Author Archives: Walter

Declarable Substance List (DSL)

The IEC 62474 Declarable Substance List (DSL) is a list of regulated substances and substance groups (e.g. lead and lead compounds) that a manufacturer should declare to downstream manufacturers if present in the product. Each substance or substance group entry in the list is accompanied with a reportable application and a reporting threshold level. The supplier that is creating the material declaration will use this information to determine if the substance must be declared.

The DSL may be accessed from the IEC 62474 database via the menu bar on the left side of the introduction webpage – click on “Declarable substance groups and declarable substances” and then select the substance from the drop down list. For example, selecting “Lead/Lead Compounds” presents five entries with different reportable application / reporting threshold combinations – the first entry corresponds to the RoHS restriction. Clicking on the “Details” button reveals information about reference substances; typical EEE applications, regulations, and other information.

There is also an option on the website to export the entire DSL.

User Guidance document for IEC 62474

A user guidance document for the IEC 62474 materials declaration standard is in the works. The guidance, which will be designated IEC 62474-1, is being written by the original working group that developed IEC 62474. The expected publication date is late 2014. It will provide information on:

  • how to create a materials declaration in xml;
  • how to handle many complex (and sometimes confusing) declaration situations
  • examples of typical material declarations

How to declare a substance that belongs to two different substance groups in IEC 62474

A material declaration that conforms to IEC 62474 requires that a declared substance must be assigned to it’s respective substance group (if the substance group is declared in the material declaration). In most material declarations this is straightforward. However, there is a corner case emerging when a substance has two or more possible declarable substance groups that are reportable. For example, the REACH SVHC substance “Lead sulfochromate yellow” creates such a situation. The declarable substance groups “Lead/Lead Compounds” and “Chromium (VI) Compounds” are both relevant. Howevever, it’s not possible to have “Lead sulfochromate yellow” declaration assigned to both substance groups simultaneously in the XML file. This situation potentially creates a small amount of double reporting for users that roll-up the total content of specific substances/elements. The IEC 62474 standard is vague on how to deal with this.

Let’s look at this situation in more detail….

Subclause 4.2.3(a) states “… Such substances shall be assigned to the substance group (if the substance group has a mandatory reporting requirement) or otherwise to the product part (if 4.2.2 applies) or otherwise to the product.”. Subclause 4.3.4(a) is similar. The key phrase is “assigned to the substance group”; however, there is no information or guidance in the IEC 62474 standard as to what is “ the substance group” for Lead sulfochromate yellow. You can’t necessarily jump to the conclusion that it is all declarable substance groups that have Lead sulfochromate yellow as a member.

Several possibilities for assigning the substance group arise; for example, the cation substance group could always be used (if applicable) or the anion substance group could be used. The substance group field in the declarable substance entry in the database could also be used to specify the substance group that should be used for the declarable substance; however, the substance group isn’t specified for most declarable substances in the DSL. Given that this situation was hypothetical at the time of writing the standard, there was reluctance to explicitly address this in the standard. The general intention, if this situation were to ever arise (which it has) was to let the responder (supplier filling out the material declaration) use their discretion to select the assignment of a declarable substance to a substance group.

So where’s the double reporting… the double reporting comes in because both declarable substance groups “lead/lead compounds” and “chromium (VI) compounds” must be declared. The Lead sulfochromate yellow substance declaration can only be assigned to one of these. If it’s assigned to lead/lead compounds, there is duplication in chromate mass because the current xml schema has no way to link the Lead sulfochromate yellow with the chromate substance group entry.

Interpretation of reporting threshold for declarable substances and declarable substance groups

For most of the declarable substance and declarable substance group entries in the IEC 62474 database, the reporting threshold is based on the mass percent of the product. This is represented by a reporting threshold that is listed as “0.1 mass%”. The reference to the mass of the product that is declared is implied in this threshold. However, there are other many declarable substances and declarable substance groups that have a reporting threshold that has a different calculation basis. The EU RoHS declarable substance groups are examples that use the mass of the homogeneous material as the basis for calculation.

How to interpret conditional fields in the IEC 62474 XML file

The IEC 62474 developer’s table includes a column (Obligation column) that indicates whether a specific data field (element or attribute) is mandatory or optional. Some data fields are listed as conditional. These fields are mandatory under certain material declaration conditions and optional under other conditions.

For example, Mass, MassPercent, and MatMassPercent are all listed as conditional. At least one of these data fields must be provided in a valid material declaration. The obligation column for Mass and MassPercent states: “Conditional (Either Mass or MassPercent is mandatory unless otherwise specified in IEC 62474 database)”. Basically, the data field is mandatory unless the information has been provided in one of the other mass related data fields. For most substance declarations, the supplier that is filling out the material declaration can decide whether they would like to provide the mass of the substance or the mass percent (weight/weight) of the substance.

The obligation description indicates that information provided in the IEC 62474 database may specify exactly which of these data fields needs to be provided. The most common situation for this is the EU RoHS substance groups which must be reported as a mass percent of the homogeneous material. In this case, the MatMassPercent element must be used to capture the mass information.

For substances that may be reported as a mass or mass percent, the standard technically allows the supplier to provide both data fields, but this is generally not recommended.  Experience with material declarations has shown that it’s easy to introduce errors (including rounding errors) when providing both numbers. This leaves the recipient of the material declaration uncertain as to which data field is actually correct.

June 30, 2014 update:  To prevent inconsistency between mass and mass percent information, the interpretation of allowing both mass and mass percent to be declared is being changed for the upcoming X5.00 version of the schema/developer’s table. The update will allow only mass or mass percent to be provided. X5.00 is forecast to be published in the fall of 2014 — an additional blog post will be provided when the new data exchange format is published on the IEC 62474 database.