Filter Handling and Exchange
Post Collection Weighing
3-10
Partisol 2000
i
and Partisol 2000
i
-D Instruction Manual
Thermo Fisher Scientific
4.
Place the petri dish cover under
the bottom half of the dish.
5.
Place a paper towel over the open petri dish during equilibration.
6.
Record the filter number, relative humidity, temperature, and date and
time at the beginning of this post-collection equilibration.
7.
Equilibrate each filter for at least
24 hours under the following
conditions:
The equilibration room must be held at a constant relative humidity
between 30% and 40%, with a variability of not more than ±5%
relative humidity.
The equilibration room must be held at a constant temperature
between 20 °C and 23 °C, with a variability of not more than ±2 °C.
Use the following procedure to weigh the 47 mm filters after sampling.
1.
Ensure that the filters have been equilibrated for at least 24 hours
before weighing.
2.
Filters must be weighed on a microbalance with a resolution of at least
1 g (0.001 mg). Ensure that the balance has been allowed to warm up
before weighing filters.
3.
Remove the filter from its petri dish.
4.
Weigh each filter at least once (three times recommended), recording
the mass in grams (
Figure 3–10
). The average mass reading is the final
filter weight, W
f
(g).
5.
Return the filter to its petri dish, place the petri dish cover over it and
store it for archival purposes.
6.
Document the relative humidity, temperature, and date and time of the
post-collection weighing.
7.
The “zero” reading of the microbalance should be verified between each
filter weighing.
Post Collection
Weighing
