Standards Development

Scope

This part of ISO 17734 gives general guidance for the sampling and analysis of airborne isocyanates in workplace air. When amines and aminoisocyanates are suspected to be emitted (e.g. from thermal degradation of PUR), it is recommended that, in addition to isocyanates, the amines and aminoisocyanates in the air are determined, using DBA and ethyl chloroformate as reagents (see ISO 17734 2).

The method is suitable for the determination of a wide range of different isocyanates in both the gas and particle phases. Typical monofunctional isocyanates that can be determined are isocyanic acid (ICA), methyl isocyanate (MIC), ethyl isocyanate (EIC), propyl isocyanate (PIC), butyl isocyanate (BIC), and phenyl isocyanate (PhI). Typical monomeric diisocyanates include 1,6-hexamethylene diisocyanate (HDI), 2,4- and 2,6-toluene diisocyanate (TDI), 4,4’-methylenediphenyl diisocyanate (MDI), 1,5-naphthyl diisocyanate (NDI), isophorone diisocyanate (IPDI), and 4,4’-dicyclohexylmethane diisocyanate (HMDI). Multifunctional isocyanates that can be determined are typically oligomers in polymeric MDI, biuret-, isocyanurate-, and allophanate-adducts, and prepolymeric forms of isocyanates.

The useful range is approximately 2,5 ng to 500 ng of isocyanate per sample. For a 15 l air sample, this corresponds to 0,2 µg/m3 to 33 µg/m3. These values can slightly change according to the isocyanate analysed.