The hazard classification of mixtures is often made by calculation based on component data rather than testing.
Method; The classification and concentration of each component is based on determining the class of the mixture using relevant concentration limits and additive rules. Bridging rules can also be applied for health and environmental hazards.
Correct calculation is the basis of correct label and SDS. ONAY Mühendislik performs mixture classification in accordance with the legislation.
How to determine classification in mixture
The hazard of the mixture is calculated based on the classification and concentrations of the components. There are defined concentration limits for each hazard class; If the component is above this limit, the mixture falls into that class. The calculation is made on a class basis, not on a component basis.
Bridging policies
If test data is available for a similar mixture, bridging principles may be applied in cases such as dilution or batch difference. This method does not require new testing, but the justification must be written in the file; What is asked in the audit is not the result, but how the result was reached.
Document the account
Keep the classification calculation with the ingredient list, proportions and limit values used. Recalculating by updating the same table when the formulation changes is much faster than starting from scratch.
If component data is missing
If the classification of the component is unknown, the mixture classification cannot be made. In this case, an updated safety data sheet and classification information is requested from the supplier. Predictive classification with incomplete data is one of the most difficult to defend situations in auditing.
Recalculate when formulation changes
Even small ratio changes can lead to exceeding or falling below the limit values. Repeating the classification calculation with each formulation revision also ensures that the label and UFI code remain current.
Common Mistakes in the Calculation Method
The most common mistake we encounter in mixture classification is that component concentrations are taken based on the percentage of commercial product instead of the percentage of pure substance. The second common mistake is not evaluating the additive components in total on the grounds that they are individually below the threshold. Thirdly, it is overlooked that the special concentration limits in the annex of the CLP Regulation replace the general limit values.
When is Test Data Required
The calculation method is not valid for every hazard class. In the case of mixtures with foaming agents, surfactants or pH extremes in classes such as skin corrosion, serious eye damage and respiratory sensitization, the calculation may underestimate the true effect. In these cases, test data on the mixture itself or bridging principles come into play; Which route was chosen should be stated with justification in section 16 of the safety data sheet.
Related pages
Contact ONAY Mühendislik for your process.
Official full text of the regulation: KKDIK Regulation - Official Gazette.
The calculated classification result is directly processed into parts 2 and 3 of the MSDS document; If the mixture classification changes, the form is also renewed.