FAQ on Medical PPE, Facemasks, N95, etc.

These are my personal views and not that of any employer. The best resource on this is the summary from the Smart Air Filters website by their CEO, Paddy Robertson.  If you want to approach problem solving in manufacturing – start with Goldratt.


Do you know that healthcare providers and hospitals need masks?

Yes, we do! Every part of the global mask supply chain has been running flat out since late 2019, when the seriousness of the Corona virus outbreak became clear. Materials are moving through the supply chain as fast as they can.

I’d like to buy what the mask makers buy, when can I get some?

Right now, every plant I know that is part of this supply chain is running flat out. Rolled good plants can’t keep up with orders. Facemask plants can’t keep up with orders. This is an efficient supply chain with experienced, professional manufacturers that know how to get the most out of their people and plants. With the current public health emergency, most companies are not taking on new orders. The fastest way to get materials out is to follow the current path.

If a roll was sold to you, it would be like taking a mask away from a physician that really needed it.

I’m with a hospital that really needs some, can you ship me something?

Hospitals should be reaching out to distributors or to mask makers. A hospital spending its time looking for rolled good inventory is wasting its time. Focus on getting the next nearest shipment of masks.

Mask Specific Questions

I’m going to use HEPA filters since that is the highest standard – won’t that work?

HEPA is both a standard for completed filter elements used in wafer fabs, flat panel TV production, and drug making, as well as a commercial claim. For the HEPA standard, most filters are made of wetlaid glass fibers or they use PTFE – material similar to that used in Gore-tex jackets. Both of these materials have very low air permeability – healthcare workers could not breathe through them! While they would be very efficient, physicians would have to move the mask to breathe, making the whole exercise pointless.

There are commercial HEPA-claim filters (not ‘True HEPA”) that use charge to get higher efficiencies. For more on charge, see below.

I need polypropylene HEPA fibers, do you have them?

Fibers can’t have a HEPA claim – it is only used on the finished HEPA element. As discussed above, polypropylene (“PP”) is not used in HEPA.

I may have the material wrong, we are looking for the HEPA filter material that does uses a polymer instead of fiberglass?

Your options would then be to use a PTFE – which would also not be breathable. There are very small volumes of materials with synthetic HEPA on the market. They would be difficult to use in a facemask.

We’ve seen rolls marketed online, but we haven’t been able to secure any in a timely manner?

Almost every government globally is struggling to get appropriate PPE for their healthcare workers. I would not believe that a container will leave from a foreign site and get to your location. If you did receive a roll, I would expect it to be a grade that is not commercially relevant to your work.

What can we do then?

I’d follow the guidance here and make:

  • a form fitting mask
  • using two layers
  • that somehow incorporates charge –
    • Use a pocket to include a swiffer refill
    • make one of the layers wool, or some other ‘static-y’ material

American Based Manufacturing Questions

Why did all of the manufacturing go to China?

My personal impression is that the capitalist pressure to ‘maximize’ shareholder return did not line up with a common-sense appreciation that in times of needs, a culture needs to be self-reliant. Beth Macy’s excellent book Factory Man, shows how the US effectively traded the jobs of millions of Americans in exchange to help bring China out of poverty, but this trend continued to the point of absurdity.

Doesn’t that make you angry?

There are news stories about angry participants in this supply chain, but my view is that it makes me feel more sad than upset. Even now the cries of, “we don’t know how to do this in America” – c’mon. Yes, we do. It is just a skill that has been ignored.

What other products are made with these materials?

Nonwovens are used in many industries. They are used in wound care, in car production, as surfacing veils for aerospace, and as crucial components in filter elements for the production of pharmaceuticals and drinking water.

Does everyone know hospitals need masks?

Yes!  Everyone who works in the medical PPE supply chain is working overtime and doing everything they can to push masks out to the hospitals.  There is a lot of PPE still made in the US, and that includes not only facemasks, but also gowns, medical barriers, the filters used in the ICU, and the filters in cartridges.  

How does the mask supply chain work? 

There are two main parts to the supply chain:

Rolled Goods.  Rolled good makers buy polymer – mostly polypropylene – and use it to make a nonwoven.  Several layers of nonwovens are then brought together by the next step in the supply chain, to make the mask.  The efficiency layer in a facemask is most often a charged meltblown.  

Converters.  Facemask makers receive rolled goods (sometimes in rolls that are 2 meters wide and kilometers long), and then convert them into facemasks.  Surgical masks are sewn.  N95 (NIOSH masks), and their cousins R95 and P95 (where R indicates some oil Resistance and P indicates even more) are thermo-formed and are more form fitting.  

What do you think about the recent 3M news increasing output to 100 million per month?

That’s great news.  I’d interpret that to mean that a converter, with some vertical integration – 3M and others make some Rolled Goods, but not all – is now capable of shipping 100 million masks per month.  Mask makers are often the constraint in the supply chain. The automated production lines that make masks are mechanically complex and can take a long time to build. Nonwovens lines tend to be larger and are used for many different end markets. For Nonwovens lines, it tends to be more an issue of pivoting the line to make this specific kind of material, and ensuring you can hit the standards of the grade that is required.

Why is getting masks to hospitals so hard?

The supply chain started running very aggressively as demand ramped in Asia in Q4.  China is a face mask exporter, and as China shut down its production, there was a double hit to production.  US demand was called up to not only service US demand, but to also export (before Corona crossed to the US).  Chinese supply has only come back slowly, many plants there are still closed – it is not clear if they have capacity to export now.

If anything the supply shock of China shutting down prepared the US supply chain to be ready, now all that capacity is being redirected here.

What guidance would you share to help medical professionals in the event of shortage?

Cough droplets from patients with corona virus are a safety issue.  The atmosphere is contaminated with an unsafe particulate; cough droplets full of corona virus generated by sick patients.

  • Declare war on the droplets.  Droplets are 100 micron – 5 micron in size. Follow common indoor-air quality and safety protocols.
  • Use room air cleaners.  
  • Use whatever PPE you can.   (DysonCamfilAustin Air, etc.)
  • Never use a wet facemask – wet helps the virus travel through the mask.
  • Look for ways to get charge into the mask.

How do charged masks work? 

Charge in the fibers – static electricity – attracts the particles as they flow through the mask.  This improves the masks efficiency.  Without the charge, most masks have very low efficiency.  For very small particles – 0.3 micron and smaller, polypropylene meltblown masks only work because of the charge.  

Does the charge attract viruses to my mouth?  

No – but that’s a good question.  The charge is very weak.  Think of the dangerous particle drifting in an ICU Room – it has many forces exerted upon it.  When a mask wearer inhales, that force draws the particle towards the wearer’s lungs – rather than pass through the mask, the charge acts as a special force that pulls the dangerous droplet to contact the mask.

What materials have charge that I could use?

Swiffer replacement refills have charge.  Wool has charge.  Anything that has static electricity naturally could be useful to use.  

What steps would you suggest so this does not happen again?

MAP THE SUPPLY CHAIN. I’d make a very clear map of the supply chain. 

  • Know every hospital
  • Know every distributor that sells to those hospitals
  • Know every mask maker that uses those distributors
  • Know every rolled good / nonwoven maker that sells to those mask makers

1. Canada had an inventory of N95 masks that had dry rotted.  Pay for a study of how to extend mask shelf lives.

2. Store inventory.  Make up fresh rolled good inventory every X years, such that it can be quickly converted to masks.

PRE-PURCHASE CAPACITY AND CAPABILITY. Pay for facemask capacity. Production equipment for masks is notorious for losing money.  Have the gov’t or other group buy equipment and pay some modest fee to have it maintained and ready for use.  

BAD IDEAS. Don’t invest in a horde of inventory.  Invest in systems and processes that can handle a future threat of unknown size and scope.  For instance, NC State was going to get a Nat’l Academy center of excellence on advanced PPE, that was never funded even though it was approved.  That would have had small volume production, but most importantly, it would have produced 100s of grad students with work experience in these fields.  As a culture we have not produced many people who can answer these questions.  

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