Labconco Protector 3930000 User Manual page 59

Calculating Carbon Filter Life
Labconco developed a modeling program to estimate the filter life for
typical carbon filters. Since filter life is dependent on the chemical used,
the airflow, filter size, and the dwell time, refer to the Chemical Guide for
the Paramount® Filtered Enclosure. The estimated life for carbon filters
for the Protector Work Stations with integral blower is conservatively
calculated at 50% or half of the published values for the Paramount in the
Chemical Guide. For example, if you use isopropyl alcohol to disinfect
and use approximately 100 ml per week during 2 hours of use per day
then follow these steps to calculate the concentration in parts per million
(ppm). Important: Two filters are always required for operation. If mixing
filter types, then use 25%.
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
week 10 hours use
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 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
6. These values are for two organic vapor filters. If mixing the filters
with formaldehyde or ammonia, then use 25% instead of 50%.
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Chapter 6: Maintaining Your Enclosure
X 10 hours =
600 minutes 600 minutes
= 7.8 weeks before filter saturation
100 ml lost
= .17 ml/min
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