Understanding FFP2, KN95, N95, and Other Filtering Respirators
Quick Summary: Understanding Respirator Standards
Global Equivalents: N95 (US), FFP2 (Europe), KN95 (China), and P2 (Australia/New Zealand) are regional standards for filtering facepiece respirators that offer highly comparable levels of protection.
Filtration Performance: Despite minor differences in testing flow rates, all of these major standards require the mask to filter out at least 94% to 95% of airborne test aerosols (like NaCl).
The Comfort Balance: Respirator design hinges on "pressure drop" (breathing resistance). Manufacturers must balance a low pressure drop for breathing comfort with a high enough density to effectively trap particles.
The Seal matters (TIL): Standards like FFP2 and P2 measure Total Inward Leakage (TIL) to ensure the mask maintains a tight, safe seal around the face while the wearer is moving and performing tasks.
Filtering facepiece respirators (FFRs), often called disposable respirators, follow different standards around the world. Each standard sets out its own rules for how the masks should perform. In times of health emergencies, you’ll usually hear recommendations for models such as N95, FFP2, or their equivalents.
Here are some of the most recognised standards:
- N95 (United States)
- FFP2 (Europe)
- KN95 (China)
- P2 (Australia/New Zealand)
- Korea 1st class (Korea)
- DS2 (Japan)
While the test flow rates for inhalation and exhalation vary between these standards — ranging roughly from 30 to 160 L/min — the overall breathing resistance, or pressure drop, often comes out quite similar. This is because filters behave consistently: higher flow rates create more resistance, while lower flow rates reduce it.
Understanding Mask/Respirator Pressure Drop
A pressure drop simply means how much resistance the mask material gives to air passing through it.
- Lower pressure drop = air moves through the mask more easily.
- Higher airflow rate = breathing feels more comfortable.
But there’s a trade-off. If resistance is too low, the mask may not filter particles as effectively. That’s why respirator design always looks for balance — enough airflow for comfort, and strong filtration for protection.
*Japan JMHLW-Notification 214 requires an Inward Leakage test rather than a TIL test. Tested on human subjects each performing exercises.
Definitions:
- Filter performance – Measures how effectively the filter reduces concentrations of specific aerosols in the air that pass through it.
- Test agent – The aerosol generated during the filter performance evaluation.
- Total inward leakage (TIL) – The amount of a specific aerosol that enters the respirator facepiece through both the filter and face seal leakage while the wearer performs various exercises in a test chamber.
- Inward leakage (IL) – The amount of a specific aerosol that enters the respirator facepiece during normal breathing for 3 minutes in a test chamber. The aerosol used has a particle size (count median diameter) of approximately 0.5 micrometres.
- Pressure drop – The resistance air encounters as it moves through a medium, like a respirator filter.
Frequently Asked Questions:
- Q: What is the difference between N95, FFP2, and P2 respirators?
- A: N95 (US), FFP2 (Europe), and P2 (Australia/New Zealand) are regional certifications for filtering facepiece respirators. While their specific laboratory testing methods vary slightly, they all provide comparable clinical protection, filtering at least 94% to 95% of airborne particles.
- Q: Do N95 and KN95 masks filter the same amount of particles?
- A: Yes, both the N95 (United States standard) and the KN95 (Chinese standard) require a minimum filter performance of ≥ 95% against airborne test agents, offering highly similar levels of baseline particle filtration.
- Q: What does "pressure drop" mean in a respirator mask?
- A: Pressure drop measures the breathing resistance of the mask's filter material. A lower pressure drop means air moves through the mask more easily, making it more comfortable for the wearer, while a higher pressure drop indicates greater breathing resistance.
- Q: Why is Total Inward Leakage (TIL) important for face masks?
- A: Total Inward Leakage (TIL) measures the amount of hazardous aerosol that bypasses the filter and enters through the face seal while the wearer is moving. It is a critical metric to ensure the mask maintains a secure, protective seal during real-world activities.
- Q: How do respirator manufacturers balance filtration and comfort?
- A: Respirator design requires a strict balance between filter density and airflow. If breathing resistance (pressure drop) is too low, the mask will fail to filter particles effectively. Manufacturers must engineer materials that maximize clinical protection without severely restricting airflow.