Not all HEPA filters are created equal. Only by using the EN1822:2019 and ISO 29463 test standards can end users really identify whether a HEPA filter has been manufactured and designed to fit the clean air requirements of their workplace. The EN1822 standard has had many iterations dating back to its original inception in the 1990s. In the latest iteration of this standard, the test procedure for ISO 29463 has been included to ensure global acceptance of the test. Whether the HEPA filter is used for controlled environments like cleanrooms or as part of a system upgrade in a HVAC system or in a standalone air cleaner, you should always check that the filter has been individually certified to these standards.
Standalone HEPA air purification systems require 100% factory tests on their installed filters, just like other HEPA filters. These systems are usually put inside rooms and facilities where added protection is needed. They are used to supplement HVAC systems and remove airborne contaminants