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Emerging Best Practices for Consideration of Residuals and Impurities


Consideration of Residuals and Impurities is a topic covered by Emerging Best Practices, within the HPD Open Standard.  The HPD Open Standard 2.0 revised the way Residuals and Impurities are handled in the HPD; the requirements in HPD 1.0 were found to be too onerous and not feasible for many manufacturers, products, and processes.  HPD Open Standard v2.1.1 (Released 7/2/2018; Effective Date September 2018) does not introduce any changes to the guidance on Consideration of Residuals and Impurities.

Emerging Best Practices supplement the information and requirements presented in the HPD Open Standard Instructions and Format, as an official element of the HPD Open Standard.  For additional information about how Emerging Best Practices are governed as part of the HPD Open Standard, visit the Emerging Best Practices Landing Page by clicking on this link.

The HPD Open Standard v2.1 (unchanged in v2.1.1) states:  Residuals/Impurities

Indication of whether residuals and impurities are considered for the material and included in the inventory. Options are either “Considered” or “Not Considered”.

When Residuals/Impurities are “Considered,” the manufacturer has taken steps – such as those outlined in Emerging Best Practices – to understand what residuals and impurities may be present in the material and disclose that information on the HPD. The term “Considered” is used, rather than “Included,” to address currently unavoidable variability in methodology and rigor due to industry sector differences in knowledge about residuals and impurities in materials used. Guidance related to considering, identifying and quantifying residuals and impurities is documented on the HPD Collaborative website as Emerging Best Practices (emphasis added).

Please follow the links shown below to access the current versions of Residuals/Impurities guidance.  If you have need further information or have questions about Emerging Best Practices for Consideration of Residuals and Impurities, please contact us at

Residuals and Impurities Emerging Best Practices Documents Effective Date Weblink to Access Documents

Best Practices for Residuals and Impurities – Text

v2.1 – 10-02-2017

Residuals and Impurities – One Page Graphic

v2.1 – 10-01-2017

Residuals and Impurities – Step-by-Step Process Graphic

v2.1 – 10-01-2017