Coronavirus Technology Solutions
May 26, 2020
Mask Policy Review
Should we Rethink our Whole Mask
Policy?
Should task # 1 be to protect
individuals rather than keep
them from being spreaders?
Armbrust American Gearing Up to
Manufacture Billions of N95
Masks per Year
Draeger has Long Term Contract
to Deliver N95 Masks to HHS
CDC Approves Powered Air
Purifying Respirators
IQ Mask Uses HEPA Grade
Filtration Media
______________________________________________________________________________
Mask Policy Review
Should we Rethink our Whole Mask
Policy?
·
Medical personnel
are exposed to thousands
of times more COVID than others
but they wear N95 or even more
efficient masks and avoid
infection
·
60 choir members in Washington
State attended a 2 hour choir
practice but sanitized
everything and kept 6 feet
apart. 45 of them became
infected.
If they had worn surgical
masks maybe only 25 would have
become infected. If they had all
worn N95 masks none of them
should have become infected.
·
At a Southern China restaurant
where the air conditioner spread
COVID N95 masks could have
prevented the spread.
·
If those passengers on the
Diamond Princess isolated in
their cabins and inhaling
viruses through the HVAC system
had instead roamed the ship in
N95 masks they would have been
spared.
Should task # 1 be to protect
individuals rather than keep
them from being spreaders?
There are many arguments
to be made for and
against this new concept. They
all depend on facts which are in
dispute or not clearly
understood.
McIlvaine will be
conducting a webinar on
June 18 to discuss all of
the following
factors.
Virus Factors
·
The size and proliferation of
aerosols
·
The percentage of virus in
aerosols versus larger droplets
·
The viral load
·
Minimum infectious dose
·
Life of virus
·
Virus rejuvenation from dormancy
·
Creation of aerosols from
viruses leaving surfaces
·
Efficiency of various masks in
removing viruses
·
Various mask media options
·
Wash ability
·
Efficiency reduction over time
or with washing
·
Mask fit
·
Comfort
·
Breathability and oxygen
deprivation
·
Valve options
·
Killing as well as capturing
viruses
·
Age and immune response
·
Other medical conditions
·
Lung function
·
Activities
Environment
·
Virus load
·
Percentage of aerosols
·
Humidity
·
Air flow patterns
·
Benefits of capturing other
contaminants
Virus Factors
Size and proliferation of
Aerosols.
We breathe in millions of
particles per minute but must
avoid just 10 viral particles.
Small particles such as virus
aerosols are invisible. This can
provide a false sense of safety.
In every cubic meter of air we
inhale we also inhale 35 million
particles greater than or equal
to 0.5 microns in diameter.
We inhale even more
smaller particles in the
0.1 to 0.2 micron range
which is the size of the
virus.
The following table is designed
to rate cleanrooms.
ISO 14644-1 Cleanroom Standards
BS 5295 Cleanroom Standards
There are some reports that the
minimum infectious dose for
COVID -19 can be as low as 10
viral particles.
This means that if just a
tiny fraction of the particles
we inhale every minute are COVID
we can become infected. For
comparison purposes a
pharmaceutical cleanroom
typically is ISO 5.
The cleanest operating
theaters in hospitals are ISO 4.
The semiconductor industry
spends billions of dollars per
year to reach ISO 3. The task of
keeping small particles such as
viruses from occupying space is
very difficult.
Many of the particles we inhale
are long distance travelers. For
example mercury emitted from
gold mines in Brazil has been
traced to the Artic. When a
volcano erupted in Iceland the
skies turned dark in Europe for
weeks. Italian researchers have
found COVOD on air pollution
particles in the Lombardy
region. Another takeaway is that
social distancing has limited
effectiveness.
Viruses travel on
cigarette smoke sized particles.
So one way to view the
task is to think that everyone
you encounter is puffing away
and you have to avoid even
inhaling a few of his smoke
particles.
The percentage of virus in
aerosols versus larger droplets:
Viruses attach to
droplets or particles. They are
only 0.1 microns in diameter but
may be in droplets 20 microns in
diameter or larger. Droplets in
the 5 micron range can also be
generated or can be the result
of evaporation of larger
droplets. In medical changing
rooms in China higher viral
loads have been noted. Viruses
are also being aerosolized by
cleaning the floor or from other
surfaces.
Viral Load:
The viral load varies by
individual and activity.
A lusty super spreader
singer was able to generate many
thousands of aerosols and infect
45 people in just two hours.
Minimum Infectious Dose:
There are reports that only 10
viral particles is enough to
cause an infection.
Other views are that it
generally requires a large
number of particles over a
period of time. Since large
cough or sneeze droplets don’t
travel far, social distancing is
therefore the best way to avoid
infection. However, if small
numbers of airborne viruses can
cause an infection then a whole
different approach is needed.
Life of Virus:
The virus is known to remain
viable for hours in the air and
for days on various surfaces.
Virus Rejuvenation from
Dormancy:
It has now been documented that
viruses are not necessarily dead
but just dormant as they travel
through the air. They can then
penetrate the lungs where the
moisture revives them.
Creation of Aerosols from
Viruses Leaving Surfaces:
There are numerous cases
tracking aerosols which were
originally on surfaces such as
floors or clothing.
Mask Factors
Efficiency of Various Masks in
Removing Viruses:
Masks vary in efficiency
depending on the
media and the fit.
Viruses average 120 nm in
diameter but can be entrained in
droplets larger than 300 nm. In
general the efficiency improves
with more media which means
higher pressure drop. The
meltblown media used with most
N95 masks is electrostatically
charged which improves capture
efficiency.
The pressure drop impacts
breathability. It increases as
the square of velocity. So where
there is lots of leakage such as
the surgical mask with the gap
below, the actual pressure drop
is much lower than 2.5 Pa. this
is because much of the air is
bypassing the media. It is clear
that surgical masks with gaps do
not remove a big percentage of
small particles.
Most homemade masks are
even more inefficient.
In some cases a heavy
cotton fabric is by itself quite
efficient but with high
resistance it will cause more
air to bypass the mask. The
takeaway is that the masks being
worn by the public do not
protect against virus aerosols.
Table 1. Filtration Efficiencies
of Various Test Specimens at a
Flow Rate of 1.2 CFM and the
Corresponding Differential
Pressure (ΔP) across the
Specimens
The analogy can be made between
a garden house and a rainstorm.
If you only want to remove large
cough droplets its as easy as
dodging a garden hose wielded by
a baby.
If you want to stay dry
in a major storm that is very
challenging.
Various mask media options:
Surgical masks are made
mostly with meltblown
polypropylene.
The meltblown is
sandwiched between two layers of
spun bond media. There is an
electrostatic effect which
improves on the already high
efficiency due to the fine fiber
matrix. There are some new
meltblown designs with claims of
even higher efficiency at a
given pressure drop.
There are a number of
alternative materials which are
now available commercially. They
include nanofiber membranes
which are claimed to have higher
efficiency at a given pressure
drop.
They are also washable.
The media is available in large
quantities.
In the case of Cummins
the offering is based on media
originally designed for
filtering engine air intakes. In
the case of Ahlstrom it is the
use of surgical drapes. Berry is
another supplier diverting media
used from other applications.
Efficiency:
Some of the newly available
media has efficiencies rated at
N99 or better. 3M already offers
a range of options higher than
N95 using meltblowns.
The question of a carbon
layer and its impact on
efficiency also needs to be
addressed.
Wash ability:
N95 masks with meltblown media
can be decontaminated with UV
light, H2O2 , or other means.
Battelle reports ten time
successful reuse of masks
decontaminated with H2O2.
Masks made with membrane
materials can be washed by
various means and reused many
times.
This reuse ability
results in a better tight
fitting mask with an affordable
cost per use.
Efficiency reduction over time
or with washing:
The support structure as well as
the mask media can deteriorate.
The ability to separate the
media and support structure
means that the structure can
provide longer term use.
Mask Fit:
The mask fit is critical to
providing protection. The more
expensive reusable masks can
provide that fit.
Comfort:
N95 masks without valves but
with a tight fit are
uncomfortable to wear for long
periods. The medical worker can
endure the discomfort for a
shift but it is unrealistic to
think that
people will wear N95
tightfitting masks without
valves throughout the day
without serious negative
impacts.
Breathability and oxygen
deprivation:
With a tight fitting N95 mask
the quantity of air inhaled is
down as much as 25%.
Some CO2 is re-entrained
in the new breath. Two Korean 14
year olds
who were required to run
in 1000 meter tests with their
masks on died last month on the
track.
The government has since
suspended the requirement.
Valve options:
There is a large industry which
has flourished for many years.
Masks with valves are purchased
by those wanting
to protect themselves
from air pollutants. In China
there are Vogmask stores where
all they sell are dozens of
varieties of highly efficient
designer masks.
They are equipped with
one way valves which allow the
air to be exhaled through the
valve.
Millions of people have been
wearing these valve masks to
protect themselves without
concern about their potential
contamination of others. Why is
this not an important model for
us to use going forward?
Killing as well as capturing
viruses:
A number of media designs
incorporate silver or other
materials which will kill
bacteria and viruses.
Wearer factors
Age and immune response:
The use of masks by the elderly
is conditioned on the
breathability.
It is unlikely that
anyone with reduced lung
function or heart problems could
wear an N95 mask without a
valve. Shouldn’t the type of
mask be dictated by this need?
Should the elderly be deprived
of efficient masks because
valves are prohibited?
Sacramento says:
Masks with valves are
prohibited.
Lets consider mask
recommendations by segment and
not as one.
Other medical conditions:
Those with impaired immune
systems can probably justify an
N99 Mask and tight fit. This
will require use of a valve. The
tight fit is also a function of
the valve. If you are blowing
air out around the edges of the
mask you tend to expand the
opening.
Lung function:
The lung functions vary among
individuals creating an
important variable in mask
selection.
Activities:
Any job function involving
physical labor including many
meat processing jobs needs to
take into account the importance
of wearing a mask which does
slow down oxygen intake.
Environment
Virus load:
The wearing of masks can be
tailored to the viral load and
therefore the risk.
There is a movement to
develop a N-80 mask which would
be less efficient than the N95
but more efficient than the
typical surgical mask.
Individuals could have all three
mask options available.
They could decide where
it is most appropriate to not
wear a mask or to wear the N80
or N95.
Percentage of aerosols:
The danger at any
point in time is a
function of the percentage of
the total viral load which is in
the form of aerosols.
Humidity:
In general higher humidity
deters the virus when it
arrives. The virus travels
shorter distances in humid air
than in dry air where the
droplet size is smaller.
Air Flow Patterns:
The viral load is in part
determined by air flow. This
important subject is dealt with
in a separate analysis.
Benefits of capturing other
contaminants:
The coronavirus pandemic will
subside at some point in time.
There will be uncertainty about
when and if it will return.
Wearing an N90 mask may become
as much a habit as drinking
bottled water. Everyone is
subjected to high air pollution
levels at some point in time
during the year. In some
countries this is a daily
occurrence. But even in others
the mask will be justifiable. St
Louis was meeting its
particulate ambient emission
goals and was assumed to be
meeting its toxic metal goals
which had been shown to track
the total particulate. However,
when the city installed monitors
to directly measure toxic
metals, they found spikes on
days when the wind blew from the
direction of a lead refinery.
Hospital acquired infections
cause 1.7 million illnesses and
99,000 deaths per year in the
U.S.
Patients would be well
served to wear N95 masks
Mask Webinar on June 18 to
Launch Debate on Protecting
Wearer as Well as Those at Risk
A webinar will be held on
January 18 at 10:AM CDT to
discuss and debate the
proposition:
Mask selection should
be based on wearer needs first
and then on needs of those at
risk.
This proposition is in conflict
with certain ordinances which
prohibit masks with valves.
It challenges
conventional wisdom. However,
the general premise that all
individuals if protected by
highly efficient masks could
lead near normal lives would be
of high importance to world
economic recovery. The support
or rejection of this proposition
rests on determination of the
following factors
Virus factors
·
The size and proliferation of
aerosols
·
The percentage of virus in
aerosols versus larger droplets
·
The viral load
·
Minimum infectious dose
·
Life of virus
·
Virus rejuvenation from dormancy
·
Creation of aerosols from
viruses leaving surfaces
Mask Factors
·
Efficiency of various masks in
removing viruses
·
Various mask media options
·
Wash ability
·
Efficiency reduction over time
or with washing
·
Mask fit
·
Comfort
·
Breathability and oxygen
deprivation
·
Valve options
·
Killing as well as capturing
viruses
Wearer Factors
·
Age and immune response
·
Other medical conditions
·
Lung function
·
Activities
Environment
·
Virus load
·
Percentage of aerosols
·
Humidity
·
Air flow patterns
·
Benefits of capturing other
contaminants
Insights are encouraged in
advance and will be made
available at the time of
webinar. These insights
should address the factors and
what is already said about them
in the background document.
The session will be in a
discussion format with each of
the factors reviewed as
warranted.
Send your comments to Bob
McIlvaine
rmcilvaine@mcilvainecompany.com
847 226 2391.
Cambridge has an Efficient and
Comfortable Mask but with Valve
The
pro mask uses a unique triple
filter system which has been
tested by Nelson and reaches N99
efficiency levels.
The
first layer of the filter system
catches larger pollution
particles such as dust and PM10.
It’s then backed up by the
Three-Ply Micro Particulate
which stops nearly 100% of
smaller particulate matter such
as PM2.5 and PM3.0.
The
inner filtration layer is made
from 100% pure activated carbon
cloth, originally developed by
the UK Ministry of Defense for
chemical, biological, and
nuclear warfare protection.
The
carbon filter is treated with
silver to ensure 99% of harmful
pathogens are removed and
killed.
The filter material is comprised
of a series of activated carbon
filaments, each about 2,000
nanometers in diameter. Each
filament is many times smaller
than the typical grain size in
standard carbon materials,
making the rate of adsorption of
pollutant gas much faster and
therefore more powerful. It also
means that bacteria and viruses
are drawn to the filament
surface much more efficiently,
because there is so much more
available surface than in a
granular carbon.
The high number of filaments –
spun into a yarn and then woven
into cloth – makes the speed of
adsorption extremely fast in a
material that is still easy to
breathe through. Not only are
molecules such as pollutant
gases and endotoxins quickly
adsorbed into the pores from a
much wider area, but the Van der
Waals forces also attract and
immobilize on the filament
surface much larger particles
including bacteria, which often
have a negatively charged
membrane. Together with the
anti-bacterial silver added to
the filament surface, the
activated carbon cloth traps the
bacteria and draws out the
gel-like cytoplasm inside –
killing it and preventing
infection.
Cambridge uses
British military
technology developed for
chemical, nuclear, and
biological warfare in the mask
that’s manufactured in the UK.
But the masks are assembled in
Indonesia and China.
Masks Performance Comparison
Armbrust American Gearing Up to
Manufacture Billions of N95
Masks per Year
Last week, Armbrust
American, announced the
close of a $5
million dollar investment
round, and the official opening
of their Austin,
TX-area manufacturing
facility.
The factory is currently ramping
to produce 1.2 million masks per
day, and Armbrust
American has plans to
scale production to billions
annually if needed.
Armbrust American says it can
offer masks cheaper than Chinese
suppliers, so that American's
don't have to choose between
Made-in-America quality and
price. Individuals can
purchase Austin, TX Made Medical
Masks for $0.50 on Armbrust's
website, with plans to bring
prices down as production
increases.
"Our Austin, TX lab uses
automation to turn raw materials
into quality surgical masks,"
said Lloyd
Armbrust, CEO. "And
because we are so space
efficient, we are even prepared
to install unused assembly lines
for the next potential crisis;
making sure that America is
never without the protection we
need."
When you click on the
website to purchase you receive
this message “This is a
pre-order for a TEN (10) pack of
our N95 masks that are pending
NIOSH approval.
The United States has very high
standards for what we sell.
Because of this, the approval
process can take a very long
time. We have spent the last
five months designing and
building our masks, and only
recently received FDA
Registration.
We can now sell our Medical-Grade
Facemasks made
in Austin, TX--but we cannot
move forward with selling our
N95 masks until we receive NIOSH
approval from the CDC.
The NIOSH approval process for
selling N95 masks in the United
States can take up to six
months.
This order for a 10 pack for $39
will not ship until we receive
NIOSH approval which is expected
as early as September 2020.
This
order will help us gage public
interest and allow us to pre buy
automated lines for our N95
masks. This means that as soon
as we receive approval, we can
ship your mask.”
Draeger has Long Term Contract
to Deliver N95 Masks to HHS
The U.S. Department of Health
and Human Services (HHS) issued
an award to Dräger for the
supply of National Institute of
Occupational Safety and Health
(NIOSH) approved N95 respiratory
protection masks at the end of
March. The contract is part of
the recent government
announcements concerning the
supply of masks. As part of the
contract Dräger plans to
increase U.S. domestic
production of the masks and
expand its manufacturing
footprint over the course of the
contract. Deliveries will take
place over the next 18 months
with a focus on accelerated
supply wherever possible.
“Respiratory protection has been
at the core of our capabilities
for over 110 years. Our N95 mask
design offers superior comfort
and breathability and is
certified to the NIOSH standard
for particle respiratory
protection,” said President and
CEO for Dräger in North America,
Lothar Thielen. “This contract
comes in addition to the ongoing
work we are doing to protect
frontline personnel in the fight
against the pandemic. We are
humbled to be able to support
healthcare professionals and
first responders with our Technology
for Life, which spans both
healthcare and safety
applications. In addition we are
proud to further increase our
U.S. investments and
manufacturing base in support of
this contract.”
Dräger is an international
leader in the fields of medical
and safety technology. Our
products protect, support, and
save lives. Founded in 1889,
Dräger generated revenues of
almost EUR 2.8 billion in 2019.
The Dräger Group is currently
present in over 190 countries
and has more than 14,500
employees worldwide
CDC Approves Powered Air
Purifying Respirators
NIOSH-approved respirators are
available in many types, models,
and sizes from many
manufacturers for a wide variety
of uses in many occupational
settings. The most common types
of respirators in healthcare are
N95 filtering facepiece
respirators (FFRs), surgical N95
FFRs, and PAPRs.
Of these three options, many
healthcare practitioners are the
least familiar with PAPRs. A
PAPR is an air-purifying
respirator that uses a blower to
force air through filter
cartridges or canisters and into
the breathing zone of the
wearer. This process creates an
air flow inside either a
tight-fitting facepiece or
loose-fitting hood or helmet,
providing a higher assigned
protection factor (APF) than the
reusable elastomeric non-powered
air-purifying half facepiece
(half mask) or N95 FFRs. A PAPR
can be used for protection
during healthcare procedures in
which HCP are exposed to greater
risks of aerosolized pathogens
causing acute respiratory
infections.
A PAPR may have a tight-fitting
half or full facepiece or a
loose-fitting facepiece, hood,
or helmet. It has an OSHA APF of
at least 25 for loose-fitting
hoods and helmets, 50 for
tight-fitting half masks, and
1,000 for full facepiece types
and some loose-fitting hoods and
helmets where the manufacturer’s
testing has demonstrated an APF
of 1,000.
CDC has published
recommendations for HCP
respiratory protection and of
commonly used NIOSH-approved,
FDA-cleared, single-use
filtering facepiece N95 surgical
respirators. Properly fitted FFR
and half facepiece reusable
elastomeric respirators are
expected to reduce exposures to
one-tenth of the concentration
that is in the air, based on
OSHA’s APF of 10 for these
respirator types. All PAPR APFs
exceed the APF of 10 for N95 FFR
or elastomeric half facepiece
respirators.
PAPRs reduce the aerosol
concentration inhaled by the
wearer to at least 1/25th of
that in the air, compared to a
1/10th reduction for FFRs and
elastomeric half facepiece
air-purifying respirators. OSHA
assigns an APF of 1,000 to some
PAPRs with hoods or helmets.
However, employers must have
evidence provided by the
respirator manufacturer that
testing of these respirators
demonstrates performance at a
level of protection of 1,000 to
receive an APF of 1,000. Absent
such evidence, PAPRs with
loose-fitting helmets or hoods
have an APF of 25. When used
properly, PAPRs provide
increased protection and
decrease the likelihood of
infection transmission to the
wearer as compared to FFRs and
half face reusable elastomeric
respirators.
A variety of NIOSH-approved PAPR
designs are available. Examples
include those with tight-fitting
facepieces and loose-fitting
hoods or helmets, blower styles,
battery types (e.g., Lithium
ion, Nickel-Metal hydride,
Nickel Cadmium) or
over-the-counter disposable
batteries, and high efficiency
(HE) filters or filter
cartridges. HE filters are
99.97% efficient against 0.3
micron particles. A PAPR may
have adjustable air flow rates
for added comfort and a range of
cartridge protections some of
which are solely for
particulates (HE filters) and
others which also protect
against chemical gases and
vapors that can be used to help
protect against hazards
associated with the handling of
certain hazardous drugs and
cleaning/disinfecting
operations. The substantial PAPR
product diversity provides
flexibility to customize
protection needed in a
healthcare setting.
IQ Mask Uses HEPA Grade
Filtration Media
IQAir Mask features a unique
exhaust valve design with
an ultra-thin valve membrane for
low air resistance and immediate
air exchange. Many air pollution
masks use ineffective material
that wears out quickly due to
moisture build-up and high
filter material resistance –
IQAir Mask ensures an even
exchange of inhaled clean air
and exhaled breaths while
reducing moisture and CO2
build-up inside the mask to
prevent drowsiness, headaches,
or loss of energy.
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