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 ...

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 gametop ...

mold A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not ...

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 am ...

and any airborne particles with a minimum particle penetration size of 120

nanometre 330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer ( American spelling) is a unit of length ...

s (0.12

µm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...

, ultrafine particles). A ULPA filter can remove (to a large extent, not 100%) – oil smoke, tobacco smoke, 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 in ...

, insecticide 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 units 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: *

IEST The Institute of Environmental Sciences and Technology (IEST) is a non-profit, technical society where professionals who impact controlled environments connect, gain knowledge, receive advice, and work together to create industry best practices. ...

-RP-CC001: ''HEPA and ULPA Filters'', *

-RP-CC007: ''Testing ULPA Filters'', *

-RP-CC022: ''Testing HEPA and ULPA Filter Media'', and *

-RP-CC034: ''HEPA and ULPA Filter Leak Tests''.

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 {{tech-stub

Materials used in ULPA filters

Method of functioning

See also

References

External links