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Chapter 6: Maintaining Your Filtered Enclosure
3. Re-install the new carbon filter with the gasket down.
Replace the upper diffuser screen, clips and two screws.
4. The weight of the carbon filter with the gasket down will
compress the gasket.
Calculating Odor Control 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 Odor Control carbon filters for the filtered
enclosures 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).
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
=7.8 weeks before filter saturation
=.17 ml/min