Among a variety of things, to use an Air Purifying Respirator, you must:
- To properly wear a respirator with a tight fitting seal, you must be Fit Tested, and you need to be clean shaven during Testing or during use, 1 Day’s Growth is usually OK.
- Have the Correct Filtering Element; i.e. Cartridge, Filter, a Combination of Both, or the Correct Paper or Disposable Mask; for the Exposure
- Be sure that the Level of the Contaminants you’ll be exposed to are within range for the Type of Respirator that you intend to use.
- Be aware that for Unknown Exposures, or Exposures that are classified as Immediately Dangerous to Life and Health, that Air Purifying Respirators, Including Powered Air Purifying Respirators, are not permitted.
- Air Purifying Respirators DO NOT SUPPLY OXYGEN. The Oxygen in the area where they are to be worn must be 19.5% Minimum, Air is normally 21% Oxygen. Air Purifying Respirators in any form are not for use in areas with lower than 19.5% Oxygen.
Assigned Protection Factors (APF):
Disposable Filtering Facepiece Respirators Assigned Protection Factor was 5, until OSHA raised it to 10 for Disposable Filtering Facepiece Respirators because the manufacturers told them to list it at 10. I’m not seeing their reasoning, I don’t agree, other organizations have recommended 5 as well. You’ll see the significance of the APF shortly.
1/2 Face (Elastomeric Respirators) Air Purifying Respirator APF is 10
Full Face Air Purifying Respirator APF is 50.
1/2 Face, Powered Air Purifying Respirator APF is 50.
Full Face Powered Air Purifying Respirator, (see the Image Above) APF is 1000.
Assigned Protection Factors help to determine the concentration of a substance that the Respirator can be used for if the Respirator Cartridge or Filter is appropriate, and providing you follow other requirements of Respirator Use.
Let’s use Benzene as an example. Benzene is an “Organic Vapor” and has a Permissible Exposure Limit of “1 ppm (part per million) averaged over an 8-hour workshift and 5 ppm, not to be exceeded during any 15-minute work period (and I think that’s a one time thing in 24 hour period).
So, I can be exposed, in the workplace, up to 1 ppm Benzene without a respirator.
If I’m wearing a Half-Face Respirator with an Assigned Protection Factor of 10 (that’s all the higher it goes for that style), I can be exposed to 10 ppm of Benzene because the respirator will reduce it by a factor of 10.
If I’m wearing a Full-Face Respirator with an Assigned Protection Factor of 50 (that’s all the higher it goes for that style), I can be exposed to 50 ppm of Benzene because the respirator will reduce it by a factor of 50.
All Negative Pressure Respirators leak as you breathe in. Some much more than others. Powered Air Purifying Respirators pressurize the respirators, so filtered air leaks out of the mask if the seal is less than perfect, preventing contaminants from entering.
Respirators may create a false feeling of safety around diseases, since trying to avoid breathing airborne droplets will be negated by touching contaminants and then your mouth, nose, or eyes. The tears in your eyes drain into your sinuses, so exposure to your eyes from droplets from a cough or sneeze may infect via your sinuses.
Here’s interesting and relevant links:
And Downloads from the Navy on Respirators:
Industrial Hygiene Field Operations Manual – Technical Manual NMCPHC-TM6290.91-2 22 NOV 2019 – Chapter 9 – Respiratory Protection
Respiratory Protection for Airborne Exposures to Biohazards – a PDF Download Points out many things, also that Surgical Masks are to prevent the Germs the Doctor has from Infecting the patient.
The Link Immediately Above is in Archive Form and not Updated, a Useful Reference. It discusses some reasons why properly used Disposable Filtering Facepiece Respirators are effective, yet says you must be careful not to touch the front of the contaminated Respirator.
To Stop Droplets, aerosolized droplets, and Particulates, I’d want the best protection reasonably affordable. In the above 2 links, they discuss P-100 and N-95 Filters.
P = Oil Proof (No degradation of the filtering element when exposed to aerosolized oils). P-100 is Oil Proof and removes 100% of the applicable Contaminants (99.97%)
N Means Not Oil Proof. Filter media will degrade with aerosolized Oils. N-95 is Not Oil Proof and removes 95% of the Contaminants.
R Means Resistant to Oil. The filter media can accept a certain level of aerosolized oils without degrading, but only for a single shift or 8 hours of continuous or intermittent use, or otherwise according to the manufacturer’s instructions. In the absence of aerosolized Oils, the Respirator or Filtering Element can continue to be used in a similar fashion to the N-Series.
Ultimately, Disposable Filtering Facepiece Respirators will be Better at preventing the Spread of Sneeze and Cough Generated Particles from an infected person wearing a Paper Mask Filter than stopping the spread of an infection to an uninfected person Wearing a Disposable Filtering Facepiece Respirator if the infected person isn’t.
Here’s some reasons why.
All Negative Pressure Respirators create a lower pressure area inside the Respirator Facepiece than the pressure outside, and this occurs with Inhalation (Breathing in) and the Resistance to the Flow of the Air Across the Filtering Element. During this time, particles from outside the Facepiece can move into the Facepiece through areas of poorer Facepiece to Facial Seal of the Respirator.
For Qualitative and Quantitative Fit Testing, the user must be clean shaven in the area when the respirator contacts the face and for a slight margin beyond that. One Days Beard Growth is usually acceptable
At work, we had Yearly Tests for Respirator Fit. The first few years, they used Smoke, the respirator Model and Size you’d use was fitted with Particulate Filters, and a very irritating smoke was applied around the respirator, if there was a substantial leak, the person being tested would cough. This is known as Qualitative Fit Testing.
Although following is an ad, I have noting to do with the company, I’ve never heard of them before, I genuinely suspect that no one here will be buying the equipment. It conveniently shows what we had done every year, on every Respirator Style we might be wearing. The Electronic Device Does Quantitative Fit Testing, it actually measured the leakage.
Let’s step aside for a moment. It’s related. At work, we wore Headlamps. Fascinating things, Headlamps, they look the way you look, so you can be in a dark room but see clearly wherever you walk. But, they are on your head, or hard hat, and therefore close to your eyes. It was then I noticed how Fog is actually tiny particles, and not some uniform saturation of moisture. Teeny, Tiny, Particles, floating in the air.
Ok, back to Respirators. When doing the Quantitative Fit Testing mentioned above, they were having problems getting the Test Completed, requiring some people to be retested and taking more time. They Discovered that the Addition of an Ultrasonic Humidifier took care of that problem, generating tiny particles circulating in the room.
The Quantitative Fit Test Device compares the number of Particles Outside the Facepiece with the number of Particles Inside the Facepiece, by sampling the Air in both locations. On a two filter Respirator, one Filter is a P-100 to stop Particles, the other one is fitted with an adapter to hold and seal the Instrument Probe.
As the Test Progresses, the computer prompts you to:
- Normal breathing
- Deep breathing
- Turning head side to side
- Moving head up and down
- Bending over
- Normal breathing
All the while, a progress bar for each stage of the test is shown, preferably in Green, sometimes changing Yellow, and Occasionally Red. This represents Particles Infiltrating into the Tight Fitting Facepiece as you breath, move, make facial expressions, and talk.
Invisible Particles of Moisture from the Ultrasonic Humidifier are entering the Facepiece and would therefore be breathed in; as would Particles of Moisture from a cough or sneeze, and if they are laden with a virus; would pose a transmission problem to people even wearing Tight Fitting Respirators, it must be so, the invisible Ultrasonic Particles are getting in.
Additionally, with Airborne Disease Pathogens, even if you can perfectly seal a Half Face Respirator to your face, the particles landing in your eyes will drain into your sinuses with the Lacrimal Fluid (Tears) around your eyes.
Disposable Filtering Facepiece Respirators cannot possibly seal to the level of Half Face Tight Fitting Facepieces. Yet the Half Face Tight Fitting Facepieces, demonstrably, are leaking too, just far less.
HAZMAT Responses often use Fully Encapsulated Suits, with the Self Contained Breathing Apparatus (SCBA) in the suit with the user. The SCBA provides Breathing Air to the user, but when the user exhales, the Air Stays in the Suit, and the Suit gradually grows larger and larger, requiring Burping the Suit to Purge the Air.
But a key point of these suits is that they Stage in Areas of Decontamination. Whatever is on the suit can aggressively be washed off since exposing the outside of the suit to the harsh chemicals perhaps needed to neutralize a pathogen, or to purge off a chemical, can be done without exposing the wearer.
After we get home from wearing Disposable Filtering Facepiece Respirators, possibly with the leakage around the mask significant, and leaving the eyes exposed, we then throw away the mask, handle our phone that was with us, untie our contaminated shoes, take off contaminated clothing, and rub our eyes, mouth, or nose, possibly then becoming infected.
Disposable Filtering Facepiece Respirators Are better at Containing Sneezes and Coughs of Infected Persons than they are at preventing exposure to a pathogen from someone wearing a mask. It might create a false sense of security and lead to infection via slightly indirect methods.
Yes, I’d wear a Disposable Filtering Facepiece Respirator, since the interception of the pathogen would indeed stop the infection from occurring, but if the particle circumvents the seal of the Mask, lands in your eye, or is transferred by your hand to your mouth, nose, or eyes, from your shoes, phone, purse, etc., later, you may, and likely will, become infected.
1 and 4, Disposable Filtering Facepiece Respirators, they don’t seal extremely well.
2, 3, 5, and 6 are Half Face Air Purifying Respirators
- 2 Has a P-100 Particulate Filter and Chemical Cartridge
- 3 Has a Chemical Cartridge without the Particulate Filter.
- 5 Has a P-100 Particulate Filters without Chemical protection
- 6 Has Chemical Cartridge without Particulate Protection.
7, 8, 9, 10 are Full Face Air Purifying Respirators
- 7 Has a P-100 Particulate Filter and Chemical Cartridge
- 8 Has Chemical Cartridge without Particulate Protection
- 9 Has a P-100 Particulate Filter and Chemical Cartridge
- 10 Has Chemical Cartridge without Particulate Protection
Chemical Cartridges alone aren’t approved for Particulate Protection, but with an Integral Filter, even if the Chemical Cartridge has no efficacy on the Particulate Contaminant, the Particulate Filter will provide protection.
See the Following Link, Color Codes, Cartridge and Filter Forms, and More: