Respirator use: to shave, or not to shave, that is the QUESTION

Common Requirement on Facial Air

Powered Air Purifying Respirator (PAPR) for beards

 The Question here refers to respiratory protection when wearing a mask or a respirator.

Here, the ‘respirator’ can be categorized as an Air Purifying Respirator (APR) and a Powered Air Purifying Respirator (PAPR).

Within PAPRs, we have Tight-fitting PAPRs and Loose-fitting PAPRs.

Here, ‘tight-fitting’ means a tight facial seal between the respirator and the skin as intended by design to prevent leaks; and ‘loose-fitting’ means a partial seal between the respirator and the skin as intended by design to relax the fitting allowing some leaks.

Typical tight-fitting respirators involve an elastomeric facial cushion, and typical loose-fitting respirators involve a helmet, a visor, or a hood.

Except for Loose-fitting PAPRs, clean-shaven is the common requirement when it comes to wearing a tight-fitting respirator, especially a paper mask or an APR.

The reason is simple:

you want all the hazardous contaminants to be blocked by the filter media coming with the mask or respirator. To ensure that, you want to make sure there is no gap between the mask/respirator and your facial skin. With facial hair, such as a beard, your mask or the respirator cushion will contact your beard first instead of your skin, leaving a gap for the contaminants to bypass the filter media to be sucked under negative pressure in the mask during inhalation.

So yes, with a negative pressure mask or respirator (APR), you must be clean-shaven to achieve the expected protection, and there is no question here, period.

However, there may be a danger of misconception here that loose-fitting PAPRs are suitable for bearded wearers without considering the limitations. The fact is that the suitability is highly conditional and can be affected by several factors for a given application, such as:

• How long is the facial hair and where is it located?
• How powerful is the loose-fitting PAPR being used?
• How is the airflow controlled? Will the flow get less when the built-in battery level is low?
• How heavy is the physical work demanding on your breathing?
• How dense are the contaminants?
• What is the maximum exposure limit for the contaminants?

Most of these factors are related to the single most essential characteristic of PAPRs: Positive Pressure in the mask/breathing zone. As long as positive pressure is maintained all the time, there will be no leak issue from facial hair, as the air tends to be pushed out of the mask instead of being sucked in.

Now the question comes as to how positive pressure can be always maintained.

In a theoretical scenario, as long as the airflow generated from the blower in the PAPR is not less than the inhaled flow, positive pressure can be maintained. But in practice, for loose-fitting helmets, visors, or hoods, the leak paths can vary so that not all the flow from the blower can reach the breathing zone. Some may well leak out before reaching the breathing zone.

Therefore, the PAPR needs to be designed in such a way that, it generates flow more than what the wearer can breathe plus the flow leaked over the loose-fitting interface.

How much air can be generated from the PAPR is a matter of the blowing power of the PAPR; whereas, how much air you inhale depends on how hard you need to breathe to do your job.

The reality is that the maximum flow a PAPR can generate is limited and will also be reduced from its peak when the battery level becomes lower after a certain time of use.

Also, most loose-fitting PAPRs deliver constant flow. When the flow rate is high, so will the battery capacity, making the battery larger and heavier, and this will affect wearability and cost.

On the other hand, if your job is highly physical and causes heavy breathing, your inhaled air could outrun what the blower can deliver.
The other important factor to consider is the protection factor requirement of the PAPR for doing certain work. The concentration of the contaminants and the maximum exposure limit will determine the minimum protection factor of the PAPR. Typically, loose-fitting PAPRs have a lower protection factor than tight-fitting PAPRs. When the contaminant exposure limit demands a PAPR with a high protection factor, loose-fitting PAPRs may not be suitable, regardless of whether you have a beard or not.

So to make sure a given loose-fitting PAPR is suitable for any given application, especially for a bearded person, a careful assessment is needed case-by-case.

Can Tight-fitting PAPRs be used for bearded people?

When the flow capacity of the blower, the filter used, and the system leak are equal, tight-fitting PAPRs generally have a higher protection factor than loose-fitting PAPRs.

This is because during a negative pressure condition when the inhaled air outruns the air delivered from the blower, a tight-fitting mask will let in much less outside air compared with a partially sealed loose-fitting covering.

Typically, a tight-fitting mask is made of soft silicone rubber contacting the front of the face, and it is elastic enough to adapt to the contour of the face to achieve a good seal. In contrast, a loose-fitting covering typically uses elasticized fabric at the contact interface, and it covers a much larger area, such as the head, the face, and the neck, than only the front of the face.

A tight-fitting PAPR has a much better seal over a relatively small area, whereas a loose-fitting PAPR has a partial seal over a rather large area, resulting in the leak from tight-fitting PAPAs being much less than from the loose-fitting PAPRs, hence the tight-fitting PAPRs have higher protection factor.

Now, if the beard is short enough such that the silicone cushion from the tight-fitting PAPR can still achieve a better seal than loose-fitting PAPRs, there is no reason why the tight-fitting PAPR can’t work as effectively if not better than a loose-fitting PAPR, given the loose-fitting covering has more leaks.

As an example, AYO WX PAPR, which has a well-designed silicone facial cushion, was tested on a light-beard person achieving an average PortaCount fit factor over 2000, similar to a clean-shave person under the same test conditions. The key reasons AYO WX PAPR can achieve this are due to its powerful peak flow of over 200 L/min, which is similar to most loose-fitting PAPRs, and also due to its positive pressure ensured by the responsive flow control that can quickly accelerate the blower output anytime when the inhalation increases.

So to answer the question, yes, a tight-fitting PAPR can be used with a light-beard person similarly to a loose-fitting PAPR, provided the facial cushion is well designed, the beard is reasonably short, the flow generation is powerful enough, and most importantly the ability to ensure positive pressure inside the mask.

In Summary, here are our recommendations for bearded people
 

• You must be clean-shaven when you wear a negative-pressure respirator.
• You should be clean-shaven whenever you can even if you wear a PAPR.
• If you must keep your beard, you must use a PAPR and make sure:
  • Trim your beard to a minimum for your lungs’ sake and your loved ones’ sake.
  • Perform a PortaCount fit testing to make sure the fit factor is over 1000.
  • Charge the battery in full before using the PAPR.
  • Avoid using blocked filters – change filters frequently.
  • Try not to do strenuous work to make you breathe too hard.
  • Try to use a PAPR that can produce more air.
  • Try to use a PAPR with a minimum leak path and an elastomeric mask cushion.
  • Try to use a PAPR with powerful and intelligent breath-responsive flow control like AYO WX.