Workplace exposure - Measurement of dustiness of bulk materials that contain or release respirable NOAA or other respirable particles - Part 5: Vortex shaker method
This document describes the methodology for measuring and characterizing the dustiness of bulk materials that contain or release respirable NOAA or other respirable particles, under standard and reproducible conditions and specifies for that purpose the vortex shaker method.
This document specifies the selection of instruments and devices and the procedures for calculating and presenting the results. It also gives guidelines on the evaluation and reporting of the data.
The methodology described in this document enables
a) the measurement of the respirable dustiness mass fraction,
b) the measurement of the number-based dustiness index of respirable particles in the particle size range from about 10 nm to about 1 µm,
c) the measurement of the number-based emission rate of respirable particles in the particle size range from about 10 nm to about 1 µm,
d) the measurement of the number-based particle size distribution of the released respirable aerosol in the particle size range from about 10 nm to 10 µm,
e) the collection of released airborne particles in the respirable fraction for subsequent observations and analysis by electron microscopy.
This document is applicable to the testing of a wide range of bulk materials including nanomaterials in powder form.
NOTE 1 With slightly different configurations of the method specified in this document, dustiness of a series of carbon nanotubes has been investigated ( to ). On the basis of this published work, it can be assumed that the vortex shaker method is also applicable to nanofibres and nanoplates.
This document is not applicable to millimetre-sized granules or pellets containing nano-objects in either unbound, bound uncoated and coated forms.
NOTE 2 The restrictions with regard to the application of the vortex shaker method on different kinds of nanomaterials result from the configuration of the vortex shaker apparatus as well as from the small size of the test sample required. Eventually, if future work ...