What counts as clean rubber granules?
For physical contamination, replace 'clean granules' with separate checks for steel, textile and other unwanted material. Define what each check measures, how the result is reported and what happens near the limit. A photograph or an undefined 'steel-free' label is not enough to accept material for your production process.
Explore the questionsThree checks, not one purity number
- Steel
Which metal fraction does the method measure, and which does it leave outside its scope?
- Textile
Name the fibre fraction being measured and the agreed reporting unit.
- Other material
List the foreign material your process cannot accept, with a check for each relevant category.
Name the fraction
Free steel, textile and other impurities need clear definitions. Do not treat them as interchangeable results.
Pair limit with method
A maximum value needs a test method, reporting basis and sample identity beside it.
Decide before delivery
Agree how borderline results and visible foreign material will be reviewed before material is released for use.
Buying and Importing
Choose the question you want to explore.
What belongs in a physical-contamination requirement?
Use separate lines for the things you need to control, rather than a single cleanliness claim.
The public scope of EN 14243-2 includes impurity measurements for tyre-derived granulates and powders, including free steel and free textile. That is a useful starting point for naming the checks, not evidence that a particular shipment has passed them.
- Steel: ask exactly which fraction the reported result covers. Do not assume a free-steel result answers every question about metal.
- Textile: identify the fraction and method rather than accepting an undefined ‘fibre-free’ description.
- Other unwanted material: tell the supplier what your process must exclude and ask how it can be assessed.
These are physical-material checks. They do not establish chemical compliance or finished-product safety.
Which details make a result comparable?
Keep the property, method, unit and sample identity together.
Use this short specification line for each property:
- Property: the defined fraction being measured.
- Method: the named procedure and version, including any agreed deviation.
- Result: the value, unit, reporting basis and any qualifier such as ‘less than’.
- Identity: the sample and material lot to which the result applies.
NEN’s scope for EN 14243-2 also includes collecting and preparing a representative sample under a sampling plan. A close-up photograph cannot replace that measurement chain. Use the sample-to-container checklist to connect the evaluated sample with the proposed supply. Ask the laboratory or responsible technical team to select the appropriate procedure; this guide does not reproduce the standard.
How will you handle a result near the limit?
Set the acceptance rule before testing, not after an inconvenient result arrives.
A measured value and an acceptance decision are related, but they are not the same thing. Eurachem’s compliance-assessment guide explains how measurement uncertainty and a decision rule affect judging a result against a limit.
Ask your laboratory and supplier to agree how this applies to the chosen check. The practical questions are: what counts as a pass, what requires clarification, and when is a repeat or additional test appropriate? Follow any applicable prescribed rule. Do not choose a new rule after seeing the result, or read ‘below the reporting limit’ as proof of absolute zero.
Keep a separate route for a visible foreign object or damaged package that the numerical report does not address: record it, identify the affected material and seek review before release into production.
What should go into the granule enquiry?
Send the acceptance requirement with the application, not just a request for the cleanest grade.
For a rubber granule enquiry, send the product you make, required grade, quantity and destination, together with your physical-contamination limits and methods. If you do not yet have limits, say which part of your process needs protecting and ask your technical team to define suitable checks.
Keep this request specific: ‘Please confirm which steel, textile and other-impurity results are available for the proposed material, and identify any checks that would need to be arranged.’ Bedrock must confirm the available evidence and achievable specification for the proposed order. This article is not a zero-contamination guarantee or a commitment to provide an unconfirmed test.
Have a contamination specification?
Send your grade, application and acceptance limits, with the methods your team uses. We can discuss the proposed material and confirm which supporting information is available.
Discuss granule requirementsCommon questions
Does 'steel-free' mean exactly zero steel?
Not without a defined meaning and supporting evidence. Ask which fraction was checked, by what method, and how results below the reporting limit are expressed.
Can I combine steel and textile into one limit?
Keep the individual requirements visible if each matters to your process. A combined total can hide which material is present and does not replace the individual checks you agreed.
Does passing these checks approve the finished product?
No. Physical-contamination acceptance is one part of material selection. The manufacturer or project team still needs the other chemical, process and finished-system evidence relevant to the intended use.