Understanding HPDs - Key Concepts

How the HPD is structured

The HPD Open Standard defines six sections for the HPD: 

• Section 1: Summary – highlights the contents of the product and their hazards, as well as key reporting elements such as thresholds 
• Section 2: Content in Descending Order of Quantity – this inventory is the heart of the HPD; it lists contents in the product, their associated hazards, and other relevant information
• Section 3: Certifications and Compliance – for example, certifications for VOC content and emissions 
• Section 4: Accessories – for example, what’s needed to install or maintain the product 
• Section 5: General Notes – for example, explanations from the manufacturer 
• Section 6: References – for example, links to hazard lists used in the HPD

The HPD Open Standard (http://www.hpd-collaborative.org/hpd-2-2-standard/) includes both a Format and detailed Instructions for each data element included in the Format. It also includes a glossary. While primarily oriented toward those creating an HPD (product manufacturers), the Instructions can also be very helpful as a reference for project teams, providing a detailed technical specification for what each data element of an HPD includes.

There are three key concepts underlying the HPD Open Standard that project team members will find useful in working with HPDs: 

• Content inventory, including definitions of contents (materials and substances), thresholds, and content inventory methods 
• Descriptors of the completeness and type of reporting – characterized, screened, and identified 
• Hazard screening – GreenScreen® for Safer Chemicals scores

These concepts are introduced in the following section. More detail on these concepts, as well as further explanation of each section of the HPD, is included in Chapter 4 of this Guide.

Content inventory

Introduction to content inventory

The content inventory lists contents in the product as well as the thresholds established for their reporting, hazard screening information, and other relevant information. Within the HPD this information is summarized in Section 1, which is always the first page of an HPD. Details of the content inventory are reported in Section 2, which begins on page 2 of the HPD, and continues for the number of pages required to report the complete information.

HPD v2.1 revised the methods that can be used to create a Content Inventory, based on requirements for achieving the LEED v4 Material Ingredients credit with HPD v2. The methods for creating a content inventory are based on how contents are categorized (for the entire product or for each of the materials that comprise the product) and how reporting thresholds are applied (a single threshold for the entire product or individual thresholds for each material). The creator of the HPD, the product manufacturer (or, on behalf of the manufacturer, a third- party preparer) determines which of these content inventory reporting methods is used in a given HPD. 

• Nested Materials Inventory Method: contents are reported first at the materials level. Substances are then itemized within each material. If a substance appears in multiple materials, it will be listed multiple times in the inventory, appearing under each material where it is a constituent. 
  • Nested Materials Inventory with material-level thresholds. In this method, thresholds are established for each material and these thresholds govern which substances must be listed under each material.
  • Nested Materials Inventory with product-level threshold. In this method, a single threshold is established for the product and is used to determine which substances are listed under the various materials. 
• Basic Inventory Method: contents are reported only at the substance level, regardless of the material structure of the product. A product-level threshold must be used.

A Nested Materials Inventory provides useful information about the structure of the product, and groups the substances within their respective materials. This additional information facilitates improvement and innovation of the product. All three of these methods can be used to meet LEED requirements. The details of these reporting methods are further explained later in this chapter.

Contents: materials and substances

A product’s contents can include the materials and itemized substances that comprise each material: 

• Material. A “material” is a uniform solid, liquid, or gas. Materials are composed of one or more “substances.”
• Substance. A “substance” is matter that can be characterized by the entities that comprise it (molecules, atoms, etc.) and by its physical properties, such as density, refractive index, electric conductivity, melting point, etc. 
• Content. The word “content” is used in the HPD Open Standard to refer to both materials and substances more generally, and to refer to materials and substances together.

Most products are composed of one or more materials, and materials are composed of one or more substances. As illustrated below in Figure 4, products can be composed of just a few materials or can be very complex, involving numerous materials and extensive supply chains:

Threshold

“Threshold” is key to understanding the precision of reporting used in the HPD (and its ability to comply with LEED, Cradle to Cradle, and other programs). The threshold is the amount or concentration of a substance that must be present for that substance to be reported, at the specified threshold level.

A lower threshold means that smaller amounts of substances will be reportable and therefore disclosure will be more complete. There are several ways thresholds can be reported: 

• Parts per million (ppm) in which a threshold of 100 ppm is more stringent and requires reporting of substances present at lower concentrations than a threshold of 1,000 ppm, and hence is likely to lead to disclosure of more substances. Note that concentrations can also be expressed as percentages, with 100 ppm = 0.01%, 1,000 ppm = 0.1%, and 10,000 ppm = 1.0%. 
• Safety Data Sheet (SDS), based on the Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. The SDS requires content reporting at 1,000 ppm (0.1%) only for reproductive toxicants, carcinogens, and category 1 mutagens, and at 10,000 ppm (1%) for all other hazard categories. The SDS is required to report certain hazardous contents that will be handled by workers in factories and does not require reporting of all substances.

Thresholds can apply to the whole product or to each material in the product. If thresholds are reported for each material, the summary can include several different thresholds; for example, 1,000 ppm for some materials and 100 ppm for others.

Content inventory methods

The methods that can be used to report the contents in a product, “Nested Materials Inventory” and “Basic Inventory,” are further explained in this section.

• “Nested Materials” Inventory method. This method lists all materials in the product. All substances within each material that are above the threshold level specified are itemized under that material – hence, the inventory has a “nested” structure. As described above, there are two variations of this Inventory, based on the way the threshold is specified – at the material level or at the product level. 
  • If material-level thresholds are used, they will be indicated in the Threshold data field for each material. 
  • If a product-level threshold is used for a Nested Materials Inventory, reporting is based on the following:
    • A material-level threshold may be used for selected individual materials to provide additional information where it is available and the manufacturer chooses to disclose it (i.e., the actual threshold used to identify substances for that material). All substances above that threshold in the material are listed, not just the subset of substances that are above the product-level threshold established for the entire product.
    • For any material where the product-level threshold is used, only those substances that are present at or above the product-level threshold are reported, “Other” is indicated as the threshold for the material.
    • It is possible that a material can be listed with no substances nested under it. This could occur if all substances in the material are below the product-level threshold indicated. “Other” is indicated as the threshold for any such material. 
• “Basic” Inventory method. This method does not identify materials and creates a single list of all substances within the product based on a product-level threshold.

See illustration that follows:

Examples of HPDs created with these different methods are provided on the HPDC website (http://www.hpdcollaborative.org/sample-hpds/).

The Nested Materials Inventory method offers a number of advantages: 

• Managing content data by material rather than by product allows suppliers to provide data to final manufacturers about discrete materials in the supply chain for use in a final product HPD. Suppliers can update that information as their supplied materials change. Manufacturers can produce HPDs on different products simply by assembling the appropriate material inventories from suppliers, without having to rebuild HPDs from scratch for each variation or update. 
• Suppliers can provide inventory threshold information without having to know the different specific concentrations of their material in the final products. 
• This material-based format allows the HPD to support other programs, such as Cradle to Cradle, which evaluate thresholds of concern on a material basis rather than a product basis. 
• It enables manufacturers and project teams to identify the specific material(s) containing the listed hazards; this is a first step toward reducing or eliminating the hazard and developing an improved product. 
• It informs discussions between manufacturers and project teams about the role of the material and the potential for finding less hazardous alternatives. 
• It more closely matches manufacturers’ ordering systems and databases. 
• It encourages reporting of substances at finer detail.

Descriptors of the completeness and type of reporting

Characterized, Screened, Identified

This section summarizes the completeness and type of reporting in the HPD. 

• “Characterized” indicates whether the percent weight (quantity) and role or function are provided for all substances above the threshold indicated. 
• “Screened” indicates whether all substances above the threshold were screened for hazards using lists in the HPD Open Standard, and results are reported. 
• “Identified” indicates whether all substances above the threshold are reported by name and identifier (Chemical Abstract Service Registration Number – CAS RN).

You may encounter situations where a manufacturer has not “Identified” one or more substances but still has “Characterized” and “Screened” them. This reporting approach provides a way to withhold disclosure of proprietary information but still report information about potential hazards associated with the product contents. Such reporting would provide for compliance with certification requirements, such as for the LEED v4 Material Ingredients credit.

“Yes Ex/SC” means that the requirements to Characterize, Screen, and/or Identify have been met using HPDC-approved Special Conditions guidance for specific classes of materials. This indicates compliance with LEED v4, but through a different pathway in the HPD reporting methodology.

Hazard Screening and Assessment

Pharos Chemical and Materials Library and GreenScreen® for Safer Chemicals scores

An integral element of reporting about products with the HPD Open Standard is to include a hazard screening of the substances in the product and a listing of hazards that have been associated with these substances. This association information has been determined by many different, independent authoritative bodies, based on criteria that they have established using the results of epidemiological, toxicological, and scientific research studies. The HPD Open Standard specifies which of the lists created by these authoritative bodies are to be considered in the hazard screening information reported in an HPD (see Appendices B–F of the HPD Open Standard for further information on the authoritative bodies and hazard lists. Appendix E, HPD Priority List Warnings is now on the HPDC website, not in the Standard document, due to length; see https:// www.hpd-collaborative.org/hpd-2-2-standard/).

A screening result that indicates an association of a substance with a hazard does not provide information about the exposure to or risk of that hazard in the product. Determination of exposure and risk requires additional assessment of the product. Obtaining hazard screening information is a necessary first step in creating exposure and risk assessments, so it is important information to be reported in an HPD. It is also required information for meeting the LEED v4 Material Ingredients credit requirements.

For the HPD Open Standard, Hazard Screening is performed using the HPD Open Standard Priority Lists. These lists are primarily based on the GreenScreen® for Safer Chemicals, a program of the nonprofit organization Clean Production Action, but also include lists from the U.S. Environmental Protection Agency, the European Union, and other governmental organizations. Typically, the hazard screening results that are reported in an HPD will be produced using the HPD Builder tool. Within the Builder tool, the hazard screening is automated through the use of the Pharos database, which is created and maintained by the Healthy Building Network. It is also possible for this screening to be performed if an HPD has not been created using the HPD Builder tool, but it is very difficult to conduct an accurate hazard screening without the use of the HPD Builder or another automated tool. If the HPD does not indicate that it was created using the HPD Builder tool (this reference will appear in the upper right hand corner of the HPD Summary page) then you should inquire to verify that a proper hazard screening was conducted. If an HPD has been third-party-verified, the third party will have verified this information.

The GreenScreen approach, as implemented using the Pharos database, facilitates comparative chemical hazard screening and assessment at the substance level. There are two types of GreenScreen results that can be reported in an HPD: 

• List Translator(LT) scores: these are produced through an automated tool that screens against hazard lists specified in the HPD Open Standard. No assessment is performed. For more information on the GreenScreen List Translator™: http:// www.greenscreenchemicals.org/method/greenscreen-listtranslator 
• Benchmark (BM) scores: these are produced through a Certified Full GreenScreen Method assessment that includes a toxicological review of all available information from scientific studies, hazard lists, and modeling or analogs. For more information on the Full GreenScreen Method: http://www. greenscreenchemicals.org/method/full-greenscreen-method

Benchmark scores represent a more comprehensive assessment than List Translator scores.

In addition to the complete list of identified hazards, the HPD hazard screening summary includes two summary indicators based on GreenScreen results for substances that are included on GreenScreen lists (substances from other lists are indicated as UNK (unknown): 

• Number of GreenScreen BM-3/BM-4 Contents. This section reports on the total number of substances with lower hazards – Benchmark 3 (use but there’s still opportunity for improvement) or Benchmark 4 (prefer – safer chemical). 
• Contents’ highest concern GreenScreen Benchmark or List Translator Score. This section reports on the most hazardous GreenScreen List Translator or Benchmark score found in any of the substances in the product.

Additional information on these concepts and other data in the HPD is presented in Chapter 4 of this Guide.

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