ULPA filter
A step beyond HEPA, specified by particle size rather than by marketing. Worth it only for specialised work.
In detail
An ULPA — Ultra Low Penetration Air — filter removes particulates down to 0.12 microns, against the 0.3 microns a HEPA filter is defined by. The conservation guidance that names it is careful about when that difference is worth having: ULPA is described as appropriate for specialised projects rather than as a general upgrade. That restraint is the useful part. Finer filtration costs airflow, and a vacuum that filters superbly and moves little air is worse at the job than one that filters well and lifts the dirt. The reason to reach for ULPA is a specific fine contaminant, not a general wish for the best available number. Like any capture filter it fails by loading rather than by breaking, and the failure is invisible from outside.
What works
ULPA filter is effective against Dust Supported
Why
- ULPA filter is explained by Clogging the thing that does the work
Sources for this page
Sources
Conserve O Gram 1/6: Choosing a Museum Vacuum Cleaner
National Park Service, US Department of the Interior, 2003 · Government or regulator
Relied on for: That ULPA filters remove particulates down to 0.12 microns and may be appropriate for specialised projects, against HEPA's 0.3 micron specification. (states this directly)