Steps for calculating ppm and filter life – Labconco XPert Filtered Balance Stations 3962622 User Manual
Page 53
Chapter 6: Maintaining Your Filtered Enclosure
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Steps for Calculating PPM and Filter Life
1. Determine the amount of the proposed chemical lost to evaporation over a
given amount of time. For example, if you use isopropyl alcohol and lose
approximately 100 ml per week during 2 hours of use per day.
2. Convert the amount lost into ml/min. For this example:
100 ml X 1 week X 10 hours = 100 ml lost
week 10 hours use 600 minutes 600 minutes
3. Convert ml/min to PPM by multiplying ml/min by the conversion factor
found in the second to the last column on the right. For isopropyl alcohol
.17 x 41 = 7.0 PPM.
4. Find the PPM value on the chart that comes closest to the value you just
calculated in step #3. In this example, round up to 10 PPM, which is close to
the calculated 7.0. We may approximate the filter life to be around 155 hours
of actual use, but use 50% of this for the Odor Control filters or 78 hours.
5. Insert the estimated filter life into the estimated usage to determine how
long filters will last.
78 hours filter life
10 hours per week use
Formaldehyde only
For formaldehyde, use 10% of the impregnated carbon weight. Formalin is 37%
formaldehyde by weight. The density of formalin is 1.08 g/ml.
Model
Size
Filter Size
Pounds of
Formasorb Carbon
Adsorbed weight of
Formaldehyde
Adsorption Volume of Formalin
2'
18 x 18 x 1
7.0
0.7 lbs./318g
796 ml
3'
30 x 18 x 1
12.0
1.2 lbs./545g
1364 ml
4'
42 x 18 x 1
16.8
1.68 lbs./763g
1910 ml
5' (2 ea.)
24 x 18 x 1
19.0
1.9 lbs./858g
2148 ml
6' (2 ea.)
30 x 18 x 1
24.0
2.4 lbs./1085g
2716 ml
Ammonia only
For ammonia, use 10% of the impregnated carbon weight. Assume use of a 50%
solution of ammonia for these calculations.
Model Size
Filter Size
Pounds of
Ammonasorb II
Carbon
Adsorbed weight of
Ammonia
Adsorbed Volume of 50%
Ammonia Solution
2'
18 x 18 x 1
9.2
0.92 lbs./418g
836 ml
3'
30 x 18 x 1
13.5
1.35 lbs./613g
1226 ml
4'
42 x 18 x 1
18.9
1.89 lbs./859g
1718 ml
5' (2 ea.)
24 x 18 x 1
21.4
2.14 lbs./967g
1934 ml
6' (2 ea.)
30 x 18 x 1
27.0
2.71 lbs./1220g
2440 ml
=7.8 weeks before filter saturation
=.17 ml/min