October 11, 2024

Respirators – but which ones? | Secure knowledge

Since there is currently uncertainty about which protective masks offer protection against which dangers and which masks should be used, here you will find an overview of the use and benefits of protective masks in different areas of application.

above: three FFP masks with exhalation valve; bottom left: FFP mask without exhalation valve, bottom right: MNS mask (surgical mask). [Credit: LWTAF]

Employers have an obligation to protect their employees from health effects caused by occupational contact with solid (particles) Face mask or liquid substances (aerosols and larger droplets). A distinction must be made between medical personnel and all other workers, as they are confronted with different risks.

When breathing, talking, coughing, sneezing, etc., smaller or larger amounts of secretion droplets are released from the mucous membranes in the mouth and nose. The majority of the droplets have a diameter between 0.5 μm and 12 μm and especially the larger particles can contain microorganisms. The droplets can spread through the air and thus reach sensitive areas such as an open surgical wound or sterile equipment and contaminate them.

For this reason, medical face masks, also called mouth-nose masks (MNS masks), hygiene masks or surgical masks (surgical masks), are usually used in the medical field.

Medical face masks, which are intended for use in operating rooms and healthcare facilities with similar requirements, are designed to protect the entire working environment rather than the wearer. The requirements and test methods for these masks are regulated in ÖNORM EN 14683. This standard describes two types of medical face masks with the associated levels of protection:

  • Type I masks: Type I medical face masks are used on patients to reduce the risk of spreading infection, especially in epidemic or pandemic situations.
  • Type II masks: These are generally intended for use by healthcare professionals in an operating room or other medical facility with similar hygienic requirements.

There are also differences in the bacterial filter performance that these masks must meet in a standardized test: for type I masks, it is ≥ 95%, for type II masks ≥ 98% of all bacteria that need to be filtered.

If the medical or nursing staff has to deal with patients who are infected with the coronavirus, it makes sense for the medical or nursing staff to wear a particle-filtering respirator mask (FFP = Filtering Face Piece) of at least type FFP2 (better FFP3 masks) to protect against their own infection, which patients also wear a surgical mask of at least type I (better type II).

Apart from the medical field of application, only so-called particle-filtering half masks are used. The requirements for, as well as the testing and marking of particle-filtering half masks are regulated in ÖNORM EN 149. A distinction is made between the three filter classes FFP1, FFP2 and FFP3, which must meet the following filter performances:

  • FFP1: ≥ 80% of particles in the air up to 0.6 μm
  • FFP2: ≥ 94% of particles in the air up to 0.6 μm
  • FFP3: ≥ 99% of particles in the air up to 0.6 μm

Important: Particle-filtering respirators protect against particles, but not against gases and vapors. The masks are usually made entirely of filter material in several layers and are optionally equipped with an exhalation valve. This facilitates exhalation by exhaling the exhaled air directly through the valve and not through the filter material. An important feature for the wearing comfort of the mask is the breathing resistance, i.e. the resistance when inhaling and exhaling, which the wearer clearly perceives. Problem: (In)tightness of the masks

Depending on the manufacturer, the masks have a specified size and shape. However, since every person has an individual face shape, leaks occur when wearing the mask if it does not fit optimally. The total leakage of the mask results from the facial leakage, the valve slip (for masks with an exhalation valve) and the filter passage of the filter body. For all the air inhaled, the proportion of the “harmful” ambient atmosphere in

  • FFP1 masks max. 25 %
  • FFP2 masks max. 11 %
  • FFP3 masks max.   5 %

For male mask wearers, it is therefore enormously important that they are shaved as well as possible in order to enable an optimal tight fit. If this tight fit of the mask is not given, it cannot fulfil its protective function.

Purpose and protective effect?… protect the environment of the wearer from drops in their exhaled air and the wearer from penetration of liquid splashes

… protect the wearer from inhaling the smallest particles and drops.Suitable for whom? Medical and nursing staff – to protect patients

WITHOUT exhalation valve and if approved as a medical device: for medical and nursing staff as well as rescue and emergency services in direct contact with infected persons

WITH exhalation valve: for all non-medical applications to protect against dusts and aerosols with viruses and bacteria. Only if the person carrying the patient expects to spread pathogens. For self-protection, the general hygiene measures and keeping a distance of 1 meter, better 2 meters, are sufficient.Sealing effect of the mask?Does not seal when used correctlyonly small leaksDuration of use? Dispose of as soon as the mask is moistened, but at the latest after the end of useFor a maximum work shift of 8 hours, unless the mask is suitable for reuse (see instructions for use)

Table: Comparison of the masks based on the DGUV poster: Protective masks – what is the difference? (MNS = mouth-nose mask, FFP = Filtering Face Piece) Don’t forget hygiene measures!

Even if protective masks are worn, the following hygiene and behavioral measures must also be observed:

  • Maintain respiratory hygiene (sneeze or cough into the crook of your arm or use a handkerchief, which is then discarded immediately)
  • Do not forget to wash your hands thoroughly (even BEFORE putting on the mask).
  • Don’t grab your face.
  • Even with mask at least 1 meter, if possible 2 meters, keep distance to other people! (Note on FFP masks: If an infected person uses an FFP mask with an exhalation valve, the environment is not adequately protected from that infected person. The exhaled valve usually deflects the exhaled air downwards towards the ground, but does not filter it.)
  • Do not touch the mask while wearing.
  • As soon as the mask is soaked, it must be changed immediately and must not be reused!
  • Wash hands BEFORE AND AFTER removing the mask.
  • Since the mucous membranes serve as a gateway for most viruses that are transmitted via droplet infection, these viruses can also penetrate the body, e.g. via the conjunctiva. Therefore, the use of additional eye protection, even better an additional face protection, makes sense.
  • If necessary, use appropriate disposable protective gloves.

Can DIY masks protect?

The self-made “do-it-yourself” (DIY) masks used in the private sector, made of fabric or similar material, as well as conventional scarves offer little protection against infection. At present, however, their use is helpful because with these DIY masks a wearer (e.g. when coughing or sneezing) naturally endangers their own environment a little less. However, the wearer can only protect himself to a small degree against droplet infection by using such aids because the material used is too coarse and has little filtering effect. For everyday professional life, “DIY” masks and aids are therefore completely unsuitable as “protection”. However, as long as no ‘better’ masks are available for the private sector, the use of DIY masks, e.g. for shopping, is still helpful there!

(Article published on 02.04.2020)