Overview
ISO/TR 17737:2012 - Workplace atmospheres: Guidelines for selecting analytical methods for sampling and analysing isocyanates in air - is an informative Technical Report from ISO/TC 146 that helps industrial hygienists, employers and workers understand isocyanates, their industrial uses, health risks and practical approaches to air monitoring. The report explains that isocyanates (compounds with −N=C=O groups, e.g. MDI, TDI, HDI, IPDI) can occur as gas- and particle-phase species and are a leading cause of occupational asthma, often having very low occupational exposure limits (OELs). ISO/TR 17737:2012 focuses on choosing appropriate sampling and analytical methods to obtain representative workplace-air measurements.
Key Topics
- Nature and sources of isocyanates: monomers, polyisocyanates, prepolymers and thermal decomposition products; common industrial uses (polyurethane production, coatings, spray painting, insulation, adhesives).
- Airborne behaviour: gas vs aerosol distribution, reacting aerosols, and release during thermal degradation (noted onset above ~150–200 °C).
- Sampling alternatives:
- Impregnated filters (derivatizing reagent coated) for gas and many particle forms.
- Impinger (and filter) combinations for both phases, recommended when atmosphere composition is uncertain or for reacting aerosols.
- Sorbent tubes (impregnated) mainly for vapour-phase isocyanates, with filter backup for particles.
- Denuder + filter systems to separate gas and particulate fractions.
- Diffusive samplers and direct-reading instruments (overview only).
- Specific proposed/adopted methods: listed approaches such as DBA, double-filter, MAP, MP and PP methods (summarized in the report).
- Analysis, interferences and practical considerations: importance of immediate extraction/derivatization, potential interfering reactive species, sampler fragility, solvent vapour issues and representativeness.
Applications
- Industrial hygiene programs: select appropriate air-monitoring strategies in manufacturing, painting, insulation, automotive repair, foundries and other activities where isocyanates are used or formed.
- Exposure assessment and compliance: support measurement campaigns to compare exposures to relevant OELs and identify control needs.
- Process safety and product evaluation: assess thermal decomposition risks during hot processes (welding, melting, hot-box casting) and evaluate prepolymers vs monomers.
- Who uses it: industrial hygienists, safety professionals, laboratory analysts, employers, regulators and occupational health practitioners.
Related Standards (if applicable)
- Prepared by ISO/TC 146 (Air quality) - consult other ISO standards and guidance on workplace atmospheres, sampling protocols and laboratory analysis when implementing ISO/TR 17737:2012.