TOTOBOBO mask in NIOSH site

Totobobo mask was spotted in NIOSH NO-FIT-TEST workshop page    Totobobo mask was spotted in NIOSH NO-FIT-TEST workshop page

I was surpriced when my friend show me this page in CDC site. NIOSH, the National Institute of Occupational Safety and Health under CDC, is the US organization who certify the well known N95 mask. What made TOTOBOBO, a little known Singapore invention of respirator mask, appears in this heavy weight website?

No, TOTOBOBO is not certified by NIOSH, at least not yet. The picture of an early version of TOTOBOBO mask found in the NIOSH website is to serve as an inspirational example for a “No Fit Test” filtering facepiece respirator workshop. The workshop will be conducted in Nov. 6 later this year and the objective is:

“To better understand the interdisciplinary research needs and challenges in developing and certifying a universal “no-fit-test” filtering-facepiece respirator”

I think this is totally appropriate and it shows NIOSH recgonize the need to improve the current procedure in order to motivate manufacturers to innovate toward the direction of “No fit test” respirator. 

Why is this big fuss about “No fit Test”?

If you read carefully the fine text of your respirator instruction, you will notice a statement similar to this:

“Before use of this respirator, a written respiratory protection program must be implemented meeting all the requirements of OSHA 29 CFR 1910,134 such as training, fit testing, medical evaluation, and applicable OSHA substance specific standards.” 

The simple fact is, the rated protection value will be drastically reduced if the mask does not fit your face, and there is no other ways to tell except by doing a fit-test. Buying a mask is easy, but getting a mask fit-tested on each individual is a challenge. In emergency situation like flu pandemic or haze outbreak, it is simply not possible to get everyone a fit tested at once. 

One can start to sense the “pain of fit test” and how touchy this issue is from the following comment in one of the NIOSH science blog :

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NIOSH debate how often to fit test

NIOSH debate how often to fit tes

Hopeful to see Fit-Test to be lifted– Edward Hernandez, City of Hialeah, Fire Rescue says:- Thank you for proposing a study as this. For a while now this OSHA (Fit-test) requirement  has been a burden to our Fire/EMS service.

Hopeful to see Fit Test to be simplified-Peggie Reinhardt, RN BSN, says:

I would be interested in this study, we currently fit test our employees annually. If this process could be shortened or redesigned so that it was easier to do would help tremendously.

Fighting to keep Fit-Test in organization– Sgt. Julie Love says:

I would be interested in being part of this study on the law enforcement side. We fit test our officers annually but many departments do not. Law Enforcment traditionally has fallen down in this area as many agencies just give their officers their masks without any fit testing. We also fight the battle with our management with what is mandated.

Worry that No-Fit-Test= Not Safe-Kevin MacDonald says:

 I am concerned that changing the fit test frequency while cost effective may defeat its overall purpose. when fit testing went from every 6 months to one year as a requirement of OSHA it was a step back.

Confused and concern-Kelly Russell says:

I am glad this study is being done. Respiratory fit testing is expensive for employers and it will be good to have a current answer when asked why we have to do the testing so often….or maybe not so often as the case may be.

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No matter what, the setting up of this workshop itself is already a breakthrough, and we are definitively happy to be associate with the solution side of the problem. We hope the result of the workshop will bring more practical innovation into the design and certification of respirator, especially taking people like housewife and children who don’t have access to fit-test equipment but also deserved to have good protection when situation come.

Does smaller particle always penetrate filters easier?

Common sense would suggest smaller particle always penetrate filter easier. But this is not always, as state in the FAQ of CDC site:

1. How effective are the Part 84 filter respirators against particles smaller than 0.3 micrometer in diameter?

The 0.3-micrometer diameter used in the certification testing is approximately the most penetrating particle size for particulate filters. Although it seems contrary to expectation, smaller particles do not penetrate as readily as 0.3-micrometer particles. Therefore, these respirators will filter all other particle sizes at least as well as the certified efficiency level.

2. How effective are the Part 84 filter respirators against asbestos fibers or other rod-shaped particles?

Although fibers or rod-shaped particles may have very small cross-sectional diameters relative to their lengths, the Part 84 particulate filter respirators will be at least as efficient against this particle shape as the certified efficiency level.

CDC is right, this is contrary to expectation. The reasons is explained in another document in more details. Here is a diagram from pg. 9 of the document showing there are actually four different collection mechanisms govern particulate air filter performance: inertial impaction, interception, diffusion, and electrostatic attraction:

4 different collection mechanisms of particulate filters

The first three of these mechanisms apply mainly to mechanical filters and are influenced by particle size.

  • Impaction occurs when a particle traveling in the air stream and passing around a fiber, deviates from the air stream (due to particle inertia) and collides with a fiber.
  • Interception occurs when a large particle, because of its size, collides with a fiber in the filter that the air stream is passing through.
  • Diffusion occurs when the random (Brownian) motion of a particle causes that particle to contact a fiber.
  • Electrostatic attraction, the fourth mechanism, plays a very minor role in mechanical filtration. After fiber contact is made, smaller particles are retained on the fibers by a weak electrostatic force.

Impaction and interception are the dominant collection mechanisms for particles greater than 0.2 ?m, and diffusion is dominant for particles less than 0.2 ?m. The combined effect of these three collection mechanisms results in the classic collection efficiency curve, shown in the following Figure:

Fractional collection efficiency versus particle

The TOTOBOBO filters is a type of electrostatic filters which contain electrostatically enhanced fibers. Such fibers actually attract the particles to the fibers, in addition to retaining them. Electrostatic filters rely on charged fibers to dramatically increase collection efficiency for a given pressure drop across the filter.

Following table gives a rough idea of how small a micron is:

 Substance  Micro-meters (microns)  Inch
 90% of Wood smoke particles are smaller than   1 micron  0.00004
 Bacteria (average)   2  0.00008
 Red Blood Cell   8  0.0003
 Talcum Powder   10  0.0004
 White Blood Cell  25  0.001
 Human Hair   70  0.003
 Grain of Table Salt  100  0.004

Read more:

Used filters from India

Clearly a Better Way to Check for Safety

The protective function of a respirator mask is based on two functions;
(1) the filter media must let in air but stop harmful and unwanted particles from entering the breathing zone.
(2) the mask must fit the user’s face and form a complete seal so that no air bypasses the filter media and enters the breathing zone directly.

Filter + Face seal = good protection

principle of respiratory mask protection

Modern technology has produced highly efficient filter media that can achieve up to an incredible 99.9% filtration efficiency. Ensuring a secure mask-to-face fit, however, is not nearly as simple. Rarely do users achieve a professional-grade fit, and they are surprised when they do.

Fit-testing is a task that requires a trained professional, special equipment, knowledge and skills, and considerable time. There is QUALITATIVE fit test based on subjective senses of the user, and there is QUANTITATIVE fit test based on objective measurement which compares the particle counts inside and outside of a mask. The National Institute of Occupational Safety and Health (NIOSH) recommends that such a fit-test be conducted yearly for each user so as to ensure proper usage. Fit testing can determine if a mask fits the user during the test, but can not tell for sure if the mask still fits the user days or months afterwards. These fit-testing procedures are limited to occupational users and not commonly available. The general public has neither the equipment, nor training, nor expertise, nor regular access to professionals who do in order to conduct professional-grade testing on their protective respiratory masks when they need it.

In a recent study “Respiratory Donning in Post-Hurricane New Orleans” (published on the US CDCwebsite in May 2007), researchers found 76% participants were not able to demonstrate proper donning, resulting in the compromising of their protection. This study group should know a thing or two about proper protective mask use considering the ordeal they went through during the post-Katrina clean-up of New Orleans. Imagine in an emergency situation, what would happen if the public needed to wear respirators to protect themselves? How many of these people will be able to fit their mask properly? Less than 24%, perhaps? CDC has been reluctant to recommend N95 masks for the public use because for 3 out of 4 people the poorly fitted respirator may provide a fault sense of security and encourage risky behavior.
The Prince of Wales Hospital of Hong Kong conducted a study where subjects who had previously passed a fit test were asked to properly don a N95 mask and then check for adequate sealing. These same subjects were then given a TOTOBOBO mask which they have not previous experience and conducted the same test. The results found that although the TOTOBOBO mask performed slightly less than the N95 mask, most test subjects did achieve the appropriate fit and pass the test. How did the non-fit tested Totobobo match the fit-tested N95 mask for this group of users?

Transparent surface indicates good face seal of Totobobo mask

Transparent surface indicates good face seal of Totobobo mask

The TOTOBOBO mask solves the uncertainty about proper fit in a simple but extremely effective way. The transparent mask makes fit checking an easy task. Check around the perimeter of the mask and you can immediately decide if the face seal is good or not. This simplicity, combined with a soft material that comfortably fits your face, makes fitting a lot more intuitive and reliable. Now you can perform a more reliable face-fit check every time before entering a contaminated area. This is certainly more reassuring than relying on once a year fit test.

Reference:
ESICM Annual Congress-Totobobo-mask-1044