Status:
completed 12/2007
Aims:
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detection and identification of polymeric isocyanates at workplaces
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validation of alternative analytical methods for isocyanates
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definition of safe PUR-workplaces
Activities/Methods:
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air sampling at workplaces
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air sampling at model workplaces
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HPLC-analysis
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HPLC-MS-analysis
Results:
Methodic studies of sampling and analytics:
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It could be shown that the air samples within the range of 1-3 l/min have been independent from the active volume flow rate
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The sampling time had a great impact on the results
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Quasi-continuous methods are improper for the evaluation of work places. For the detection of emission sources they could be used
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It is recommended to identify isocyanates with a material calibration
Evaluation of the work place situation:
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Slot jet application leads to lesser isocyanate exposition compared to barrel application
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Humidity in the range of 20-50% show no significant influence on air concentration of isocyanates
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In operational measurements monomer concentrations lower 0.1% lead to lower MDI air concentrations
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The ambient temperature has no effect on the air concentration in the temperature range of 15-25°C
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The processing temperature has a significant impact on the adhesive emissions
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The local exhaust ventilation or the housing of sources leads to significant reduced MDI air concentration
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With increasing distance to the emission source the isocyanats exposure decreases. While for single emission sources this effect is clearly observed, isocyanate emissions of multiple sources interfere.
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The definition of a secured work place by means of distance to the emission source is not complete without consideration of the facility geometry and the knowledge of air supply and ventilation capacity.
Last Update:
6 Oct 2009
