced with carbon accounting, she is a member of the Health Product Declaration Manufacturers’ Advisory Panel. Wagner can be contacted via e-mail at

Chelsea Code-McNeil, LEED Green Associate, is CarbonCure’s sustainability coordinator, and works to reduce the carbon footprint of the concrete industry. Formerly a LEED coordinator for a prominent architectural firm, she is a member of the Health Product Declaration Manufacturers’ Advisory Panel. She can be reached at


Concrete masonry units (CMUs) are inherently green building materials. Masonry has many attributes that contribute to its resilience including protection against rotting, mold and fungus and resistance against termites. Greater resilience translates into lower maintenance costs and reduced virgin materials. CMU strength and ability to withstand severe weather and fire are helping to meet new demands by designers for climate-resistant building materials. Further, masonry's thermal mass benefits can reduce energy bills and improve thermal comfort in building. This article looks at the material with in the content of the LEEDv4 rating system.




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