Más contenido relacionado Similar a Stefan Hahn - Validation of the Deterministic Indoor Air Model SprayExpo (7) Stefan Hahn - Validation of the Deterministic Indoor Air Model SprayExpo1. Validation of the deterministic
indoor air model SprayExpo
Stefan Hahn*, Annette Bitsch, Katrin Schröder, Edith Berger-Preiss, Heiko Kock,
Wolfgang Behnke, Wolfgang Koch
Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
* contact: stefan.hahn@item.fraunhofer.de
Abstract
Sensitivity analysis as well as comparison of modeled values with measured values
(Antifouling treatment and stored-product protection)
Most influencing parameters: substance release rate and the droplet spectrum of
the spraying device, size of room (room spraying)
Minor impact: size of room (for surface spraying), diffusion constant and the air
exchange rate
SprayExpo sufficiently appropriate (max factor 4-5)
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2. Measurements
The exposure concentrations of the active
substances used were determined by time-resolved
and particle size-segregated personal sampling
(Respicon) and subsequent chemical analysis.
Model description (www.tsi.com)
Model features
Deterministic droplet transport model
Turbulent mixing
Gravitational settling
Droplet evaporation
Required input
Spray path
Spray technology (droplet spectrum)
Release rate and time
Substance data
Room geometry and ventilation
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3. Sensitivity analysis (exemplarily VP)
V a p o r p re s s u re [h P a ]
Vapour pressure of solvent (usually higher than
10 Pa) has only minor impact on the exposure
concentration
With decrease of mean droplet diameter the
exposure concentration will increase
D 5 0 [µ m ]
Model room
For SprayExpo deviations are found only at low
concentrations below 0.5 mg/m3
Strong impact of the “room size” when dealing
with large particles
For small particles the differences between the
two models/tools are only small
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5. Conclusion
SprayExpo is sufficiently appropriate
to predict exposure values to
aerosols of non-evaporable
substances in indoor environments.
Validation of SprayExpo is of
relevance for regulatory acceptance
of this tool to assess the exposure to
hazardous substances during indoor
spray application.
Acknowledgement:
The results presented were part of a research project (F2137) on behalf of
the German Federal Institute for Occupational Safety and Health
(Bundesanstalt für Arbeitsschutz und Arbeitsmedizin).
The authors would like to thank Martin Tischer (presentation Thursday
9:30h, Session 11b) and Dagmar Holthenrich for general scientific support.
For more information on our work please visit
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www.item.fraunhofer.de