430
K. Vaupel et al.
Table 5 Prediction functions for single drop method under different environmental conditions [6]
Environmental conditions
Forecasting functions
20% relative humidity
E max = −14.32 + 30.98 log K SD
E 30 = −11.80 + 21.49 log K SD
50% relative humidity
E max = −19.19 + 29.14 log K SD
E 30 = −14.10 + 17.79 log K SD
80% relative humidity
E max = −20.00 + 29.30 log K SD
E 30 = −14.04 + 17.33 log K SD
Low vacuum
E max = −14.76 + 24.71 log K SD
E 30 = 8.88 + 14.91 log K SD
Table 6 Prediction functions for rotating method, X A = moisture content of material sample, X 0.9
= moisture content of a material at 90% relative humidity [6]
Dry bulk material
log S RD,dry = 3.11 – 0.67 K RD
Wet bulk material
log (S RD,wet /X 0.9 ) = 2.21 (X A K RD ) −0.14
In case of rotating drum method, the apparatus specific calculation factor K RD is
based on Eq. (6). Mean prediction functions for dry and wet bulk materials are given
in Table 6.
K RD =
d 32,GP / d 32
· (1/ε) · x 50,3 /
x 90,3 − x 10,3
(6)
ε is bulk porosity; d 32 is Sauter diameter; d 32,GP is Sauter diameter taking into account
all particles larger than 2.9 µm for dry bulk material and 3.9 µm for wet bulk material;
x i,3 is a percentile of the particle size distribution by mass.
In case of the UNC dustiness tester only the amount of total dust is predicted (see
Eq. (7) and Table 7).
K UNC = (3/2) · (μm/ d 32 ) · ((1 − ε)/ε) ·
d 32,GP / d 32
· x 50,3 /
x 90,3 − x 10,3
(7)
ε is bulk porosity; d 32 is Sauter diameter; d 32,GP is Sauter diameter taking into
account all particles larger than 8.8 µm (for dry bulk material); x i,3 is a percentile of
the particle size distribution by mass.
Table 7 Total dust prediction functions for UNC dustiness tester, X A = moisture content of material
sample, X 0.8 = moisture content of a material at 80% relative humidity [6]
Dry bulk material log S UNC,dry = 0.93 exp (−0.15 K UNC )
Wet bulk material log (S UNC,wet X A ) = 0.50 + 0.44 (ε X A X 0.8 (x 90,3 − x 10,3 )/(x 90,2 −
x 10,2 ))
K. Vaupel et al.
Table 5 Prediction functions for single drop method under different environmental conditions [6]
Environmental conditions
Forecasting functions
20% relative humidity
E max = −14.32 + 30.98 log K SD
E 30 = −11.80 + 21.49 log K SD
50% relative humidity
E max = −19.19 + 29.14 log K SD
E 30 = −14.10 + 17.79 log K SD
80% relative humidity
E max = −20.00 + 29.30 log K SD
E 30 = −14.04 + 17.33 log K SD
Low vacuum
E max = −14.76 + 24.71 log K SD
E 30 = 8.88 + 14.91 log K SD
Table 6 Prediction functions for rotating method, X A = moisture content of material sample, X 0.9
= moisture content of a material at 90% relative humidity [6]
Dry bulk material
log S RD,dry = 3.11 – 0.67 K RD
Wet bulk material
log (S RD,wet /X 0.9 ) = 2.21 (X A K RD ) −0.14
In case of rotating drum method, the apparatus specific calculation factor K RD is
based on Eq. (6). Mean prediction functions for dry and wet bulk materials are given
in Table 6.
K RD =
d 32,GP / d 32
· (1/ε) · x 50,3 /
x 90,3 − x 10,3
(6)
ε is bulk porosity; d 32 is Sauter diameter; d 32,GP is Sauter diameter taking into account
all particles larger than 2.9 µm for dry bulk material and 3.9 µm for wet bulk material;
x i,3 is a percentile of the particle size distribution by mass.
In case of the UNC dustiness tester only the amount of total dust is predicted (see
Eq. (7) and Table 7).
K UNC = (3/2) · (μm/ d 32 ) · ((1 − ε)/ε) ·
d 32,GP / d 32
· x 50,3 /
x 90,3 − x 10,3
(7)
ε is bulk porosity; d 32 is Sauter diameter; d 32,GP is Sauter diameter taking into
account all particles larger than 8.8 µm (for dry bulk material); x i,3 is a percentile of
the particle size distribution by mass.
Table 7 Total dust prediction functions for UNC dustiness tester, X A = moisture content of material
sample, X 0.8 = moisture content of a material at 80% relative humidity [6]
Dry bulk material log S UNC,dry = 0.93 exp (−0.15 K UNC )
Wet bulk material log (S UNC,wet X A ) = 0.50 + 0.44 (ε X A X 0.8 (x 90,3 − x 10,3 )/(x 90,2 −
x 10,2 ))