Method for evaluating dispersibility of powder and method for evaluating concentration of airborne powder, and method for designing containment facility using the same

1. A method for evaluating powder dispersibility comprising the steps of:

dispersing a powder allowed to stand inside a closed container by mechanical vibration applied quantitatively to the powder using a vibratory device;

drawing air inside the closed container that contains the dispersed powder into an apparatus,

collecting the dispersed powder on a quartz crystal element provided in the apparatus; and

measuring a mass of the collected powder using a quartz crystal microbalance and the volume of air drawn into the apparatus to thereby measure an airborne powder concentration in air inside the closed container based on the mass of the powder and the volume of air collected in the apparatus.

2. The method for evaluating powder dispersibility according to claim 1 , wherein the mass of the powder allowed to stand inside the closed container is within a range from 0.1 g to 5 g.

3. A method for evaluating airborne powder concentration comprising the steps of:

measuring an airborne powder concentration of a surrogate powder by the method of claim 1 or 2 for evaluating powder dispersibility;

calculating a logarithm of the airborne powder concentration (airborne index d);

measuring an airborne concentration C′ of the surrogate powder in a working environment;

producing a calibration curve F(d) from the airborne index d and the airborne concentration C′; and

predicting an airborne concentration C of an actual target powder in the working environment from the airborne index d of the actual target powder using the calibration curve F(d).

4. A method of designing a powder containment facility comprising the steps of:

predicting dispersibility of an actual target powder in an actual working environment by the method of claim 3 for evaluating airborne powder in concentration; and

designing a powder containment facility based on a predicted result.

5. The method for assessing powder dispersibility according to claim 1 , wherein the apparatus is a cascade impactor.

6. The method for assessing powder dispersibility according to claim 1 , wherein the volume of the closed container is within a range of 100 ml to 300 ml.

7. The method for assessing powder dispersibility according to claim 1 , wherein a period for applying mechanical vibration is within a range of 10 to 15 seconds.