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Product Transparency FAQs

As green building becomes the expectation rather than the exception, building owners are asking for evidence that their facilities are as friendly to occupants and to the environment as planned. While building product manufacturers have responded with more sustainable products, many are also taking steps to increase transparency around how those products are made and perform. In the last few years, glazing industry manufacturers have taken a lead in sharing information on sustainability of their products and processes. Now it’s up to glazing contractors to apply the right tools to help architects specify products that can maximize a building’s overall sustainable performance. 

What are the key terms to know?

LCA – Life Cycle Assessment:  An LCA is a comprehensive method for assessing the potential environmental impacts of a building product or material, from the first step of extracting raw materials through the manufacturing process, installation until final disposal. The completed assessment forms the basis of an Environmental Product Declaration or Health Product Declaration. 

EPD – Environmental Product Declaration: An EPD discloses the life cycle environmental performance of a product, based on the LCA. It verifies that all the information gathered during the LCA is transparent and accurate, and presents product information in a set format that allows for easy comparison across products.

HPD – Health Product Declaration: An HPD is a voluntary document that provides a consistent reporting format for disclosing the human health impact of a building product. It discloses the human health impact of a building product by looking at product content and associated health information for building products and materials. 

PCR – Product Category Rules: The PCR scopes and sets rules for conducting the LCA. The PCR ensures every company measures the impacts of a product in the same way. The PCR identifies the methodologies and required calculations for conducting an LCA. Having an industry body set agreed-upon rules ensures that data collection and reporting are consistent across manufacturers. This consistency is critical in ensuring designers, glazing contractors and building owners can make comparisons across products. 

A group of industry organizations—the National Glass Association, Insulating Glass Manufacturers Alliance, the American Architectural Manufacturers Association, and the Window and Door Manufacturers Association—have together developed PCRs that respectively outline the rules for assessing the environmental performance of flat glass products, processed glass and windows in order to create EPDs for specific glazing products. 

Who is asking for an EPD and HPD?

Green standards increasingly call for product transparency declarations. LEED v4 incentivizes the use of EPDs or HPDs by offering points for these disclosure documents under the Material and Resources credit. Additionally, the Well Building Standard recognizes HPDs in meeting the Material Transparency requirement.

Many leading architecture firms now require material disclosure for products prior to considering them for inclusion in their libraries and projects. Others give preference to products carrying HPDs or EPDs.

Building owners, such as corporations dedicated to sustainability and health care organizations, are beginning to seek evidence that building products contribute to their healthful missions.

What is the impact of glass products on the environment? 

There are a number of ways in which glass products impact the environment during manufacturing and disposal. This is the information that will be outlined in an LCA and, ultimately, EPD. The first step is to examine the manufacturing process itself through sale to the consumer (cradle-to-gate) or from manufacturing through disposal (cradle-to-grave).

Some of the impact assessed by LCAs includes:

  • The extraction of raw materials
  • Water and non-renewable energy use during manufacturing
  • Emissions to air and water
  • Global warming potential
  • Impact on ozone depletion
  • Potential for acidifying the environment
  • Smog creation
  • Contribution to climate change.

How is a product EPD developed? 

There are four steps for securing an EPD. 

  1. Perform an LCA study based on PCR.
  2. Compile information in the EPD reporting format outlined by ISO 14025.
  3. Have an ISO-approved Program Operator, such as ASTM International, UL or the International EPD System, verify information reported in the EPD for accuracy. 
  4. Register the EPD with an LCA program operator to publish. 

What is the difference between an industry-wide EPD and a product-specific EPD? 

EPDs can be developed either by a single company or by an industry group. 

Industry-wide EPDs may be developed by an industry association to provide a broad life cycle assessment of a product type. This generic EPD counts as one-half of a product for LEED v4 credit achievement calculations.

Product-specific EPDs are developed by a manufacturer to provide detailed life cycle assessments for individual products. A product-specific EPD counts as one whole product for purposes of LEED v4 credit achievement calculations.

How is an HPD developed? 

There are four steps to developing an HPD. 

  1. Set goals for the HPD’s use. This will dictate what information to collect and include. 
  2. Gather data on either product ingredients or components. The contents should be noted for products as delivered to the jobsite.
  3. Enter the data into the HPD Open Standard format, via the HPD Collaborative’s Builder or another tool. 
  4. Publish the HPD, making it available to customers directly or on HPD Collaborative’s Public Repository. 

Companies have the option to verify via a third party that an HPD fully complies with the HPD Open Standard established by the HPD Collaborative. 


Stephanie Miller

Stephanie Miller leads marketing and communications for Vetrotech Saint-Gobain in North America. She can be reached at