Air filters for indoor environments: Interlaboratory evaluation of the new international filter testing standard ISO 16890

Abstract

Electret filters are widely used in HVAC systems to decrease particulate matter in indoor environments. The previous standard in Europe for testing air filters for general ventilation was EN 779. In July 2018, it was replaced by the new international standard ISO 16890. One major change is the discharging process: It is now performed by treating the filters with saturated isopropyl alcohol (IPA) vapor. The process is intended to simulate a worst‐case scenario of the filtration efficiency due to the reduction of the electret effect. These minimal efficiencies are a principal part of the filter classification. Therefore, two round robin tests with different filter classes (F9 and F7 according to EN 779) and up to eleven participants were carried out to evaluate the new test method by comparing the filtration efficiencies and pressure drops before and after the IPA treatment. Pressure drop measurements showed no mechanical altering of the material due to the discharging process. The calculated filter classes had a maximum deviation of 5%. Even with different equipment, the results indicate that the new ISO 16890 seems to be a viable test standard and a decent replacement for previous national standards.

Antibacterial Polymeric Nanofibers from Zwitterionic Terpolymers by Electrospinning for Air Filtration

“…In addition to the conventional mechanical method used to trap PM, electret filters can absorb submicron-sized airborne dust particles by electrostatic attraction, so they have the advantage of offering high filter efficiency and less air resistance to airflow. Electret filters are used extensively in air-conditioning (HVAC) systems, in ventilating, and in heating for residential and commercial buildings to alleviate the effect of PM in indoor environments . To determine the minimum filtration efficiency of electret filters, different artificial electric discharging methods are employed to eradicate electrostatic effects.…”

“…IPA is well known to eliminate electret filter charge. Our synthesized nanofiber mats were subjected to saturated IPA vapor treatment for 24 h as directed by ISO 16890, a new international filter testing standard . Almost no changes in filter efficiency and thickness of the filter medium were observed: 96.5% before and 96.4% after the saturated IPA vapor treatment.…”

Effect of surface charge density on electret filters charge degradation by organic solvent exposure

“…To determine the surface charge density using equations ( 1) to ( 6), the collection efficiencies of uncharged particles for both charged and uncharged filters are necessary. Because it is difficult to obtain an uncharged filter with the same internal structure as the charged filter, the uncharged filter was prepared by exposing the electret filter to IPA droplets according to the methodology outlined by Kim et al [24], Xiao et al [25], and Sachindou et al [41]. Previous studies indicate that IPA plays a role in faster and more effective charge degradation than other organic solvents [25,42].…”

“…[41] mentioned that the electrostatic charges in the electret filter were neutralized by saturated IPA vapors under the ISO 16890 standard [41]. However, both droplets and vapors are present when the vapor saturation ratio exceeds unity [45].…”

Evaluation and risk communication of effects of alcohol exposure on disposable procedure masks and portable air purifiers

“…Generally, non-woven HEPA has a lower pressure drop than glass fiber HEPA, making it easier to achieve a large airflow in a compact housing area, hence, rendering it suitable for use in the compact Japanese houses. However, like masks, electret is deactivated upon exposure to alcohol (Schuldt et. al.…”