ULPA is an acronym for "Ultra-low Penetration Air (filter)". An ULPA filter can remove from the air at least 99.999% of
dust
Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Dust in homes ...
,
pollen
Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametophyt ...
,
mold
A mold () or mould () is one of the structures certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal seco ...
,
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
and any
airborne particles
Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The te ...
with a minimum particle penetration size of 120
nanometre
330px, Different lengths as in respect to the molecular scale.
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re ...
s (0.12
µm,
ultrafine particle
Ultrafine particles (UFPs) are particulate matter of nanoscale size (less than 0.1 μm or 100 nm in diameter).
Regulations do not exist for this size class of ambient air pollution particles, which are far smaller than the regulated PM10 and P ...
s). A ULPA filter can remove (to a large extent, not 100%) – oil smoke,
tobacco smoke
Tobacco smoke is a sooty aerosol produced by the incomplete combustion of tobacco during the tobacco smoking, smoking of cigarettes and other tobacco products. Temperatures in burning cigarettes range from about 400 °C between puffs to abo ...
, rosin smoke,
smog
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words ''smoke'' and '' fog'' to refer to smoky fog due to its opacity, and odor. The word was then inte ...
,
insecticide
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to b ...
dust.
[David A. John. Air-distribution design: HEPA or ULPA filtration.]
Air distribution design HEPA or ULPA filtration
ASHRAE Journal, vol. 55, no. 5, May 2013
It can also remove
carbon black
Carbon black (subtypes are acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal and coal tar, vegetable matter, or petroleum products, including fuel oil, fluid ...
to some extent.
Some
Fan filter unit
A fan filter unit (FFU) is a type of motorized air filtering equipment. It is used to supply purified air to cleanrooms, laboratories, medical facilities or microenvironments by removing harmful airborne particles from recirculating air. The units ...
s incorporate ULPA filters.
Materials used in ULPA filters
Both HEPA and ULPA filter media have similar designs.
The filter media is like an enormous web of randomly arranged fibres. When air passes through this dense web, the solid particles get attached to the fibres and thus eliminated from the air.
Porosity is one of the key considerations of these fibres. Lower porosity, while decreasing the speed of filtration, increases the quality of filtered air. This parameter is measured in pores per linear inch.
Method of functioning
Physically blocking particles with a filter, called sieving, cannot remove smaller-sized particles. The cleaning process, based on the particle size of the pollutant, is based on four techniques:
[
* Sieving
* Diffusion
* Inertial impaction
* Interception
A number of recommended practices have been written on testing these filters, including:]
See also
* High-efficiency particulate arrestance (HEPA)
* Minimum efficiency reporting value (MERV)
* Microparticle performance rating (MPR)
References
External links
ULPA Filter Efficiency Chart: Sentry Air Systems
European Standard for HEPA & ULPA Filters
nbsp;— EN 1822
* ttps://airhealth.in/knowledge/what-are-ulpa-filters-how-they-work-benefits-and-use Ulpa Filter Designs and How it clears the air
Filters
Cleanroom technology
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