Hilltrek masks

[Monk]

Interesting comments on the Hilltrek masks...I would have thought Ventile would be a good choice...
Has anyone here considered using different types of Ventile for a face mask...a main outer layer but with a pocket cut to hold a thicker grade of Ventile to act as a filter?

I agree the cut of a mask is important. There's an American site frontlinemasks.com that has a free mask pattern and YouTube videos developed by the former owner of Beyondclothing. Scott? His mask has a catenary cut design that has a better seal around the face? Also a U.S. company called FirstSpear has made a mask add on...an interesting piece of plastic like a small ruler with cut outs that the wearer uses at the back of their head to hold the mask cords more securely. Interesting ideas.

Any knowledgeable people like to comment on these ideas?

 

[The puffin squire]

One thing to bare in mind is the masks are not supposed to protect the wearer they are to stop the spread of droplets. To wear a mask for your self protection you'd really need to wear a filter fitted mask.

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[Oliver G]

I've just taken delivery of two large masks from Hilltrek, excellent service and they feel pretty good to wear, the only thing I've found is that they ride up a little when I look down so I might stitch a couple of washers on the bottom to weigh them down.

I have found though that when folded into thirds two are about the same size as the ubiquitous altoid tin, so if you have a handy little belt pouch for your tinder box it's a nice place to keep the masks so that they do not get scrunched up in your pocket.

 

[Forest fella]

My mum's been making loads for family and friends / neighbours / passers by, And I brought aload of Pipe Cleaner's for the Nose wire/rest.
She's been less bored than me. Bless Her

 

[TLM]

Been doing some reading on filtration. First it seems that filtering droplets/water aerosol and dry particles require a different filtration medium. For water it should be as strongly hydrophilic as possible and for dust it mostly does not matter. Also the filtration medium should have as much surface area as possible without it being brittle.

I am not certain but I think tightly woven cotton might not be the best material though one of the cheapest.

 

[Oliver G]

Been doing some reading on filtration. First it seems that filtering droplets/water aerosol and dry particles require a different filtration medium. For water it should be as strongly hydrophilic as possible and for dust it mostly does not matter. Also the filtration medium should have as much surface area as possible without it being brittle.

I am not certain but I think tightly woven cotton might not be the best material though one of the cheapest.

A good grounding would be looking at the filtration requirements for compressed air in industries, BACS and Atlas Copco have some really good resources.

I used to work in the pharmaceutical industry and it was fascinating looking at getting the air from the outside world, filtering it so it could be used in manufacturing and then exhausting the air after it had picked up all sorts of nasty chemicals.

I think for the purpose of a face covering it just has to impede the droplets rather than filter them out. If I wanted to filter the air I was breathing in I'd grab my old S10 respirator though strangely enough I've never had a respirator that filters the air going out so far the most effective thing I've worn to prevent me infecting other people has been just a face covering.

 

[TLM]

I think for the purpose of a face covering it just has to impede the droplets rather than filter them out.

I think that absorbing the droplet water into the filter is a really effective way of stopping them going anywhere.

 

[Oliver G]

I think that absorbing the droplet water into the filter is a really effective way of stopping them going anywhere.

I agree if all the particles can be absorbed into the mask that would be the best way but I think there are certain practicalities that we have to live with, for example I've never been able to get a covering to properly seal around my nose and I also have a beard, both of these are routes that vapour could get through. I don't think we will be able to say that the general public will be able to stop vapour release from coverings.

In the case of droplets adsorption / absorption is great but how do do we measure saturation and what happens when the media is saturated? If we can impede the droplets they may lose their momentum and drop to the deck within 1 meter.

It would be great to have access to my old university resources and do some proper research into best materials vs water droplets and vapour, I'm sure some clever bunny will come up with a material which offers the best balance between efficacy and cost effectiveness.

 

[Duggie Bravo]

I did read a study on material for home made masks, which looked at various types of materials in the home and then scored them.
Not surprisingly the ones that scored best on filtration scored worse on breathability.
Essentially though triple layer cake out tops there was no real benefit going to quadruple.
A quick google shows that there are now lots of articles.


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[TLM]

In case of droplets just slowing them down will work as the definition of a droplet is that it drops. In case of aerosols not so, slowing them down would just localize them before air currents spread them anyway.

I don't think any soft arrangement for a filter mask would be very effective, better than nothing but not really good. A silicone rubber frame and disposable replacement filters would be the traditional "good" way, it probably would be possible to design a washable filter element.

 

[Nice65]

A mask will prevent or reduce droplets from the wearer being directed at others, it will also protect against droplets landing directly into the wearers mouth, and surrounding area, and nasal mucous membranes.

It‘d be handy if everyone was already doing this and not discussing the best mask etc while not wearing any form of face covering or waiting until the 24th July 2020 when we have to. Is the 24th a sort of ‘switch over’ date when the virus suddenly becomes more infectious?

 

[TLM]

If the outgoing speed of droplets is slowed down enough it does not matter where they are going. To do that and catch the incoming ones there has to be enough interaction between the air and the filtration material.

 

[Nice65]

Chat as long as you want, wear a face covering while you’re doing it. I’m not interested in the bloody science of it, wherever infection risk needs to be reduced you will find people wearing masks and face coverings whether it’s the dentist or the surgeon. It’s so commonplace and easily understood I’d be shocked if I was at the dentists or under the knife if the person didn’t have a face covering.

 

[TLM]

I wonder if there is hard data on how effective they really are or if "we" are just assuming they are useful.

 

[Broch]

Chat as long as you want, wear a face covering while you’re doing it. I’m not interested in the bloody science of it, wherever infection risk needs to be reduced you will find people wearing masks and face coverings whether it’s the dentist or the surgeon. It’s so commonplace and easily understood I’d be shocked if I was at the dentists or under the knife if the person didn’t have a face covering.

I disagree, with respect, it's not easily understood at all. There is a huge difference between medical grade FFP3 or even FFP2 masks and a piece of cloth around your face. It is hard to breath in FFP2 masks without valves in and your dentist only has it on for the ten minutes he/she is dealing with you, but anything less will not actually stop viral infection. If the piece of cloth or multiple layers of cloth around your face are easy to breath through they are probably next to useless.

If it makes people feel confident enough to go out and get the economy going again I'm all for it (that is what this is all about isn't it?).

 

[Paul_B]

Forget it nice 65, get two nerds together and this pseudo science is what you get!!

Truth of the matter there's been plenty of discussions on mask materials on this forum and links to actual testing of many different types of materials. Including the excellent Cambridge laboratories studies from 2013 IIRC and recent additions. The Cambridge study used actual virus at the smallest and largest virus size range and measured what gets through each type of face covering material. You can speculate all you like but actual testing is out there and easily searched for.

If course if you're only talking about it and not using anything because it's not the best possible design or material then you're pretty much an idiot IMHO. We should have been wearing them for months by now. I'm guilty of being a late convert. I've been wearing masks in shops for a few weeks now, before the was talk about an announcement on making it compulsory in shops.

It's surprising to see how few wear them. Also who is wearing them. Early days I saw mostly older people. Now there's more elderly not wearing them. I see more and more wearing them in their twenties in supermarkets. I'm also pleased when I see someone in the 18-25 age group wearing them, walking past an old woman without. Also hearing conversations between family groups who after seeing me wearing my mask saying that they must start wearing them and the mother saying a box of 50 were on order. Disposable not reusable but you can't get everything right with people can you? It makes me happy that possibly my mask wearing could get others moving forward on their mask wearing ahead of the future date of compulsion.

Basically N65 has it right. Just wear something now!!! You can always find the mythical best solution later.

 

[Paul_B]

Ok have you read the test data from Cambridge? Plus other sources too. Actual filtration rate of viral particles at two different particle sizes. Also breathability too. There's even research that includes information on airflow escaping with different designs of homemade masks. Yes it's not 100% but there are options that are still a lot better than nothing. At the end of the day it's about risk reduction. If it only reduces viral particles by 70% then you could possibly cough though it into someone's face and they would not get enough viral load to catch it! If course that's just as gross picture I'm m painting to emphasise the ideas behind face coverings. I'm not saying those figures are accurate just making a point.

It's more than just making you feel safe enough to get the economy moving. It's about a little bit extra you can be doing that if everyone did it too then it could help. Of course other actions are more effective but that doesn't mean less effective actions are just a confidence thing. Looking at it in terms of absolute filtration or prevention of the virus escaping is irrelevant it's about reduction of viral particles not elimination of all particles.

 

[Broch]

Please don't be insulting when we are having a conversation. Yes I have read and understood a great deal of published material on this and it is still ambiguous. Other research has been less supportive of the use of face masks because it is likely to develop an unfounded level of confidence when other measures are considered more effective - for example (but just one of many):

Dr Simon Kolstoe, senior lecturer in evidence-based healthcare and university ethics adviser at the University of Portsmouth said: “I don’t think it does any particular harm to wear, them I don’t think it does any particular good to wear them – and as a consequence you are going to get people jumping on either side of the bandwagon. [If there was evidence showing cloth masks] make a massive difference, then we wouldn’t be having this argument.”

I reiterate, if they are any good they are difficult to breath through - therefor you will get the people that are most likely to be carrying the infection (the ones having difficulty breathing) taking them off. They should be at home self-isolating but instead they've been told it's safe to go out if you wear a mask.

 

[Stew]

Personally I think the problem is that as a society we have largely become mouth breathers where we should be making an effort to return to being nose breathers.

 

[TLM]

Last time (some weeks ago) I read about it they still did not know what is the main route of spreading, droplets, aerosol, contact. loose virus? Still somebody is recommending something, based on what.

I agree that if even a simple mask helps some, it should be used. But do we know? Do we guess? Some authority says?

Maybe we still should concentrate on washing hands or sanitizing public toilets? As I stated earlier all the hand washing has had a positive effect on other infectious deceases here. Can't be bad.