ULPA (Ultra Low Penetration Air) is a filtering
efficiency specification for filters used in
environments like pharmaceutical labs wherein the
highest degree of clean air must be maintained.
An ULPA filter must retain all particles as small
as 0.12 µm
in size at an efficiency rate of 99.999%. The phrase "as
small as" means that if all particles were that
small, it would still have that efficiency. This
should not be confused with the phrase "down to"
which may mean a mixture of particle sizes for
the stated efficiency.
The Nilfisk Portable Dust
Collector is an example of a commercial vacuum
cleaner which can be equipped with a Certified
ULPA filter. Due to its air tight seals, it
actually meets the ULPA specification for net
filtration. Certified ULPA filters, like those
used by Nilfisk, are tested and marked with a
certification number which gives the user the
assurance that the ULPA specification is actually
being achived by the filter. See also our article
on Filtration Efficiency - HEPA,