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OECD Guidance for Characterising Hydrocarbon Solvents for Assessment Purposes

March 25th, 2016

The Organisation for Economic Co-operation and Development (OECD) has issued guidance on characterisation of UVCB hydrocarbon (HC) solvents.

These substances range from 5-20 carbons, comprising the hydrocarbon classes of paraffins, isoalkanes (branched alkanes), naphthenes, aromatics, n-alkanes (or n-paraffins/saturated linear alkanes), branched alkanes (isoparaffins) and cycloalkanes.

The OECD guidance stipulates that:

  • All carbon numbers and HC classes with a concentration of ≥10% should be characterised as UCVB HC. The sum of the maximum concentration values for each carbon number mentioned in the name should be at least 80% (w/w).
  • When a group of constituents has the same carbon number, each present at ≥10% that in total do not compose ≥80% (w/w) of the substance, all carbon numbers (whatever the concentration) should be considered for the characterisation.
  • Typically five different batches over a given period should be analysed to obtain a typical concentration.

The following should be specified in the name

  • When aromatic concentration is < 2%
  • 2-35% aromatics lower boiling HC solvents
  • 2-30% in higher boiling HC solvent
  • If the maximum concentration value of a toxic constituent above a classification cut-off must be specified (i.e. toxic substance > cut-off x%)

Often it is challenging to determine analytically the quantitative criteria or cut-off values for carbon numbers, due to the carbon number distribution or combination hydrocarbon classes.

The guidance can be found here.

OECD (8 Jan 2016) OECD Guidance for Characterising Hydrocarbon Solvents for Assessment Purposes, Series on Testing and Assessment No. 230, OECD