Skip to main content

Table 4 Summary of studies generating and analysing isocyanates in fire effluents. Summary of the large-scale fire test and bench-scale methods for generating isocyanates and the materials used, as well as sampling methods, temperature, the isocyanates detected and concentration

From: The role of isocyanates in fire toxicity

Study Test method and materials Sampling method Temperature (°C) Isocyanates detected Isocyanate concentration Comments
Boutin et al (2004) DIN 53436 furnace
Car paint
Sample temperature:473
Oven temperature: 600
ICA, HDI, all linear isocyanates ranging from MIC to n-hexyl isocyanate, alkenyl isocyanates ranging from propylene to octylene isocyanate and structural isomers of these isocyanates N/A The most abundant isocyanates detected were MDI, HDI, TDI and IPDI.
Hertzberg et al (2003) Room test (ISO19705)
Sofa (containing PUR)
N/A ICA, PHI, MDI, 2,4-TDI and 2,6-TDI The average isocyanate concentration measured was approximately 0.5 ppm The highest concentrations were found in the rigid foams, with PIR, an improved form of PUR, giving the highest yield.
In all foams ICA was the main product and was considered the final breakdown product.
The ratio of ICA to TDI was much higher in full- scale experiments in comparison to the combustion of flexible PUR in the cone calorimeter
Cone calorimeter (ISO5660)
Insulation materials
N/A ICA, MIC ~800-1000 μg m-3 Glass fibre insulation gave the highest isocyanate concentration of all materials tested.
ICA and MIC were the most abundant isocyanates.
Karlsson (2001) Urea-based resins and PUR coated sheets Impinger-filter
N/A ICA, MIC In Bakelite up to 14 % of its weight was emitted as ICA and 0.1 % as MIC These amounts dependant on temperature and the duration of the heating.
The composition of the released isocyanates differs between coatings.
Blomqvist et al (2003) PUR mattresses were used a fire source to trigger a sprinkler system, according to IMO resolution A.800 Impinger-filter
N/A ICA and smaller amounts of 2,4-TDI and 2,6-TDI First test: close to 10 ppb. Second test; 50 ppb. Comparing the potential health hazard between isocyanates and other major fire gases revealed isocyanates as the greatest hazard.
Lönnermark and Blomqvist (2006) ISO 5659, large-scale
car fires
N/A ICA, EIC, MIC, PHI, 2,4-TDI, 2,6-TDI, HDI Total yield of airborne isocyanates: 240 g/kg Significant amounts of isocyanates were found in the smoke from the vehicle fires
Blomqvist et al. (2007) Identical setup to BS 7990:2003
PUR mattresses and insulation material, wood
650 °C and 825 °C ICA, TDI, EIC PUR mattress:~ 2 mg/g
PUR insulation: :~ 2.5 mg/g
Wood: 0.0035 mg/g
Two different fire scenarios were investigated; well-ventilated and under-ventilated
No significant differences in isocyanate generation were detected for the two fire scenarios
Blomqvist et al. (2014) ISO/TS 19700
PVC carpet, wood board
350 °C, 650 °C and 825 °C ICA, MIC, EIC, PHI, MDI   Distribution of isocyanates in gas phase and particle phase were investigated
Mono-isocyanates were found almost exclusively in the gas phase
Only small amounts of di-isocyanates were found
(Fent and Evans (2011)) Vehicle fire Denuder
DBA impregnated filter
N/A TDI, MDI, HDI, PHI, MIC, EIC, PIC, IPDI, ICA 5.9-66.8 μg m-3 TRIG (total reactive isocyanate groups) Isocyanates were only found in passenger compartment fires and not in engine fires. Isocyanates are present in foam in the passenger compartment and not used in engines.
HSL 2007 Simulated workplace samples (welding of PU painted car parts) MP impregnated filter 200 °C TDI, MDI, HDI, PHI, MIC, EIC, PIC, IPDI, ICA, butyl isocyanate, diisopropylphenyl isocyanate, hydrogenated MDI High levels of ICA (167 mg NCO/m3)) and traces of other isocyanates  
MP impregnated filter 400 °C TDI, MDI, HDI, PHI, MIC, EIC, PIC, IPDI, ICA, butyl isocyanate, diisopropylphenyl isocyanate, hydrogenated MDI High levels of ICA (167 mg NCO/m3)) and traces of other isocyanates
  1. N/A indicates level not available/not applicable