By Mike Kirschner, Design Chain Associates
Certain product categories, primarily consumer electronics like laptops and cell phones, are under pressure to comply with “low halogen” requirements. These requirements are generally not regulatory right now – rather, they are “market requirements”. The initial rationale for these standards was driven primarily by concerns about the production and ingestion of highly toxic compounds during low-temperature combustion in non-professional recycling situations. For example, in Asia and Africa cables/boards/etc. were/are burned in open fires to enable easier access to the more valuable metals like copper. Today we can include increasing concern about the seemingly never-ending stream of evidence of environmental and human health safety issues surrounding halogenated compounds that are used in electronics. These include:
- Chlorinated and brominated flame retardants are, as classes, toxic enough and product users can be sufficiently exposed to warrant an upcoming restriction per the US Consumer Product Safety Commission (see my entry on this in the October 2017 column; the National Academies is now “forming a committee that will develop a scientifically based scoping plan to assess additive, nonpolymeric organohalogen flame retardants (OFRs) as a class for potential chronic health hazards under the Federal Hazardous Substances Act (FHSA)”)
- All of the “Persistent Organic Pollutants” banned under Annex A of the Stockholm Convention are organohalogens; many are flame retardants
- When combusted at low temperatures, as is often the case in order to access more valuable metals in insulated wiring and cables for illegal recycling, halogenated polymers produce more toxic byproducts than non-halogenated polymers
Two standards are commonly cited when products must comply with “low halogen” requirements:
- IEC 61249-2-21:2003 – Materials for printed boards and other interconnecting structures – Part 2-21: Reinforced base materials, clad and unclad – Non-halogenated epoxide woven E-glass reinforced laminated sheets of defined flammability (vertical burning test), copper-clad
- JS709C – JOINT JEDEC/ECA STANDARD, DEFINITION OF “LOW-HALOGEN” FOR ELECTRONIC PRODUCTS
I occasionally see a third cited:
- IPC/JEDEC J-STD-609B – JOINT INDUSTRY STANDARD – Marking, Symbols, and Labels of Leaded and Lead-Free Terminal Finished Materials Used in Electronic Assembly
IEC 61249-2-21 covers only printed circuit boards, while JS709C covers everything else used in “electronic products”. J-STD-609B is a marking standard only but is sometimes cited. Here are the definitions in these standards:
- IEC 61249-2-21 (and IPC/JEDEC J-STD-609B):
- “Halogen-free board”: Printed board resins plus reinforcement matrix that contain maximum total halogens of 1500 ppm with less than 900 ppm bromine and less than 900 ppm chlorine.
- JS709C definition of “Low-Halogen”:
- Each material within an electronic product, (excluding printed board laminates) shall contain <1000 ppm (0.1%) by weight of bromine if the bromine source is from BFRs and <1000 ppm (0.1%) by weight of chlorine if the chlorine source is from CFRs, PVC, PVC congeners, PVC block polymers, PVC copolymers, or polymer alloys containing PVC. Higher concentrations of bromine and chlorine are allowed in plastics contained within electronic products (other than printed board laminates contained within those devices) as long as their sources are not flame retardants, PVC, PVC congeners, PVC block polymers, PVC copolymers, or polymer alloys containing PVC.
- All printed board laminates contained within electronic and electrical products, including those within a passive or solid-state device shall meet the “halogen-free” requirements for Br and Cl as defined in the most current version of one of the following specifications: IEC 61249-2, IPC-4101, JPCA-ES-01.
Several issues complicate the situation:
- The family of halogens also includes fluorine, iodine and astatine. These are not included in either standard’s definitions. Fluorine-based substances, while far less common than Br and Cl, are increasingly used in electronic components and materials, including in flame retardants for polycarbonates. Iodine has very limited uses and astatine is not used, as it is radioactive and “much less than one gram is present at any given time in the Earth’s crust.”
- The scopes of these standards differ. JS709 targets a finished good scope, incorporating IEC 61249-2-21 as the standard for bare printed circuit boards.
- The concentration limits are different. Close, but different.
- They use different terminology: IEC 61249-2-21 defines “halogen-free” while JS709 defines “low-halogen”.
- Both are, explicitly or implicitly, targeting flame retardants (FRs). JS709 also targets PVC, which has a level of flame retardance due to the presence of chlorine but often requires a synergist like antimony trioxide or other additives to meet flammability standards. JS709 allows non-FR and non-PVC applications of bromine and chlorine.
- Because of #1 above as well as the scope limitations in the definitions, neither guarantees that a product is truly “halogen-free” or “low halogen”, as the general public would interpret it.
- JS709 was issued by JEDEC and ECA, component-focused industry standards bodies. IPC, which is somewhat broader in its scope, pulled out of the development of this standard before the first version was issued. JEDEC and ECA kept the scope of the standard broad, despite their lack of coverage broader than components. Some system/finished-goods-level organizations have concerns about the standard’s validity because of this lack of representation within the developing organizations.
- Many in the electronics industry are cynical about the need for these requirements; they see it as market-driven rather than science-driven. The science has not been well explained and has been seriously discounted by the chemical industry.
Manufacturers across the supply chain, from OEMs to component and material manufacturers, often fail to apply the correct specification; I have seen the IEC standard specified when covering everything in a finished good and suppliers refer to it for non-PCB components and materials. In fact, the JS709C standard is, in theory, the proper standard to use at the product or system level, and for all non-PCB components and materials.
The IEC did issue IEC/PAS 63015:2016, which is simply JS709B (a previous version) with an IEC boilerplate in front of it. This was probably an attempt to set a starting point for a “horizontal” international standard for “electrotechnical” products and to indicate that it considers the standard adequate, for now, for system/finished-goods level manufacturers. This may be renewed for 3 years in 2019.
IEC then attempted to create a new standard covering the low-halogen/no-halogen/halogen-free requirement in what would have been called IEC 63031. But after two attempts failed the project has now been cancelled.
In order to create a valid, meaningful and broadly applicable low halogen standard at the IEC “electrotechnical” level (which is where such a standard belongs, in my humble opinion), several areas must be researched, understood and agreed upon. These include:
- Common understanding of the toxicity and exposure risk of halogens across the product lifecycle, including citations of credible and relevant studies and research
- Ensuring the awareness of substance, material and design alternatives that enable products to continue to meet safety and functional requirements and goals
- Agreement on both halogen and product scopes based on substances used in the defined product scopes
- This requires identifying applications of halogenated substances (Br, Cl, F, maybe I) beyond flame retardants and PVC in order to define the scopes of elements and products. F-based substances have an increasingly broad spectrum of applications in interesting places, like MEMS devices as well as improving polycarbonate flammability performance.
- Potentially, the identification and/or development of supporting test procedures.
With halogen-based flame retardants in the continuing crosshairs of regulatory agencies, the industry will either step up and define a path forward, or once again allow governments – and Environmental NGOs – to define environmental and human health safety requirements for its products.