Filter
Top Products
59
Chapter 6: Maintaining Your Filtered Enclosure
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
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
Initial Certification
The filtered enclosure has been certified at the factory for an
inflow velocity of 90±10 fpm along with the HEPA Filter Leak
Test. The filtered enclosure should be certified for the proper
inflow velocity required by your Safety Officer. It is also a
conservative recommendation to perform the HEPA Filter Leak
Test again should there be any damage caused during transport.
Re-Certification
Under normal operating conditions, the enclosure should be
recertified at least annually if serviced. The certifier should
perform the following tests.
• Inflow Velocity Test
• HEPA Filter Leak Test
In addition, the following tests should also be performed at the
user’s discretion: