Ultra-low particulate air

Ultra-low particulate air (ULPA) is a type of air filter. A ULPA filter can remove from the air at least 99.999% of dust, pollen, mold, bacteria and any airborne particles with a minimum particle penetration size of 120 nanometres (0.12 μm, ultrafine particles). A ULPA filter can remove—to a large extent but not 100%—oil smoke, tobacco smoke, rosin smoke, smog, and insecticide dust.David A. John. Air-distribution design: HEPA or ULPA filtration. [https://www.thefreelibrary.com/Air-distribution+design%3A+HEPA+or+ULPA+filtration-a0348648011 Air distribution design HEPA or ULPA filtration] ASHRAE Journal, vol. 55, no. 5, May 2013 It can also remove carbon black to some extent. Some fan filter units incorporate ULPA filters. The EN 1822 and ISO 29463 standards may be used to rate ULPA filters.{{Cite book|url=https://books.google.com/books?id=z07ABAAAQBAJ&dq=iso+29463&pg=PA189|title=Fundamentals of Air Cleaning Technology and Its Application in Cleanrooms|first=Zhonglin|last=Xu|date=October 10, 2013|publisher=Springer Science & Business Media|isbn=978-3-642-39374-7 |via=Google Books}}{{Cite book|url=https://books.google.com/books?id=zWx2EAAAQBAJ&dq=en+1822+standard&pg=PA305|title=Hygienic Design of Food Factories|first1=John|last1=Holah|first2=Huub L. M.|last2=Lelieveld|first3=Frank|last3=Moerman|date=May 25, 2023|publisher=Woodhead Publishing|isbn=978-0-12-822619-3 |via=Google Books}}

Materials used in ULPA filters

Both high-efficiency particulate air (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:{{Cite web | title=IEST Recommended Practices | publisher=IEST | date=2007-12-03 | url=http://www.iest.org/RecommendedPractices/IESTRPCC001/tabid/9637/Default.aspx | access-date=2008-01-14}}

IEST-RP-CC001: HEPA and ULPA Filters,
IEST-RP-CC007: Testing ULPA Filters,
IEST-RP-CC022: Testing HEPA and ULPA Filter Media, and
IEST-RP-CC034: HEPA and ULPA Filter Leak Tests.

Specifications

class="wikitable"

!Efficiency

!EN 1822

!ISO 29463

!Retention (averaged)

!Retention (spot)

rowspan="3" |ULPA

|U15

|ISO 55 U

ISO 60 U

|≥ 99.9995%

≥ 99.9999%

|≥ 99.9975%

≥ 99.9995%

U16

|ISO 65 U

ISO 70 U

|≥ 99.99995%

≥ 99.99999%

|≥ 99.99975%

≥ 99.9999%

U17

|ISO 75 U

|≥ 99.999995%

|≥ 99.9999%

See also the different classes for air filters for comparison

References

External links

[http://www.sentryair.com/hepa-filter.htm ULPA Filter Efficiency Chart: Sentry Air Systems]
[https://web.archive.org/web/20161022055850/http://www.aafeurope.com/en/150/en1822 European Standard for EPA, HEPA & ULPA Filters] — EN 1822 [https://aafeurope.fr/fileadmin/user_upload/Products/20200729_AAF_Product_Quick_Reference_Guide__EN.pdf p. 6]
[http://www.electroiq.com/articles/cr/print/volume-15/issue-10/features/features/en-1822-the-standard-that-greatly-impacted-the-european-cleanrooms-market.html EN 1822: the standard that greatly impacted the European cleanrooms market]
[https://airhealth.in/knowledge/what-are-ulpa-filters-how-they-work-benefits-and-use Ulpa Filter Designs and How it clears the air]

Category:Filters

Category:Cleanroom technology