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Emerging Best Practices for Special Conditions

The HPD Collaborative recognizes that there are practical limitations to disclosure. For some types of materials, the ability to identify and characterize substances and/or CAS RNs may be challenging. In other cases there are specific issues relating to hazard screening using CAS RN. The HPD Open Standard includes specific guidelines, or “Special Conditions,” to address these known issues.

Because the collective understanding about these materials and substances is rapidly evolving, guidance related to Special Conditions is documented on HPDC’s website as Emerging Best Practices as the guidance is developed. These policies are also harmonized with other material health programs such as Cradle to Cradle Certified, GreenScreen, and Declare. Maintaining harmonization with these and other programs is another reason these Special Conditions may be updated.

There may be updates to these Special Conditions, and additional material and substance types may be added to this online area, between releases of future versions of the HPD Open Standard. Therefore, it is important to review this information when creating an HPD, and if any Special Conditions are applicable.

HPDC has published guidance covering the following Special Conditions, which can be found below:

  • Biological Materials
  • Geological Materials
  • Mixed Recycled Content
  • Electronics
  • Form-specific hazards
  • Minor Fasteners
  • Metal alloys

HPDC is currently developing guidance for the following Special Conditions:

  • Float glass
  • Ceramics
  • Reaction products
  • Material with CAS RN but no specific molecular structure
  • Polymeric materials

The HPD Open Standard only allows Special Conditions exceptions to be used for approved Special Conditions, as listed here. For other classes of materials, including those listed for which guidance is under development, manufacturers must use the typical HPD methods to complete HPDs.

As Special Conditions are updated, and new Special Conditions are developed, they will be posted here, and enabled in the HPD Builder and other HPD-Open-Standard-compliant tools. Please contact HPDC with questions, suggestions, or comments on these policies.

Scope of Special Conditions Guidance

Special Conditions guidance specifically addresses the reporting requirements that are different for the classes of materials discussed here, and in the specific ways specified in these documents. Unless otherwise specified, all other reporting requirements for these materials are consistent with the typical requirements in the current version of the HPD Open Standard.

LEED v4 relevance

HPDC has developed these Special Conditions with LEED compliance in mind. When Special Conditions guidance is used in completing an HPD, it will be indicated, and will not generally interfere with LEED compliance. For more details, see HPDC’s guidance to LEED v4 compliance.

Version control nomenclature

When guidance is established or revised for a Special Condition, a version nomenclature with date is provided. This nomenclature is independent of the current HPD Open Standard version, and must be referenced in the Material Notes field of the HPD. When updating an HPD, the most current guidance must be used, and referenced. (HPD-Open-Standard-compliant tools such as the HPD Builder will handle this automatically.)

Biological Materials SCBioMats/2023-07-20





Form-Specific Hazards SCFormSpecific/2023-07-20


Geological Materials



Metal Alloys SCMetalAlloy/2023-07-20


Minor Fasteners



Mixed Recycled Content SC MixedRC/2023-07-20






Special Conditions “How-To” Videos