What Entry 50 actually restricts
The extender-oil provision in REACH Annex XVII entry 50 sets direct concentration limits for named polycyclic aromatic hydrocarbons in oils used in tyre and tyre-part manufacture. The key thresholds are 1 mg/kg for benzo(a)pyrene and 10 mg/kg for the sum of eight specified PAHs.
If either threshold is exceeded, the extender oil may not be placed on the market or used for that tyre-manufacturing purpose within the scope of the regulation.
The method the regulation actually specifies
The method identified for demonstrating conformity is EN 16143:2013, a GC/MS-based procedure that measures benzo(a)pyrene and selected PAHs directly in extender oils.
That matters because the regulatory limit is expressed in mg/kg for specific compounds. The test report should therefore show the individual compounds and the summed result against the legal thresholds.
Where IP 346 fits — and where it does not
IP 346 is a legitimate petroleum test method, but it answers a different question. It measures DMSO extract content as a percentage and has historically been used as a screening proxy in base-oil carcinogenicity classification contexts.
- Different measurand: IP 346 reports a DMSO extract percentage; EN 16143 reports specific PAHs in mg/kg.
- Different regulatory role: Entry 50 names EN 16143:2013 for extender-oil conformity.
- No clean conversion: an IP 346 percentage is not simply the same PAH result in another unit.
| Aspect | IP 346 | EN 16143:2013 |
|---|---|---|
| Measures | DMSO extract content | Eight selected PAH compounds by chromatographic / MS analysis |
| Reported as | Percentage extract | mg/kg per compound and sum |
| Historical use | Base-oil screening / classification discussions | Direct PAH determination in extender oils |
| Named by Entry 50 for extender-oil conformity | No | Yes |
What buyers and suppliers should do
If a TDAE, RPO or other extender oil is being represented as suitable for tyre manufacture under REACH Entry 50, request the EN 16143:2013 test report showing the relevant PAH results. A generic “low PAH” statement or IP 346 result alone does not demonstrate the specific Entry 50 limits.
If documentation only cites IP 346, treat that as a documentation gap to resolve. It does not automatically mean the oil fails; it means the evidence provided is not the evidence the Entry 50 provision names.
Practical procurement checklist
- Confirm the end use is tyre or tyre-part manufacture where Entry 50 applies.
- Request EN 16143:2013 data.
- Verify benzo(a)pyrene is within 1 mg/kg.
- Verify the sum of the eight listed PAHs is within 10 mg/kg.
- Keep the supplier statement, test report and batch traceability linked to the shipment.
FAQ
Is IP 346 a bad test? No. It is a valid method with other industry uses. It is simply not the method Entry 50 specifies for this extender-oil PAH conformity question.
Does this affect TDAE and RPO? It affects extender oils supplied for tyre or tyre-part manufacture within the scope of the regulation. If conformity is claimed, the documentation should support it with the correct method.
Qualifying an extender oil for regulated tyre use?
Send the grade, intended application, destination and available PAH documentation. We can qualify the procurement requirement before quotation.
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