CATER Mask Decisions

December 11, 2020

Consumer Mask Decisions

CATER Mask Decisions

December 11, 2020


Here is the Largest Emergency Room

SGS Provides Guide to Public Mask Regulations

CATER Mask Requirements

Qualitative Fit Testing for Every Facility

French Barrier Mask Requirements were Established in April

NC State Working on Procedures for Cloth Mask Testing

Washington Post Funds Infra-Red Camera Analysis of Virus Exhalation


Here is the Largest Emergency Room

The grim news is that there are millions of people on this planet capable of transmitting COVID at this moment. Even though these people are dispersed around the globe the risks of infection are as high as you would normally experience in a hospital emergency room. Companies such as Mann +Hummel and Daikin-AAF are viewing the world as one large cleanroom where ambient air flow and cleanliness need to be managed.

CATER masks are an important product in a successful battle. If you suggested to a semiconductor cleanroom operator that a 30% efficient mask would be better than nothing his reply would be maybe so, but you are not going to enter his cleanroom. If the most efficient masks are needed to reduce chip losses what about the value of human losses?

Biopharmaceuticals are produced in cleanrooms where the ambient particulate levels of 500,000 particles/ft3  0.3 microns and larger are reduced to just 10 particles. With the advent of closed  systems the worker is no longer in the space but nevertheless room cleanliness is kept at 10,000/ft3.

When most of the world’s population is vaccinated it will be the equivalent of closed operations in a biopharmaceutical  facility. But there will be other viruses, air pollutants, allergens, wildfires, and air contaminants. Therefore a relatively high level of HVAC filtration and use of efficient masks will continue for the foreseeable future.

SGS Provides Guide to Public Mask Regulations

As more individuals turn to reusable face masks, most often ‘do-it-yourself’ (DIY) made from fabric, countries have begun to develop regulations, standards, and guidelines to ensure their proficiency.

As a fabric mask is directly in contact with skin for potentially long periods of time, relevant restricted substance and biocompatibility testing are highly encouraged. Also, the ear loops have to be securely attached to a reusable mask for the duration of its expected lifetime.

Relevant performance testing for fabric face masks include:

  • Barrier performance
  • Breathing resistance
  • Functional testing
  • Colorfastness testing
  • Ear loop attachment strength
  • Restricted substances

SGS earlier this year prepared listing of the specifications in various countries. It will need to be updated but is a good starting point.

Of all the specifications, ‘barrier performance’ is the most crucial when it comes to reusable fabric masks. Most locations have adopted particulate filtration efficiency (PFE) as the major barrier performance, while bacterial filtration efficiency (BFE) is specified in Spain and Portugal.

Summarized below are the barrier performance regulations/standards/guidelines in some markets:









French Cross Ministries Note (NOTE d’INFORMATION du 29 mars 2020 Mise a jour le 26 avril) Mandatory requirement in France


Dissolved gas analysis (DGA) method Annex 2 or equivalent

Particles size: 3 microns:
> 90% for UNS Class I
> 70% for UNS Class II


AFNOR Spec S76-001 v1.1


DGA method Annex 2 or equivalent

3 microns particles:
> 90% for UNS Class I
> 70% for UNS Class II


National standard

UNE 0065


EN 14683:2019 + AC: 2019 Clause B

≥ 90%


National Standard

NBN/DTD S 65-001:2020


EN 13274-7:2019

≥ 70%


EN 14683:2019+AC:2019 Annex B

≥ 70%


National standard

SWiFT 19:2020


EN 14683:2019+AC:2019 Annex B

≥ 70%


Portugal specifications

Masks intended for use under COVID-19 technical specifications 1


EN 13274-7:2019

Level 2: ≥ 90%
Level 3: ≥ 70%


EN 14683:2019+AC:2019 Annex B

Level 2: ≥ 90%
Level 3: ≥ 70%


Recommendation by task force

Swiss National COVID-19 Science Task Force


Particle size: 1μm

≥ 70%



BfArM recommendations



Attention on marking and labeling issue

United Kingdom


BSI guide to masks and face coverings for use in the UK during the COVID-19 pandemic


EN 13274-7:2019

Requirement to be determined by the Cabinet Office/Department for Business, Energy and Industrial Strategy (BEIS)

EU countries

Reference document from the CEN Members

CEN Workshop Agreement
CWA 17553


EN 13274-7:2019

Particles size: 3 microns

Level 90%: min 90%

Level 70%: min 70%

United States

Recommendation by industry

General Purpose Woven Face Coverings – Guidance and Considerations

*Not Applicable

ASTM F2299 or technical equivalent, with modified micron size

3 micron particles >= 70% filtration efficiency as minimal


Association standard

T/CSTM 00387-2020


GB/T 38413-2019

PM 2.5 daily reusable protective mask
As received: ≥ 95%
After care: ≥ 90%

General daily reusable protective mask:
As received: ≥ 90%
After care: ≥ 85%

South Africa


Recommended Guidelines


EN 13274-7:2019

Particle size: 5 microns

≥ 75%

SGS offers testing and consultation services for interested parties on fabric masks to test if the product performance satisfies relevant regional specifications and requirements, and shares information on export/import procedures.

The network is capable of providing mask testing and consultation services in the following locations:

  • Hong Kong, China
  • Shanghai, China
  • Cestas, France
  • Appleton, USA
  • Fairfield, USA
  • Grasslake, USA


CATER Mask Requirements

Here are some of the parameters which are needed to create a good CATER mask


Suitable constituent materials safe for respirators (including textiles, filter media, inks and dyes, packaging) 

Designed to facilitate correct positioning on the user and remain in place

Adequate adjustment options, such as no charge wrong size replacement, head strap accessory and noseband 

No restriction of the user's field of vision

Easy breathing established by inhalation and exhalation resistance tests


Aesthetics of product appearance on face 

Designs and colors 

Encourages compliance in mask wearing

Encourages mask use in all environments


Manufacturer to supply correct donning, doffing, fitting, and noseband instructions

Product support to ensure correct size 

Practical performance testing on test subjects to determine leakage under normal activities


​3rd Party Testing on all design and engineering changes

NaCl Particle Filtering Efficiency at mean diameter .3-microns

Continuous flow rate at 85 L/min 

Quality plan in manufacturing to include Quality Checkpoints and Inbound Quality Inspection

Clear communications for consumer on reason for various particle size testing 

Minimizes reduction in speech communication


Components designed to maximize number of wearings

Clear instructions on cleaning and care which minimize efficiency reduction

Qualitative Fit Testing for Every Facility

Every meat processor, industrial plant, corporate office building, restaurant, and other entity in need of tight fitting masks should provide CATER masks for their employees and assure that the right size mask is available for each employee and that they are wearing them properly. Since leakage is just as important as mask media efficiency we recommend that a firm such as Examinetics come to each facility and conduct qualitative fit tests on each employee after they have received the right tight fitting mask.



Qualitative fit testing is a pass/fail method used on half-masks that relies on senses - such as taste and smell - to detect air leakage from the respirator. The half masks being tested must have an overall fit factor (mask particle concentration divided by the ambient particle concentration) of 100 or less. The test relies on a harmless, yet bitter-tasting chemical called Bitrex, which will determine whether you pass. Rather than measuring the amount of leakage into the facepiece, the qualitative fit test determines whether the facepiece is in working order. Unfortunately, if you taste a bitter substance, it is a fail.

For those who cannot detect bitter taste, they offer saccharin, an artificial sweetener, as a replacement. 

  • Bitrex: a chemical that leaves a bitter taste in your mouth
  • Saccharin: a chemical that leaves a sweet taste in your mouth

There may need to be some adaptation for masks such as used in non-medical facilities. For example, the amount of chemicals could be diluted so that the pass fail test approximates what would be achieved in a mask with a 80% net efficiency.

Examinetics has a fleet of more than 130 mobile units that come to the facility. The fleet provides flexible scheduling options and a centralized solution for occupational health needs.

The activity could be coordinated with mask suppliers or with larger mask retailers. Walmart could offer a program where you buy the mask and are tested in their parking lots.

French Barrier Mask Requirements were Established in April

Yesterday we reported on the new update to the French standards to take into account masks with a clear area around the mouth.  Here is a good summary by SGS of the basic standards which were published in April.

The French association, AFNOR, has released AFNOR SPEC S76-001 “Masques barrières" or “Barrier Masks” (in English), a standard that establishes minimum requirements for non-medical general purpose masks.

The French standards association, AFNOR, has released AFNOR SPEC S76-001 “Masques barrières" or “Barrier Masks” (in English), a guideline that establishes minimum requirements for general purpose (non-medical) woven masks.

AFNOR Group designs and deploys solutions based on voluntary standards around the world. The Group serves the general interest in its standardization activities and provides services in such competitive sectors as training, professional and technical information and intelligence, assessment, and certification.

AFNOR sponsored a group of industry experts along with members of standardization commissions for personal protective equipment (PPE) and for textiles. The guideline provides the minimum requirements, methods of testing, fabrication and use of general-purpose woven barrier masks.

Per the guideline, a woven “barrier mask” is intended for use by healthy people not exhibiting clinical symptoms of viral infection and not being in contact with people with such symptoms. Such masks do not provide the same medical benefits or protection than those for which EN 14683 (medical masks) or EN 149 (respiratory protective devices) are applicable.

AFNOR SPEC S76-001 masks are not medical devices, and thus are not within the scope of Medical Device Directive 93/42/EEC or Medical Device Regulation (EU) 2017/745. Neither are they PPE, and thus do not fall under the scope of Regulation (EU) 2016/425. 

In an industry landscape typically dominated by medical and protective masks/respirator performance standards, SPEC S76-001 becomes one of the few standards that addresses general purposes woven masks. Viewed as critical to address mask shortages; woven masks allow for reusability while their construction leverages the much larger textile industry instead relying solely on nonwovens. Furthermore, this allows medical masks to be prioritized to healthcare workers and patients.

As COVID-19 continues to develop, Governments have been increasingly recommending citizens to wear masks in public, protecting both themselves and workers providing essential services to the public. This has led to a sharp increase in the demand for general purposes masks. Manufacturers seeking to meet this demand can now look to SPEC S76-001 to ensure their masks meet an acceptable level of performance and safety.

AFNOR SPEC S76-001 requirements include, but not limited to:

  • Visual Inspection and Dimensions
  • Packaging and Materials
  • Marking and Labelling
  • Cleaning and Drying
  • Breathing Resistance (Breathability), and
  • Penetration Resistance (Particulate Filtration)

A critical component to the guideline is washing and drying, as the manufacturer must decide:

  • Mask washing instructions
  • Duration of use before mask should be washed (4 hours maximum)
  • The maximum number of washes before mask should be disposed

To validate efficacy, the penetration and breathability tests are to be performed after the maximum number of washes. Product must meet minimum specified penetration and breathability requirements. The penetration of the barrier mask shall have either a filtering capacity of 70% for solid particles or for liquid particles (droplets) with a particle size spectrum extending up to 3 μm.

On 29 of March 2020 French Government issued a cross ministry (Labour, Health, Finance) instruction defining two categories of masks “Usage Non Sanitaire” (Non-medical purpose): UNS 1 and UNS 2.

  • Cat I – UNS 1: for workers who have frequent and regular contact with the public such as policemen or cashiers
  • Cat II – UNS 2: for people in a group wearing the same kind of masks (in a company, in a service, in a warehouse…), and who are occasionally in contact with public.

Using methodology referenced in AFNOR SPEC S76-001, UNS 1 Masks must perform at a 90% filtration level while UNS 2 masks must reach 70%. The cross ministry note, also specifies breathing resistance requirements, marking, minimum number of washes, like AFNOR SPEC S76-001.

SGS has gathered multiple experts to study the AFNOR guideline and the French Government’s cross ministry instruction to prepare testing and inspection protocols. Combining their experts from their various laboratories (Filtration, medical devices, medical supplies, personal protective equipment, and textile experts) they offer a unique multi-faced solution. Allowing clients to verify their compliance to AFNOR SPEC S76-001 and Ministry instruction, through testing of the prototype, inspection of the production lots, with possibility of additional critical tests from the production lot.

NC State Working on Procedures for Cloth Mask Testing

Researchers at the North Carolina State University Textile Protection and Comfort Center are working on consistent and reliable ways to test the effectiveness of cloth face masks used by the public to limit the spread of the coronavirus, building on their expertise in testing protective equipment for firefighters and first responders.

“In March, we saw that people were making cloth masks, and we realized there were no specifications or consistent testing for them,” said Bryan Ormond, assistant professor of textile engineering and chemistry in the NC State Wilson College of Textiles. “We started looking at: How do we look at making better tests?”

The Center for Disease Control and Prevention recommends the general public wear multi-layer cloth masks to prevent transmission of SARS-CoV-2, the virus that causes COVID-19, by reducing spread of the virus through respiratory droplets as well as to reduce inhalation of droplets by the wearer.

To learn about strides in testing cloth face masks, the Abstract (the NC State newspaper)  sat down with Ormond to talk about research into testing cloth masks for the public, which are considered the last line of defense against the spread of the coronavirus.

The Abstract: Can you describe some of the tests you’re doing on face masks worn by the general public?

Ormond: We worked during the pandemic at our homes, some in the lab, to put together a couple tests to be able to just get a screening level using ambient air particles. We wanted to see how well the materials filter.

We essentially put fabric in a cell, passed air through it and counted the particles on either side. That gives us an idea of the filtration efficiency. We recently added an aerosol generator to give us a consistent level of particles at a consistent size because you can’t really control ambient air from day to day.

The other approach is to look at the full product. When you make a cloth face covering, it is not a flat piece of material. It has the openings around the face, the nose. It has a fit factor that also affects the performance.

We have an animatronic breathing head form that we can control. Testing masks on our articulated head form allows us to simultaneously get a measure of filtration efficiency and fit.

TA: How do cloth face masks protect people?

Ormond: Any time you’re dealing with some sort of hazard you’re trying to protect people from, you look at this hierarchy of strategies for how you can control the hazard. Typically, you’re starting with administrative and engineering controls. In this case, that refers to keeping 6 feet of distance, washing your hands and staying at home – those are going to separate you from the hazard.

The PPE, the respirators and the face coverings are a last line of defense in any situation, not just in respiratory protection.

The other is this idea of getting everyone to realize that a mask, a face covering is just one of the tools that we can use. It’s a public health strategy. Every single person wearing a mask just cuts things down a little bit from spreading.

TA: Are there standards for cloth face masks?

Ormond: Right now there is no certification process or specification for cloth face coverings for the general public. The American Association of Textile Chemists and Colorists, AATCC, came out with a design specification or guideline on how to construct them.

Now, a task group of ASTM International’s subcommittee on respiratory protection – with experts from around the country – is coming together to put together a specification. That involves setting design and performance requirements so every mask can be certified through a process. We also have to pick the correct test methods that provide relevant performance to the use conditions

TA: What do you look for in a face mask?

Ormond: There are three main performance characteristics you want to look at. One of those is filtration efficiency. If you pass air with particles through that fabric, how many particles does that fabric actually stop?

The next thing that you want to look at is breathability. Filtration and breathability typically have an inverse relationship, so as you increase the filtration performance, the material or composite becomes less breathable. So the balance between these two is critical for an effective face covering.

The last one that’s most important for providing any protection to the wearer is the fit. If the mask doesn’t fit and seal to the face, you can have the best filtration material possible, it can block everything in a material level test, but if you put it on your face, what’s going to happen is the air you’re breathing in is actually going to follow what we call a “path of least resistance” and move around the material instead of through it. This is less of a concern if you are intending the face covering to only function as a means to limit spread and protect others from the wearer.

TA: What’s your ultimate goal for face mask testing?

Ormond: We want to be able to develop a rating system. Right now a regular person shopping for a mask is looking at four, five different masks, and has no real way of comparing those. If you have a specification in place, you at least know that these have been through a process, that they have been tested, shown to work to some level that has been agreed upon by a group of experts.

The other thing you could do is you can show how one varies in breathability or material filtration. What you want to have is to get a measurement or a rating of how breathable something is so people can make an informed decision.

Washington Post Funds Infra-Red Camera Analysis of Virus Exhalation

Recent infra-red tests funded by the Washington Post show that  the virus travels long distances. But since many of the droplets are too small to be picked up by the camera the situation is even worse than shown.

As winter approaches, the United States is grappling with a jaw-dropping surge in the number of novel coronavirus infections. More than 288,000 Americans have been killed by a virus that public health officials now say can be spread through airborne transmission.

The virus spreads most commonly through close contact, scientists say. But under certain conditions, people farther than six feet apart can become infected by exposure to tiny droplets and particles exhaled by an infected person, the Centers for Disease Control and Prevention said in October. Those droplets and particles can linger in the air for minutes to hours.

To visually illustrate the risk of airborne transmission in real time, The Washington Post used a military-grade infrared camera capable of detecting exhaled breath. Numerous experts — epidemiologists, virologists, and engineers — supported the notion of using exhalation as a conservative proxy to show potential transmission risk in various settings.

“The images are very, very telling,” said Rajat Mittal, a professor of mechanical engineering in Johns Hopkins University’s medical and engineering schools and an expert on virus transmission. “Getting two people and actually visualizing what’s happening between them, that’s very invaluable.”

The highly sensitive camera system detects variations in infrared radiation that are not visible to the naked eye. The technology is more typically used in military and industrial settings, such as detecting methane gas leaks in pipelines. In 2013, it was deployed by law enforcement during the 20-hour manhunt for the Boston Marathon bombers.

But fitted with a filter that specifically targets the infrared signature of carbon dioxide, the camera can be used to map in real time the partial path of the nearly invisible particles we exhale.

According to experts, the footage underrepresents the potential risk of exposure from airborne particles. Those particles may spread farther or linger longer than the visible exhalation plume, which dissipates quickly to a level of concentration the camera can no longer detect.

Environmental factors such as airflow in a space, wind and sunlight can reduce the chances of spread, as can such behavioral factors as mask-wearing and social distancing. The risk of exposure increases when people are not wearing masks and are close together in an enclosed space or in an area with poor ventilation.

Many of those circumstances will become more common as Americans increasingly spend time indoors in the coming months.