HEPA filters are one of the most widely-known methods of air cleaning.
In fact, when most people think of an air cleaner, they think of a HEPA
air filter. HEPA filters all have limitations that should considered before deciding on an air cleaner to
purchase.
The History of HEPA: HEPA is an acronym for ‘High Efficiency Particulate Air Filter’, used in U.S. military specifications beginning around World War II. The precise definition of a HEPA varies somewhat from country to country,
many units claiming to be
HEPA air filters do not adhere to true HEPA standards.
Hospitals, doctors offices and labs use HEPA filtration systems to clean
their air. Many use HEPA filtering in addition to a UV light air filter.
HEPA filters work great on those with severe allergies or a mold and mildew
problem. They do cost more than ionic and ozone air purifiers, however they
are more efficient and also have government scientific studies to support
their effectiveness.
A conventional HEPA filter consists of a
sheet of
medical grade filtration
paper which is pleated with corrugated aluminum
separators between the pleats. This forms the
HEPA air filter element, which is then bonded into a rigid frame using a polyurethane compound.
Drawbacks to HEPA: HEPA filters cannot be cleaned to remove particulate and dust loading and must be replaced as a complete assembly
or as individual filters. As the particle load increases, so will the resistance to flow and the pressure drop across the
filter causes it to be
less effective (less air will go through
the filter, however, the filtration will be more efficient).
Many HEPA air filter units also do not
account for air that leaks around the edges of the filters, this
sealing problem accounts for more inefficiency. Some manufacturers will void your warranty on filtration systems if you do not replace the filter according to a
their specified schedule. Failure to change the HEPA air filters
when they specify can cause the fan motor to work too hard and
burn out prematurely.
IQAir
and NQ Clarifier systems use true HEPA filters and have superior total system performance. Do
not be fooled by cheap imitations that claim to use HEPA filters but do not
offer HEPA performance!
|
