All You Need to Know About N95 Respirators

Posted on the 20th of Aug 2020 by Westlab

The N95 respirator has fast become the face mask of choice for many Healthcare professionals and is widely considered to be the ultimate in protection against infectious aerosols.

But what is an N95 respirator and how do we determine the suitability and compliance criteria we need to comply with? The article below helps to summarise the key points:

What is a N95 respirator?

The Therapeutic Goods Association (Australia) defines it as ‘A filtering facepiece respirator (FFR) that is designed to form a very close seal around the nose and mouth, protecting the wearer from exposure to airborne particles including pathogenic biological airborne particulates such as viruses and bacteria. N95 respirators have been tested for particulate filtration to ensure they remove a minimum of 95% solid and liquid aerosols that do not contain oil. N95 respirators are a single-use item.‘

Further to this, Surgical N95 respirators are of a similar structure and design to standard N95 respirators and therefore meet the same testing requirements to achieve a minimum 95% filtration against airborne particulates, but have also been tested for fluid resistance against penetration by synthetic blood under different pressures, such as may occur during certain high-risk medical procedures.

N95 respirators are also often compared to P2 respirators which are also particulate filter respirators that provide similar protection from the airborne or aerosol spread but are designed, manufactured and tested to different, although comparable, standards. For the purposes of reducing exposure to COVID-19, both P2 and N95 respirators can be used interchangeably.

What standards do we need to comply with?

Filtering facepiece respirators (FFR), (also known as disposable respirators), are subject to various regulatory standards around the world. These standards specify certain required physical properties and performance characteristics in order for respirators to claim compliance with the particular standard required. During pandemic or emergency situations, health authorities often reference these standards when making respirator recommendations, stating, for example, that certain populations should use an “N95, P2, or similar” respirator. Below is a list of the better known global standards:

N95 (United States NIOSH-42CFR84)
FFP2 (Europe EN 149-2001)
KN95 (China GB2626-2006)
P2 (Australia/New Zealand AS/NZS 1716:2012)
Korea 1st class (Korea)
ASTM F1862/ISO 22609 (Blood Penetration)
ASTM F2101-14 or EN 14683:2014 (Filtration Efficiency and Differential pressure)

The NIOSH Standard

In the U.S., respirators are tested and certified by the U.S. National Institute of Occupational Safety and Health (NIOSH). NIOSH tests and certifies respirators based on their physical and performance characteristics, including filtration efficiency. For example, N95-rated filtering facepiece respirators have a filtration efficiency of at least 95% against non-oily particles when tested using the NIOSH criteria. The particles used to test the filtration are in a size range that is considered the most penetrating. Therefore, the test methods ensure that the filter media can filter particles with at least 95% efficiency.

NIOSH has currently established nine classifications of approved particulate filtering respirators based on a combination of the respirator series and efficiency level. The first part of the filter’s classification indicates the series using the letters N, R, or P to indicate the filter’s resistance to filtration efficiency degradation when exposed to oil-based aerosols (e.g., lubricants, cutting fluids, glycerine, etc.).

N for not resistant to oil. Used when oil particulates are not present. Tested using sodium chloride particles.
R for resistant to oil. Used when oil particulates are present and the filter is disposed of after one shift. Tested using dioctyl phthalate (DOP) oil particles.
P for oil-proof. Used when oil particulates are present and the filter is re-used for more than one shift. Tested with DOP oil particles.

Australian Requirements

In Australia, the AS/NZS1716:2012 standard is the minimum expectation for surgical respirators. In recent times it has become increasingly important to test for Fluid resistance against blood penetration under different pressures. Should your requirement involve close contact with the patient or be classed as a high risk medical/infectious procedure, then it is vital that this criterion is met to protect frontline healthcare workers. The expectation is that a barrier level of 160mm Hg is achieved (ISO22609). This test needs to be conducted on the material and the seams to ensure a leakproof seal against airborne particles.

All surgical respirators are regulated by the TGA under the Therapeutic Goods Act 1989 and will need to be included in the ARTG before they can be supplied. As a further safeguard, manufacturers may also test to Bacterial filtration efficiency (BFE) and Differential Pressure (Delta P). When choosing which standard/s apply to each device, the following should be taken into consideration:

intended purpose of the device
environment in which it is likely to be used
likely users of the device; and
generally acknowledged state-of-the-art.

A comparison is included below on the key criteria of a P2 vs N95 mask:

10 Key Questions When Purchasing Respirators

What is the intended purpose of the respirator – is it being used in high risk or infectious areas?
What are the local requirements in terms of compliance?
Are there certificates and test reports that document this?
Do these link directly with the product – references to batch numbers, product codes etc?
Has it been locally certified – TGA, FDA, etc?
Have samples been evaluated if required?
Is it supplied in user-friendly packaging?
Is the supplier a trustworthy and well-known provider to healthcare? (there are numerous ‘pop-up’ suppliers with inferior/non-compliant product)
Is the product available immediately or is there an extended lead time?
Are there bulk volume discounts available – can you consolidate volumes?