Open ajlennon opened 4 years ago
ajlennon
commented
4 years ago Slightly off-topic but there is also this link on cleaning N95 masks
"Duke University uses vaporized hydrogen peroxide to clean N95 face masks for reuse"
https://twitter.com/evankirstel/status/1243957616914685953
More on this (Sorry, it's the Mail, I know but...)
ajlennon
commented
4 years ago @markmellors commented on Twitter in relation to the "Futura Sciences" mask that
this face mask design is snake oil. I've tweeted replies to a few people about it, as have many leading 3d printer experts. in short: poor sealing, high filter pressure drop, no proof of reuse. worse than a cloth mask
ref: https://twitter.com/MarkMellors/status/1243963421546201089?s=20
ajlennon
commented
4 years ago The pinned tweet at the top of @realsexycyborg 's timeline has this to say
Why not 3D Printed masks: https://twitter.com/RealSexyCyborg/status/1240737164654047232 Why cloth masks for the public and N95 for Health Care Workers:
ref: https://twitter.com/RealSexyCyborg/status/1241611801390874624?s=20
ajlennon
commented
4 years ago @JackiePease sorry to duplicate your issue. Looking at what @realsexycyborg is saying can we reach out to the fabric / sewing community for advice and help?
markmellors
commented
4 years ago To avoid duplication, I've reviewed a bunch of designs for various challenges here:
https://docs.google.com/spreadsheets/d/1IpP0RV0dE5zKPK88EAz2shHbk8pkFB0kyJwnrUkHyUg/edit?usp=sharing
which highlights the issues and the ones I think are best at this time.
I'm currently trying to concentrate my efforts on teh visors, as I know we can produce something that meets the required standards. I spent a week looking at filtering masks and couldn't come up with anything better than a sewn cotton surgical style mask.
Key constraints:
ajlennon
commented
4 years ago I had this feedback from Alyssa Alabassi (Surgeon)
To return to the article you sent me and the question attached to it. Yes, opinions are divided regarding the usage of masks in the general population. However the initial slogan in the campaign referred to tissue usage rather than cloth handkerchiefs. People are more likely to forget to wash a cloth mask than to bin a tissue one. Cloth masks can easily become an infection portal, so no to cloth masks. Personally, I think people should wear basic tissue masks (not N95masks) to reduce droplet splatter from themselves and to avoid getting splatter from others. There are a lot of people who have no symptoms but carry the disease so impossible to know who's infected and who's not! It also reduces people's tendency to touch their faces which increases infection risk.
It's a personal opinion but based on what's been written so far and related facts. Absolutely, what the general public can use and what the NHS should use are different but unfortunately, even in the NHS, many nurses and doctors aren't using basic tissue masks in an outpatient setup. Neither are GPs, which increases their likelihood of catching the virus from someone with no symptoms and either getting infected themselves or passing on to others.
In a basic clinical setting, such as outpatient departments and GP surgeries (not seeing covid patients), even pharmacists and other public interfacing services, a face shield (transparent and allows easier communication) is better than nothing at all and reduces splatter related infection risk.
The comments on face shields in the wider community also relate to issues #6, #9
As you can see, the guidance is for contact with Covid confirmed cases and those performing intervention on Covid patients. General nursing and medical staff are not included. With such a contagious virus and the fact that many don't display symptoms, an extra layer of protection needs to be considered
ajlennon
commented
4 years ago ajlennon
commented
4 years ago This feedback from "The Purple Stitcher" @Madscouser
There's lots of different mask patterns out there, my 1st suggestion would be getting a medical person to advise which would be best. This one has a waterproof barrier in the middle, which seems a good idea to me but I'm not medical, so not sure! https://m.facebook.com/story.php?story_fbid=10163087817675562&id=756880561
JackiePease
commented
4 years ago I DMd Cathy about this as well. Her response is also that we need to be sure of what we're doing, but seems happy to help: "Yes that sounds good as long as we would be adhering to the regulations, I have calico here but not sure if there's regs on which fabrics to use, I've also got bits of cotton fabrics in colours and prints The only thing is i only have aboit 4.5 metres of thin elastic so that wouldnt get me very far. Could anyone provide the elastic and materials?"
ajlennon
commented
4 years ago Maybe we should add a face mask consumables section into - https://github.com/DoESLiverpool/covid19/issues/21 ?
amcewen
commented
4 years ago Dunno, getting some medical input on a design seems more useful first? Maybe @afroleft can see if any of the medical people he's been talking to have any opinions on masks?
ajlennon
commented
4 years ago Agreed - but as with the 3D Printing and Laser Cutting I am guessing there are some consumables we know we will need even though we're not sure of the designs.
epsaul
commented
4 years ago I'm not an authority but you can buy HEPA filter vacuum cleaner bags which may (or may not?) be a suitable material specification for viruses. There is also a duckbill pattern on the internet and people are making these in fabric. This is reportedly a good fit but I think if you used the hoover bags (HEPA spec) for the fabric this would maybe be a way to go.
JackiePease
commented
4 years ago I think it's a bit less clear at the moment - there are a much bigger range of materials that could be used, from medical mesh to old T shirts. If we can get an opinion from the potential users quickly I think we'd be better off waiting
From: Alex Lennon notifications@github.com Sent: Sunday, March 29, 2020 6:45:52 PM To: DoESLiverpool/covid19 covid19@noreply.github.com Cc: Jackie Pease jackiepease@hotmail.com; Mention mention@noreply.github.com Subject: Re: [DoESLiverpool/covid19] Can we produce a face mask (i.e. not the eye protection visor) (#17)
Agreed - but as with the 3D Printing and Laser Cutting I am guessing there are some consumables we know we will need even though we're not sure of the designs.
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ajlennon
commented
4 years ago Gotcha - OK
ajlennon
commented
4 years ago Information on mask designs via @SayBeano
https://m.facebook.com/story.php?story_fbid=2962276270503347&id=403061379758195
TheSmallLebowski
commented
4 years ago I'm in no way an expert and I'm coming from a dressmaking background not a scientific one, but from what I can find online it seems a non woven material is what's needed. The medical masks are made from a type of polypropylene. I have sourced 20 metres of this and plan to make some to give out, possibly to homecare agencies who go into the houses of the most vulnerable and seem to be in woeful short supply of masks.
Other thoughts I had were maybe using a cotton but ironing a light/medium interfacing to it before cutting... I think interfacing would be appropriate as I believe it is also non woven but I need to research that more to be certain.
I thought they would at least be useful to people who are going out shopping for other vulnerable friends and family, just to minimize risk if they couldn't be used in a medical capacity.
TheSmallLebowski
commented
4 years ago I'm not an authority but you can buy HEPA filter vacuum cleaner bags which may (or may not?) be a suitable material specification for viruses. There is also a duckbill pattern on the internet and people are making these in fabric. This is reportedly a good fit but I think if you used the hoover bags (HEPA spec) for the fabric this would maybe be a way to go.
Apparently these are one of the best in terms of filtering, but not easy to breathe in 🤷🏼♀️
JackiePease
commented
4 years ago Comment from @kayascott via email (she's currently having difficulty commenting on GitHub): "I would like to get involved on the textile side of things... I can offer time and stitching... I have recently seen this video from a Dr Ryan Southworth, Emergency Dr in the US and his wife, about making the duck bill facemask with hepa filter vaccuum bags... https://m.youtube.com/watch?feature=youtu.be&v=W6d3twpHwis For use in hospital..
Re sterilising: Hairdressers should have autoclaves for sterilising equipment, nail and Beauty salons, tattoo and piercing studios should, and I think dentists... Could be worth checking out how suitable this method would be. I am sure if suitable a call out to get hold of a couple to ensure all fabric masks are sterile before distributing? Not sure if they would be suitable for the visors though.
While trying to find out about suitability of autoclaving for sterilising the fabric masks I came across an article which talks about making masks from the fabric surgical instruments are wrapped in when being sterilised (brand name Halyard H600) https://www.healthcarepackaging.com/home/article/21124863/second-life-sterile-wrap-fashioned-into-masks."
SayBeano
commented
4 years ago I'll reach out to tattooists today to see if any are prepared to to loan autoclaves should they be needed
JackiePease
commented
4 years ago I've given @Madscouser and @kayascott details to Cathy, as she and Mary are separately organising sewing of scrubs and hopefully masks too:
https://m.facebook.com/story.php?story_fbid=10221412229284946&id=1526123237
It would still be good if we could use NHS contacts to find out what kind of masks are useful - Mary believes they need to be disposable
I told Cathy that we could probably find other sewers by publicising on @doesliverpool social media
amcewen
commented
4 years ago @JackiePease Ace! @afroleft is probably best places for finding things out from NHS contacts. I'll aim to ask when I'm talking to any too though - the local procurement guy I spoke to earlier did say they were currently using masks that were 4 years out of date, and they have been re-using other PPE that's supposed to be single-use, but that'll be easier with something like a visor...
huffeec
commented
4 years ago @JackiePease Helen has been to collect one of our sewing machines to help out with this. We're thinking that even if there isn't a clinical use there will be community channels that could distribute them for individuals to use. Will keep a watch on this thread for any updates on a preferred design/materials.
helenpstephens
commented
4 years ago Hi there. Been testing out a couple of designs from online tutorials to see which are easiest, quickest to make, comfortable to wear etc. A lot of suggestions are to mske masks with a pocket to insert a filter material inbetween which can be changed regularly throughout the day. Filters can be made easily from dried out wet tissue/toilet roll (depending on how easy it is to get hold of these days). Both main styles (pleated and wjatever the other style is called) have designs that include a pocket layer. The walton centre has just put a call out for masks for healthcare workers, I'll respomd and see what they advise.
ajlennon
commented
4 years ago @helenpstephens feels like it would be good to get feedback from somebody who knows about whether this is true
ref: https://medium.com/@thejanellemj/please-join-me-in-wearing-a-mask-71e0e3f4fe4a
JackiePease
commented
4 years ago Great - @helenpstephens - would you like me to put you in touch with Mary and Cathy who are looking into this? Also, is that a sewing machine from Sandbox or DoES Liverpool, and which one?
helenpstephens
commented
4 years ago That'd be great @JackiePease. The sewing machine is from Sandbox. It's a Viking. I'm still getting used to it.
helenpstephens
commented
4 years ago Quick update: Walton Centre has a strategy meeting tomorrow and they're going to discuss their needs and what sort of specs we need to work to, if fabric masks will be of any use to some of their staff. I'll report back tomorrow when I hear more.
KayaScott
commented
4 years ago Breaking my heart, net's lot just think about the NHS...this is a message from a friend of mine who has previously had a heart attack, is recovering from breast cancer, should herself be at risk and isolating, caring for a Mum with Alzheimers..... My Mum and Dad been on lockdown for over a month. My brother heard disturbing things from a consultant and rang me . We told them to isolate and they have . Me or Steven do their shopping and leave on step they look amazing and don’t seem phased . Iam in a nursing home doing behavioural observations for continuing health care . It’s a clinical nursing unit so a strict infection control regime . Temp taken on arrival and form everyday . No cases so far. The thing is we may be running out of protective stuff soon as it’s all going to the hospitals but they are trying to force care homes to take in covid19 cases too . They are not taking anyone over 65 into hosp . It’s really scary and going to get worse. Was thinking maybe you could make some aprons or poncho type covering ours our so flimsy. Face screens too I have goggles but most staff have none x Working 6 days a week we have no staff .
It not good just hope and pray they can come up with a vaccine x
tamhamilton
commented
4 years ago I'm in no way an expert and I'm coming from a dressmaking background not a scientific one, but from what I can find online it seems a non woven material is what's needed. The medical masks are made from a type of polypropylene. I have sourced 20 metres of this and plan to make some to give out, possibly to homecare agencies who go into the houses of the most vulnerable and seem to be in woeful short supply of masks.
Other thoughts I had were maybe using a cotton but ironing a light/medium interfacing to it before cutting... I think interfacing would be appropriate as I believe it is also non woven but I need to research that more to be certain.
I thought they would at least be useful to people who are going out shopping for other vulnerable friends and family, just to minimize risk if they couldn't be used in a medical capacity.
Can you link to the material you found, and your source, please? Thanks in advance
TheSmallLebowski
commented
4 years ago I'm in no way an expert and I'm coming from a dressmaking background not a scientific one, but from what I can find online it seems a non woven material is what's needed. The medical masks are made from a type of polypropylene. I have sourced 20 metres of this and plan to make some to give out, possibly to homecare agencies who go into the houses of the most vulnerable and seem to be in woeful short supply of masks. Other thoughts I had were maybe using a cotton but ironing a light/medium interfacing to it before cutting... I think interfacing would be appropriate as I believe it is also non woven but I need to research that more to be certain. I thought they would at least be useful to people who are going out shopping for other vulnerable friends and family, just to minimize risk if they couldn't be used in a medical capacity.
Can you link to the material you found, and your source, please? Thanks in advance
https://www.ebay.co.uk/itm/353019923652
Still waiting for it to arrive but it's coming Royal Mail and I think they are very pushed at the minute. It was due to arrive on the 4th. I can update on suitability when it does finally get here, really hoping that's today!
tamhamilton
commented
4 years ago Thanks for the link!
I just did a bit of reading into this, and found the following... The material correct to the N95 spec is generally called 'N95 nonwoven (or melt-blown) polypropylene'. It is also known as BFE 99 (>99% Bacterial Filtration Efficiency). There are also N99 and N100 fabrics which exceed the N95 spec. P2 and P3 filters are equivalent to N95 and N99 respectively, as are FFP2 and FFP3.
Nose wires are generally ~0.6mm galvanised iron (that's a paperclip to you and me!), or ~0.5mm stainless steel (thin MIG welding wire might work), or 0.5-0.8 x 3-5mm soft (annealed) aluminium strip.
To comply with N95 spec, the finished mask must also achieve <8% inward leakage. N99 spec requires <2%. Of course this is probably impossible for us to measure, but it gives a decent indicator of how snug the fit of the mask needs to be. Surgical style masks generally offer about 60% filtration efficiency (compared with 95% efficiency of the N95), so I'd guess they're achieving around 30% inward leakage.... So nose wires really do make a huge difference!
Just in case anyone was unsure, N95 is the minimum spec which seems to be universally recommended as being decently effective against Covid. Other masks are probably better than nothing, if used/worn/sterilised/disposed of properly, but N95 is what we should be aiming to produce.
I hope that's helpful!
TheSmallLebowski
commented
4 years ago Yes very helpful thanks, I have found it all a bit confusing! So mine is meltblown, which is good. But couldn't find any when searching that actually said n95 that was actually available.. My plan for mine is to make them for home care workers/key workers as I know they are not really being thought of or have been allocated a woefully short supply.
I'm still looking for a reusable solution though, not sure if polypropylene or any non woven stands up to a 60° wash.
Must say this is all a bit of a baptism of fire, I'm much more used to making underwear, housewear type things that I want to be breathable 🤷🏼♀️
TheSmallLebowski
commented
4 years ago Oh also, I am wondering whether rolls of aluminium/stainless steel wire strip for nose covering could be bought on a roll from Screwfix/tool station or other hardware store still operating as a click and collect. I'm trying to limit my online orders now as post service completely under pressure now.
helenpstephens
commented
4 years ago I started making mine really just for people generally, to give them a bit of added protection when they go shopping. Although since I started, I got requests from pharmacy staff and foodbank volunteers. I've just focused on a 2 layer cotton design on the basis that some protection is better than nothing and no one on the frontline, working with sick people will be using them. But getting people to keep them on when they're not used to wearing them means they do need to be comfortable and breathable. I made some with ear elastic, I made some shaped and some pleated. I found pleated ones pressed my nose down and felt uncomfortable, the shaped ones are much better. Ear elastic hurt my ears and always felt like they would ping off, so i used elastic to go round the head instead which feels much more comfortable, shorter on the bottom to fit snug around the neck. The design can be made so the inner layer is a pocket for air filter material. My hope is that if people use these, then it means the medical grade protection can be saved for the medical staff that really need it. I can't make anything in sufficient numbers to help the NHS but can help smaller local groups of people who won't get any protection offered, but are still coming into regular contact with people.
markmellors
commented
4 years ago Oh also, I am wondering whether rolls of aluminium/stainless steel wire strip for nose covering could be bought on a roll from Screwfix/tool station or other hardware store still operating as a click and collect. I'm trying to limit my online orders now as post service completely under pressure now.
I used a small piece of rolled up kitchen foil in mine. seems to work ok. slightly springier steel may be better, but I think its as good as buying aluminium strip, and easy and adjustable stiffness.
JackiePease
commented
4 years ago This article from The Guardian seems interesting re. use of DIY masks - there's a section on "Using and Taking Care of Your Mask" with guidance on when they should be used, how to take them off etc. https://www.theguardian.com/us-news/2020/apr/06/how-to-make-no-sew-face-mask-coronavirus
KayaScott
commented
4 years ago Hi Having trouble getting into github again!!
I came across this mask (part way down Olson Mask) from Cedar Point Medical facility
https://www.weneedmasks.org/sew-a-mask/
A couple of things.. they use a replaceable filter ( the hepa)
They place, but don't fix a pipe cleaner instead of the aluminium strip (this is in a few designs)
They also talk about sterilising the mask in an oven at 140 degrees F The fabric non filter part can be washed at 60 degrees.
I am now part of the Fabric District scrubs group, so focusing on this
But best of luck... kx
On Tue, 7 Apr 2020, 12:33 markmellors, notifications@github.com wrote:
Oh also, I am wondering whether rolls of aluminium/stainless steel wire strip for nose covering could be bought on a roll from Screwfix/tool station or other hardware store still operating as a click and collect. I'm trying to limit my online orders now as post service completely under pressure now.
I used a small piece of rolled up kitchen foil in mine. seems to work ok. slightly springier steel may be better, but I think its as good as buying aluminium strip, and easy and adjustable stiffness.
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/DoESLiverpool/covid19/issues/17#issuecomment-610334476, or unsubscribe https://github.com/notifications/unsubscribe-auth/AO4LVST6GYMXCH4FN3IMBVDRLMFPHANCNFSM4LVVD7GQ .
tamhamilton
commented
4 years ago Apparently 75deg C is the minimum temperature proven to kill Covid-19. Below that temperature you're relying on soap/detergent/alcohol/etc to kill it.
Polypropylene should be OK up to about 100deg C, I think. It has a melting point of 130deg C. That will definitely require some testing though (pour boiling water over it, see what happens).
This might work for the nose wires: https://www.toolstation.com/mig-welding-wire/p18355 It's not galvanised or stainless, so probably not very useful for reusable masks or sterilising.
Something like this may be better, but it really needs to be tested to find what works well: https://www.amazon.co.uk/Stainless-Steel-24AWG-0-50mm-Extra/dp/B01BFI3HJQ/ref=sr_1_2?dchild=1&keywords=0.5mm+annealed+stainless+wire&qid=1586263182&s=diy&sr=1-2
TheSmallLebowski
commented
4 years ago Thank you everyone, some really helpful suggestions there.
ajlennon
commented
4 years ago Feedback from Helpful Engineering that there's a cloth face masks project channel here worth looking at
tamhamilton
commented
4 years ago Can't sign up to their slack right now - the invite linked on their Twitter has expired... Am I missing something, or doing something wrong?
ajlennon
commented
4 years ago
It feels like most people involved in the PPE effort have concentrated on what we have been told by medical professionals should be called "eye protectors" i.e. the face visors we are designing and printing / laser cutting / etc.
I suspect this is because we don't know if we could provide a filtering face mask that would be useful to medical professionals and those in the community and we don't want to be producing useless items that are of no real benefit.
There seems to be a lot of confusion around this issue so I am hoping we can come to some science backed conclusions as to whether we can do something, or whether we should leave this alone.
There has been discussion on Twitter - I think on @realsexycyborg's threads - that a lot of 3D printed face masks are useless. A big problem seems to be they don't properly fit to the face.
More recently I read this article which is saying the the following
https://medium.com/@thejanellemj/please-join-me-in-wearing-a-mask-71e0e3f4fe4a
@AlyssaAlabassi (Surgeon) provided this link to an opensource printable mask on Twitter
https://www.futura-sciences.com/tech/breves/imprimante-3d-coronavirus-masque-n95-impression-3d-2211/#xtor%3DRSS-8
ref thread: https://twitter.com/AlyssaAlabassi/status/1243956886329843713?s=20
She also provided this link from the Lancet on use of masks
"Rational use of face masks in the COVID-19 pandemic"
https://www.thelancet.com/action/showPdf?pii=S2213-2600%2820%2930134-X