Table 1.
Geometric mean diameter of beryllium powders and process-sampled particles
| Cyclone | Geometric mean, μm (GSD)A | ||||
| Material | Stage | D50 (μm) | PCM | CCSEM | LPC |
| Be metal powder | 2 | 2.5 | 3.0 (1.8) | NPB | 1.5 (1.8) |
| 3 | 1.7 | 2.7 (1.7) | NP | 1.3 (1.5) | |
| 4 | 0.9 | 2.0 (1.5) | 1.1 (1.9) | 1.1 (1.6) | |
| BeO powder | 2 | 2.5 | 1.0 (1.3) | NP | 1.1 (1.3) |
| 3 | 1.7 | 1.2 (1.5) | NP | 1.0 (1.3) | |
| 4 | 0.9 | 1.0 (1.4) | 0.9 (1.5) | 1.0 (1.3) | |
| Process BeO | 2 | 2.3 | 1.2 (1.6) | NP | --C |
| 3 | 1.5 | 1.1 (1.6) | NP | -- | |
| 4 | 0.7 | 1.2 (1.6) | 1.0 (1.9) | -- | |
| Process alloy | 2 | 2.3 | 2.1 (1.9) | NP | 1.1 (1.3) |
| 3 | 1.5 | 1.9 (1.7) | NP | 1.0 (1.3) | |
| 4 | 0.7 | 1.6 (1.7) | --D | 0.9 (1.3) | |
A GSD = geometric standard deviation
B NP = analysis not performed for this size-fraction
C For the sake of efficiency in experimental design, separate LPC analyses were not performed for the process BeO material because the BeO powder material was considered representative of the process BeO material.
D Greater than 60% of these particles were 0.4–0.7 μm precluding graphical determination of the GM