Which compliance documents a heat sink needs: RoHS 3, REACH SVHC, UL material recognition and conflict minerals, and what a supplier can self-declare.
Heat Sink RoHS, REACH and UL Compliance Explained
Direct answer: An aluminium heat sink normally needs three compliance documents: a RoHS 3 (EU 2015/863) declaration, a REACH SVHC declaration against the current candidate list, and material or test reports if the buyer requests them. UL recognition is only relevant if the heat sink is part of a UL-listed assembly, and it applies to the material or component, not to the finished heat sink as a standalone product. Conflict minerals declarations are commonly requested for anything shipping into US supply chains.
Which documents apply to a heat sink
| Requirement | Applies? | What it covers | Who issues it |
|---|---|---|---|
| RoHS 3 (EU 2015/863) | Yes, if selling into the EU | Ten restricted substances including the four phthalates added in 2015 | Supplier declaration plus material certificates; third-party test if requested |
| REACH SVHC | Yes, if selling into the EU | Substances on the ECHA candidate list above 0.1% by weight per article | Supplier declaration against the current list version |
| Conflict minerals (3TG) and cobalt | Commonly requested for US supply chains | Tantalum, tin, tungsten, gold, and increasingly cobalt | Supplier CMRT declaration plus smelter information |
| UL 746 recognition | Only within a UL-listed assembly | The polymeric material used, e.g. a gap pad or adhesive | UL yellow card held by the material maker, not the heat sink factory |
| UL 796 / UL 94 for laminates and plastics | Only for non-metal components | Flammability of insulating parts | Material maker |
| California Prop 65 | Yes, if selling into California | Listed chemicals; aluminium itself is not the issue, coatings and adhesives can be | Supplier declaration |
| ISO 9001 / IATF 16949 | Buyer-dependent | Quality management system, not product compliance | Certification body |
What a compliance declaration actually means
A supplier declaration is a statement by the manufacturer that the product meets a specified requirement, based on their knowledge of the materials they buy and the processes they run. It is not a test result. The distinction matters when something goes wrong: a declaration shifts responsibility back to the declarer, a test report only covers the sample that was tested.
For an aluminium heat sink, the realistic compliance argument runs through the material and process chain:
- Alloy composition. 6063 and 6061 are aluminium-magnesium-silicon alloys. The RoHS restricted substances are not intentionally present, but recycled billet can carry trace contamination, which is why serious factories buy billet with a mill certificate.
- Anodising chemistry. Traditional hard anodising used hexavalent chromium in some sealing processes and chromate conversion coatings historically did too. Trivalent chromium processes are the current standard for RoHS compliance. Ask which process is used, not just whether the part is "RoHS compliant".
- Adhesives and gap pads. These are the highest-risk items on a heat sink assembly, not the metal. Thermal tape, structural adhesive and gap filler all contain organic chemistry that can carry SVHC or phthalates. If the heat sink is supplied with tape applied, the tape needs its own declaration.
- Packaging. EU packaging directive and, for some buyers, PFAS restrictions now extend to bags, labels and protective film.
The three questions that separate a real declaration from a PDF
- "Which revision of the REACH candidate list did you assess against?" The list is updated twice a year. A declaration against a three-year-old list is not a declaration. A competent supplier states the list date.
- "Do you have mill certificates for the billet in this batch?" This is where the alloy claim becomes traceable. If the answer is no, the RoHS claim rests on assumption.
- "Which anodising process do you use, and can you confirm trivalent chromium?" This is the most specific and most often failed question in aluminium heat sink compliance.
UL: where buyers usually get confused
There is no such thing as a "UL certified heat sink" in the way there is a UL listed power supply. What exists is:
- UL recognition of a material. A gap pad or adhesive may hold a UL 746 yellow card. That belongs to the material manufacturer.
- UL listing of an end product. The assembly, for instance a power supply or a luminaire, is listed. The heat sink is a component inside it and is evaluated as part of that listing.
- UL 94 flammability rating. Applies to plastics, not to an aluminium extrusion.
If a customer asks for UL on a bare aluminium heat sink, the correct response is to clarify what they actually need. Often it is a material yellow card for the thermal interface, or a UL 746C evaluation of the assembly, and neither is issued by the heat sink factory.
Building a compliance file that survives an audit
Assemble one folder per part number and keep it current. A workable structure:
| Document | Refresh trigger |
|---|---|
| RoHS 3 declaration, signed and dated | On any process or material change; otherwise annual reconfirmation |
| REACH SVHC declaration with candidate list date | Every candidate list update, twice a year |
| Material certificates for billet and coatings | Per batch, retained for the period your customer requires |
| CMRT conflict minerals declaration | Annually, or on supplier change |
| Process list including anodising chemistry | On process change |
| Third-party test reports, if requested | Typically every 1-2 years if the customer requires ongoing testing |
Frequently asked questions
Is an aluminium heat sink automatically RoHS compliant?
Not automatically. The bare alloy usually is, but the finish, the adhesive tape, the gap pad and the packaging all fall inside scope. A declaration should cover the delivered assembly, not just the metal.
Do I need a third-party lab test?
Usually not for a first order, and most buyers accept a supplier declaration supported by material certificates. If your customer's compliance team requires testing, budget for it explicitly and agree who pays.
What is the difference between RoHS 2 and RoHS 3?
RoHS 3, formally the 2015 amendment, added four phthalates (DEHP, BBP, DBP, DIBP) to the original six substances. A declaration that only lists six substances is out of date.
Can a Chinese heat sink factory issue a REACH declaration?
Yes. It is a declaration based on material knowledge, and it is normal practice. What you should check is whether it names the candidate list revision and whether it covers coatings and adhesives, not only the aluminium.
Ask us for the compliance pack for any part number and you will get the declarations with dates and the process list, not a generic PDF.
Heat sink sourcing guides
- Aluminum Heat Sink Price per kg: 2026 Cost Breakdown
- Custom Heat Sink MOQ and Lead Time by Process
- Heat Sink Extrusion Die Cost and Tooling Amortisation
- Heat Sink RFQ: What to Send for an Accurate Quote
- Heat Sink Tolerance and Flatness: What to Specify
- Heat Sink Surface Finish Options and Cost Impact
- Heat Sink Volume Pricing: How Breakpoints Really Work
- Heat Sink Prototype and Sample Service: What to Expect
- Heat Sink Packaging, Shipping and DDP Terms
- Heat Sink Supplier Audit and Second Sourcing
- Heat Sink Thermal Test Report: What the Data Package Contains
