The most common HEPA filter testing method is the “aerosol photometry test.” This test has existed since the 50s and is highly accurate. The way it works is a technician will spray a dispersed oil particulate (DOP) over the surface of the filter.
The best way to tell when your HEPA filter needs replacing is with a separate air quality monitor. When you first install your air purifier, your air quality monitor should show that your purifier is doing a good job of cleaning your air.
Commercial HEPA filters for a non-governmental project must still be tested - both prior to shipping and again in-situ - in order to qualify as HEPA-certified filters. This testing requires specialty equipment, materials, and personnel. The cost of such testing can be as much as $300 per filter.
Using a photometer, the lead engineer will measure upstream concentration of aerosol, calibrating as required. The DOP may need to be increased or decreased. Downstream penetration of aerosol will then be measured using a photometer, scanning the filter face with overlapping strokes at a speed no greater than 5cm/s.
If you notice a decrease in airflow from your air purifier, it could indicate that the HEPA filter is clogged and in need of replacement. A decrease in airflow can lead to increased energy consumption and reduced effectiveness, as pollutants and allergens are no longer being removed from the air.
The average lifespan of HEPA filters can vary significantly depending on their usage, environment, quality, and maintenance, as previously discussed. However, as a general guideline, HEPA filters typically last between 6 months to 3 years before needing replacement.
Bottom Line: How to Clean and Wash a HEPA Filter? Vacuuming HEPAs may improve performance, but the effect is small. Washing HEPAs strongly decreases performance. We do not recommend washing HEPAs.
High Efficiency Particulate Air (HEPA) Filter: A throwaway, extended-media, dry type filter with a rigid casing enclosing the full depth of the pleats. The filter shall exhibit a minimum efficiency of 99.97% at a test aerosol diameter of 0.3 micrometer.
HEPA and ULPA filters can tolerate some humidity. Humidity higher than 95%, however, can cause the filter media to plug, resulting in failure (EPA, 1991).
To maintain the proper functioning of your filters, your facility should conduct testing and regular maintenance. When should HEPA filters be tested? Once the filter is installed, integrity test should be conducted to make sure it is functional. Besides, integrity test is also a routine for cleanroom maintenance.
Whole house air filtration offers a thorough solution for indoor air quality, but the lack of options and higher costs might be a dealbreaker for some. Doesn't filter smaller particles due to the need for airflow. Requires an HVAC technician for installation. Has a higher initial cost.
Unless approved otherwise, HEPA filters are tested at minimum once every 12 months, except those installed in ISO Class 5 facilities, which are tested every 6 months. If testing detects a leak in the HEPA filter, repairs must follow an approved patching procedure based on the IEST RP-CC034.
This is especially true if a HEPA filter becomes clogged, as both the density of the filter media itself and the trapped particles will prevent air from moving through the system. For these reasons, it is important to change filters as recommended and to check to make sure the filters aren't clogged.
The first is related to their cost. A high-quality HEPA filter can cost anywhere from a few hundred dollars up to several thousand depending on the size and model and the area to be covered. Secondly, they need to be regularly maintained and replaced in order to keep them working properly.
There are many indoor air monitors available on the market, including the Airthings Wave Plus and the uHoo Smart Air Monitor. Alternatively, you can buy another type of smart device that has air quality monitoring functionality, such as a tech-enabled air purifier, smart thermostat or indoor home security camera.
The HEPA filter integrity test is typically performed on supply air or exhaust air HEPA filters using a photometer to scan the filter surface for pinhole leaks that could allow the transmission of contaminant particles that would be unacceptable in a critical application.
Part of the reason that HEPA filters are so rarely used in HVAC systems is that they are extremely restrictive in terms of airflow. This means that the system needs to be extremely powerful and use additional fans in order to properly draw air through the HEPA filter and circulate it throughout the room or building.
Some regions, like the ones more affected by fire season, may need to change their HEPA filter more than twice every year. Some signs to watch out for are: Dirt and dust are accumulating around your air vents. Your electricity bill has gone up for no reason.
PAO PAO or Poly Alfa Olefin is a monoor poly-dispersed test aerosol of sub- micron particles, generated to challenge (evaluate integrity of) of HEPA filters.
A HEPA filter marketed as “permanent” should be cleaned by gently using a vacuum cleaner to suck away dust and debris from the surface of the filter. Water typically should not be used on these types of filters.
If you see a visible buildup of dust or particles on a HEPA filter (it may look gray or dirty) or observe reduced airflow through your portable air purifier, you may assume that's an indication the HEPA filter needs cleaning.
HEPA filters for home use with a portable air purifier or central AC should be changed every 6 to 12 months. However, how long a HEPA filter lasts depends on a few variables. Your HEPA filter may need to be replaced more often in some circumstances.
HEPA filters can be vacuumed, but in the process, the HEPA filters are designed to trap particles up to 99% accuracy; this means that it's near impossible to vacuum all of the remaining particles and bacteria from the filter. You may end up damaging the filter by washing it, as it is extremely fragile.