HEPA filters

March 2017

What is HEPA?
HEPA is an acronym for High Efficiency Particulate Arrestance or High Efficiency Particulate Air and is applicable to a specific type of air filters that stop between a minimum of 85% and a maximum of 99.999995% of all dust particles of 0.3 micrometres (microns), depending on the specific type of filter.

History and application
The HEPA filter was designed in the 1940s for the Manhattan Project as breathing filters to capture airborne radioactive contaminants and protect the US soldiers and atomic scientists. HEPA was commercialized in the 1950s, and the original term became a registered trademark and later a generic term for highly efficient filters.

Over the years, the filters are developed further to meet increasing demands for air quality in high-tech applications such as aerospace, pharmaceuticals, cleanrooms, operating theatres and quarantine departments in hospitals, health care, nuclear energy and electronics (manufacture of chips). HEPA filters can also be used with allergies to airborne allergens, such as house dust. The use of HEPA filters is required when removing asbestos.

HEPA classes
A HEPA filter is specified in European Standard 1822:2009 (EN1822) from the European Union. It contains several classes of HEPA filters:

HEPA class       Retention (total)     Retention (local)
H10                   > 85%                  ---
H11                   > 95%                  ---
H12                   > 99.5%               ---
H13                   > 99.95%              > 99.75%
H14                   > 99.995%            > 99.975%

The term "HEPA filter" only applies to filters that meet or exceed the above requirements. The Scanpart HEPA filters are class H12 and remove at least 99.5% of all particles from the exhaust air.


Use in vacuum cleaners
Nilfisk was the first company to put a HEPA filter in a vacuum cleaner. Nowadays, many vacuum cleaners use of HEPA filters as part of their filtration systems. This is beneficial for asthma and allergy sufferers, because the HEPA filter traps the fine particles (such as pollen and dust mite faeces) which trigger allergy and asthma symptoms. Filters with higher HEPA class ratings not only remove more particles from the air, they also remove smaller particles. Because of the extra density of a higher class HEPA filter, these vacuum cleaners require more powerful motors to provide adequate cleaning power.

Washable?
HEPA filters are made out of loosely and randomly interlaced fibres that are not built to stand up to any stress beyond that of a vacuum cleaner. Washing a HEPA filter will destroy it in most cases. Even when the filter seems to still be intact to the naked eye, its structure has been rendered useless. Cleaning an HEPA filter is also a dirty job, especially for somebody who is allergic. Therefore we do not recommend to use washable filters.

Replacement?
A not washable HEPA filter should be replaced every 6 months or at least once a year. Washable HEPA filters should routinely be washed every month and replaced every 2-3 years as needed.

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