Like the rest of y’all, we can’t get enough disposable N95 respirators to protect our staff. So, during COVID-19, our practice is using elastomeric respirators to protect its on-site clinicians and clinical staff.
Lest you think we’re going to try sandblasting viruses right out of infants - here’s some background information.
What’s the difference between a surgical mask and a respirator?
This article says it quite well, and with pictures, but in short: respirators form airtight seals, but masks do not. When viruses are airborne or aerosolized – or even if droplets in the air slide in through a gap - a mask will not protect as well as a respirator.
Respirators, being airtight, still have to get air from somewhere – so when you inhale, a filter catches and retains the particulate matter from their air. All respirators need to be fit-tested to make sure the user can get and maintain a good seal while speaking, turning his head, bending over, etc.
What’s a filtering facepiece respirator (FFR)?
An FFR is, essentially, a synonym for an “N95 mask” (which, as we’ve just defined, is really a “respirator”). These are what everyone wants and is having trouble finding:
These disposable respirators are made to seal tightly to the anterior face, with adjustable straps and a metal nasal band to get it to confirm. The mask material itself is the filter. Many FFRs (like this one) have an exhalation valve to get rid of heat and humidity in exhaled air.
FFRs made to be used in a surgical environment have no exhalation valve and also have a fluid-resistant coating. Since you’re probably not doing surgery in your ambulatory pediatric office, you don’t need these.
What does N95 mean?
That describes the quality of the filter. “95” means that the mask filters out 95% of airborne particulate matter, down to 0.3 microns (300 nm.) There are also N99 and N100 filters, which remove 99% and 99.97% of airborne particles, respectively.
The prefix “N” refers to “Not resistant to oil.” Similarly, the prefix “P” means “Partially resistant to oil” and “R” means “Resistant to oil.” These prefixes indicate a different axis of protection, more relevant to industrial applications than medical ones. That said, a respirator labeled “P99” is even more effective at removing airborne viral particles than an N95 mask.
So what’s an elastomeric respirator and why did you decide to use those?
Elastomeric respirators are basically reusable plastic facepieces, with changeable filters.
Here’s a elastomeric respirator without its filter-containing cartridges. This is a “half-mask” respirator, where the central piece goes over the nose and mouth.
And here’s a similar half-mask elastomeric respirator, after its two lateral cartridge filters (shaped like trapezoids) have been applied.
There are also full-face elastomeric respirators, in which the entire face is covered. This one has the lateral filter cartridges:
This doesn’t sound as good as the traditional health care FFR.
For convenience and ease of use, the traditional healthcare respirator is lighter, disposable, and causes less voice distortion when you speak through it.
But elastomeric respirators offer:
- equal, and even better filtration than FFRs (P100 filters permit only 0.6% of the particulates that pass through N95s).
- much more durability than paper N95s, which must be discarded when soiled or torn
- long-lasting service - if the filters are changed periodically, they can be reused for months to years.
A NIOSH fellow wrote about the “overlooked elastomeric respirator” on a CDC blog:
This makes the device valuable during times of high demand, such as during a pandemic. Unfortunately procedures for disinfection and decontamination within healthcare environments are not routine and must be established for the environment where elastomerics may be used. Further complicating its common use, many healthcare workers have never heard of the elastomeric respirator, which indicates that there is a great need for education about the option of this type of respiratory protection.
Where can I get elastomeric respirators?
Right now, purchasing anything pandemic-related is in flux. But your local hardware store or paint supply store may have elastomeric facepieces, cartridges, and filters. It’s even better if they have all-in-one kits.
What should I buy?
First, medium-sized elastomeres appear to fit most adults. We bought 15 medium-size 3M half-masks (6000 series) for our clinicians and in-house clinical staff. We had successful fit testing on 2 men and 12 women using the medium mask. One woman with a small face could not get a good seal during fit testing and needed a small mask. A larger man with a wide face might need a large-size face mask.
Look for reusable, not disposable, elastomeric respirators. A disposable elastomeric comes with a single set of filters that are not detachable and cannot be replaced; when the filters are saturated (i.e. it becomes difficult to breathe), the whole apparatus is meant to be discarded.
Common brands include 3M & Honeywell; less common brands include Moldex and SAS.
If possible, purchase all your masks using the same brand because each brand has a different shape of filter/filter retainer. For example, 3M uses a trapezoidal-shaped filter; SAS and Honeywell use round-shaped filters. Also, different brands use different locking mechanisms between the filter retainer/cartridge and the mask. They are not interchangeable between brands. Purchasing one brand of mask means you only have to purchase one type of filter and one type of cartridge/filter retainer.
When purchasing filters, be sure you are purchasing particulate filters (N95, P100, etc), and not solely gas filters (“organic,” “acid,” etc). A combination or double-layer filter (“P100 organic vapor”) is OK.