Air quality needs vary across healthcare facilities, but the goal remains the same: protecting patients, their families and healthcare workers, as well as the critical processes that support patient care. From public lobbies and administrative offices to patient rooms, operating rooms and pharmacy cleanrooms, each space presents different risks. The right filtration strategy should reflect how the space is used, who may be exposed and the level of protection required.
Healthcare facilities address these differences by selecting filters based on how the space is used and the level of protection required.
Most patient treatment areas use a pre-filter followed by a high-efficiency final filter. Environments with the greatest clinical risk add a third stage of HEPA filtration to protect patients, visitors and staff.
In healthcare, the consequences of failure can be fatal. Between October and December 2025, six immunocompromised transplant patients at Sydney’s Royal Prince Alfred Hospital developed invasive Aspergillus infections during a nearby hospital redevelopment project. Two died. Health authorities were unable to positively identify a single conclusive cause, but adjacent construction work and a balcony posed the greatest risk. The hospital’s response included a deep clean of the transplant ward, upgrades to air filtration systems, and comprehensive air testing.¹
Why Healthcare Facility Air Is Different
Healthcare facilities care for people who are often more vulnerable to airborne particles and pathogens than the general population. Some patients are recovering from surgery. Others have weakened immune systems from illness, treatment or transplant procedures. This raises the bar for indoor air quality.
The Centers for Disease Control and Prevention has noted that individuals receiving high doses of chemotherapy, along with those receiving organ or stem cell transplants, face some of the highest risks from airborne microorganisms, including common environmental fungi.
Meeting those needs is not just best practice. Healthcare ventilation requirements are governed on a state-by-state basis in the U.S., with many states following ASHRAE Standard 170, Ventilation of Health Care Facilities, which establishes minimum ventilation and filtration requirements for many healthcare spaces. In many areas of a hospital, this means a two-bank filtration system with a prefilter followed by a high-efficiency final filter. The most critical spaces go a step further and require or recommend terminal HEPA filtration.
“The most effective healthcare filtration strategies recognize that every space has different requirements,” says Mark Davidson at Camfil. “Standard 170 follows a layered approach, allowing facilities to match filtration to the level of risk involved. In those spaces where the risk is highest, HEPA filters are required. These filters are often protected by high-efficiency filters upstream such as MERV 14 or MERV 16. “
The Three-Stage Filtration Train
Healthcare filtration works best when each filter performs a specific role within a complete system.
Stage one is the prefilter. Its job is to remove larger airborne particles before they enter the rest of the air handling system. Removing this material early protects the more valuable downstream filters from unnecessary loading and keeps equipment clean.
Stage two is the high-efficiency filter. This stage captures the finer particulate that the prefilter cannot. Most general healthcare areas use this as their final stage.
Stage three is HEPA filtration. HEPA filters are required where the risk of infection is highest, not only for the patient, but for visitors and staff as well. Rather than serving the entire building, HEPA filters are often installed in terminal housings nearest the diffusers.
Camfil’s product portfolio maps to each stage of this system.
The 30/30 Dual 9 Panel Filter serves as the prefilter. This MERV 9 pleated panel filter, also rated under ISO 16890 as ePM10 55%, features radial pleats and welded wire backing. It carries a 5-Star Energy Cost Index rating and is guaranteed to last 9 to 12 months in commercial use. Its role is to protect downstream high-efficiency and HEPA filters while keeping the air handler coils clean. A longer service life also reduces the number of filter changeouts.
The Durafil ES3 fills the high-efficiency stage. Available in MERV 13, 14, and 16 efficiencies, corresponding to ePM1 70% to 95% under ISO, it complies with ASHRAE 170 requirements for many patient care areas and also serves as the upstream high-efficiency stage before HEPA filtration in critical spaces. It offers the lowest life-cycle cost and the lowest average pressure drop of any comparable ASHRAE-rated high-efficiency filter.
Note on MERV notation: Camfil filters are also designated with MERV-A ratings under ASHRAE 52.2 Appendix J, which measures efficiency after conditioning and indicates a filter’s ability to maintain its efficiency rating. A MERV 13/13A rating for example, means the filter will maintain its MERV 13 performance for the duration of its service life.
For spaces that require the highest level of filtration, Camfil’s Megalam Panel Filters provide the terminal HEPA stage. These HEPA and ULPA mini-pleat panel filters deliver tested and certified efficiencies ranging from 95% at 0.3 micron to 99.99995% at the most penetrating particle size. For air handling units designed to hold box-style HEPA filters, Camfil offers the Absolute VG, a lightweight but exceptionally strong V-bank style HEPA filter with certified capture efficiency of 99.99% on 0.3-micron particles.
The Payoff: Safer Air and Lower Costs
A layered approach supports long-term operating efficiency alongside infection control.
A quality prefilter captures larger particulate matter before it reaches downstream high-efficiency and HEPA filters. It also extends the life of those higher-value filters and reduces replacement frequency.
Healthcare facilities run continuously and use significant energy to condition and move air. Filters with lower average pressure drops reduce the energy needed to circulate air, which drives down operating costs.
Longer-lasting filters mean fewer maintenance interruptions. In continuously operating facilities, every filter replacement takes staff time and creates potential disruption to critical care areas. Eliminating unnecessary replacements supports both operational efficiency and total cost of ownership.
What to Review in Your Facility
Healthcare facilities should periodically review their filtration strategy to make sure it still supports both operational requirements and applicable standards.
- Verify each space complies with the requirements within ASHRAE Standard 170
- Confirm that a prefilter protects every high-efficiency and HEPA filter bank
- Verify the seal and installation integrity of HEPA filters in critical spaces, not just the filter media
- Change filters based on pressure drop monitoring rather than a fixed calendar
- Maintain filtration records to support accreditation and infection control reviews
FAQ
What air filters do hospitals use?
Most hospitals use layered filtration systems. These consist of a prefilter followed by a high-efficiency final filter. Terminal HEPA filters are added to critical spaces such as high-risk procedure operating rooms and pharmacy cleanrooms.
What does ASHRAE 170 require for healthcare filtration?
ASHRAE Standard 170 establishes minimum ventilation and filtration requirements for many healthcare spaces. Two-bank systems are common in most areas, and terminal HEPA filters are recommended for the most critical environments.
Where is HEPA filtration required in a hospital?
HEPA filters are used in critical applications, including operating rooms designed for high-risk procedures, protective environment rooms, airborne infection isolation rooms and compounding pharmacy cleanrooms.
Is a high-efficiency filter the same as a HEPA filter?
No. High-efficiency filters are tested according to ASHRAE Standard 52.2 and are rated between MERV 13 – MERV 16. HEPA filters are tested according to one of three accepted standards: IEST RP-CC001, EN1822 or ISO29463. HEPA filters should be individually tested and labeled with the results of the test.
How often should healthcare filters be changed?
Filter changeout frequency should be driven by pressure drop monitoring. Pressure drop increases as the filter loads with dirt. Higher pressure drop forces the fan to work harder to supply the required volume of air, which increases energy costs.
Healthcare air filtration works best when every stage has a clear role. Combining prefiltration, high-efficiency filtration, and HEPA filtration where needed lets facilities match air quality to each space while improving operational efficiency.
To review the right filtration strategy for your healthcare facility, contact a Camfil Air Quality Expert or request a facility assessment.
Sources
¹ Sydney Local Health District statement, February 2026. Coverage: SBS News, “Two patients have died after a fungal outbreak at Sydney hospital,” February 26, 2026. https://bit.ly/4x5wyvo
The post How Healthcare Facilities Layer Their Air Filtration appeared first on Air Filters for Clean Air.
from Air Filters for Clean Air
