DIY UV disinfection box for N95 masks and other equipment, fight coronavirus video!
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- čas přidán 5. 09. 2024
- In this video I'll show you how to make a DIY ultraviolet disinfection and sterilization box using common materials found around the house. This can be used to disinfect used N95 masks and other items that may be contaminated with coronavirus (COVID-19), or other pathogens. The total cost of the materials for this project is less than $120. You can make a box for yourself, or you can give one to your local hospital, clinic, fire, or police department to help them out.
3D printing files (download FREE to 3D print yourself. If you want to order printed for you, you can do that as well at the link):
2 mask holder: ow.ly/tXSX50z9Afu
1 mask holder: ow.ly/n86350z8ktx
2 mask holder, set of 6: ow.ly/Ress50zm8yY
1 mask holder, set of 6: ow.ly/QN5J50zm8A7
Materials for this build (As an Amazon Associate, we earn from qualifying purchases, thanks for your support!)
UVC LAMPS!
1) 14" UV germicidal lamp (may be sold out): amzn.to/34fLTgA
2) Alternative 60W LED UV lamp w standard E26/E27 socket: amzn.to/2wi1foz
*E26/E27 light socket (needed for the 60W lamp above): amzn.to/3aKuYoY
3) Some people report success with fishtank UVC lamps (I haven't personally tried them). They are low power and you have to adjust your light-on time to compensate for the lower power. amzn.to/3eIPuc3
4) Here is another fishtank UVC lamp, also lower power but the correct UVC wavelength amzn.to/3bwZuDi
Brinks digital timer amzn.to/2UOKafv
Heavy Duty aluminum foil: amzn.to/2JGRcwb
Gorilla glue: amzn.to/3bRF0Vx
Machine screws and nuts (use #6): amzn.to/3dZNgoo
Washer set: amzn.to/3bSyE8d
Adhesive velcro-type tape: amzn.to/3c0VzhP
Hook and loop cable ties: amzn.to/2yBbq8i
Large cardboard boxes: amzn.to/3e6uxr2
Packing tape: amzn.to/2JNuFOo
White spray paint: amzn.to/34chj7C
Silver spray paint: amzn.to/2xUyMWo
Nothing in this video should be interpreted as medical advice. This isn't an FDA-approved method of sterilizing or disinfecting medical equipment. Use appropriate care when working with UV light. - Věda a technologie
I'd like to make a couple of points to address some of the comments:
1) The light source in this video, and that discussed in the research paper mentioned, are 254 nm UVC, not 454 nm. This was misspoken in the video.
2) N95 masks are intended for single use. It is only because of the critical shortage of available masks that health providers are FORCED to reuse them. Sometimes a single mask is issued for an entire week. This method may not be perfect but it is better than the alternative, which in many places is nothing.
3) Some comments say that UV does not penetrate the mask to get particles trapped inside. This may be true but even surface sanitation is helpful, as the mask surface must be touched to put on or take off the mask. Research suggests that UV works for disinfection of masks. The US CDC lists UV germicidal irradiation as one of three methods to decontaminate N95 masks during this crisis:
www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html www.ncbi.nlm.nih.gov/pubmed/29678452
4) Some comments say that UV breaks down the mask. This is true, but only with significantly higher doses than in this video. When exposed to a UV dose that is 150 to 1200 times larger than the 5 minute dose from this video, filtration efficiency decreased by 1.25% in this study. At the levels shown in the video, the effect should be negligible.
www.ncbi.nlm.nih.gov/pmc/articles/PMC4699414/
5) Some comments say the calculations of surface UV dose are imperfect. I know this and addressed it in the video. This why I chose to use a UV dose 8 times that calculated minimum -- to account for any inefficiencies with geometry, bulb irradiance, and a variety of other variables.
Thanks and be safe!
Don't expose your skin or retina to 254nm. Major risk factor for malignant melanoma !
Based on #3 and #4 why not use Ozone generator to disinfect? Just use properly, that's what I am doing.
@@fc-pl9kr that would desinfect very well. But ozone is such an strong oxidant, it will eat though the elastic bands (ozonolysis)
Embodi3D a better, recommended method to disinfect masks is 158 degrees Fahrenheit in an oven for 30 minutes , making sure the masks do not touch any metal components.
@@fc-pl9kr Unfortunately, the amount of equivalent Ozone generation methods would be long and would require a number of other ventilation methods. UVC is the best alternative, with papers (as he noted) supporting the 254nm log3 99.9% kill rates. These do not exist for Ozone.
Dr. Mike, I would like to thank you for the video you have made and for the time you have invested in doing your research and for your efforts in fighting the corona virus, saving people lives and the lives of follow healthcare personal by creatively trying to find a solution for masks scarcity. I have no technical knowledge to comment on your project but I only want to thank you for your services to humanity. I pray for you and everyone out there to be blessed beyond known measures. - Mohammad from Kuwait
use a $20 ozone gas generator which gets into all the nooks and crannies...
As a doctor fighting with the Covid 2 for us, I spread my deeply respectful for all of you, and you guy have to face the shortage of ppe, and you still make your own method to do it, respect, respect, respect !
:)
Yay Evergreen! Thank you!!
Thank you. I just ordered a UVC bulb from ebay (china). Attention buyers, there are many fake ultraviolet LED lights out there that glow like black light and do not disinfect - UVC LEDs do exist but are rare and not cheap. Really enjoyed the video, you have a lot of skills in different fields :)
Thanks so much Doc!! Dentist here, at least you guys can get N95's. We're jerry-rigging masks with P2.5 filters to try and take care of our emergency patients. This was great help!!!!
Hello! I am a dentist too ❤
me too ...
Indoor "grow tents" can be bought online. Cheaper than you think and better built than any cardboard box. Plus most have built in ducts for airflow. 4 inch duct fans move good amounts of air and cheap dryer vent hose can remove any "ozone" outside with a little planning.
Back in high school during the early 70's we were required to wear protective goggles in both wood and metal shops. After use the goggles were hung in a special cabinet which was equipped with a UVC lamp. The doors were equipped with interlock switches to prevent exposure to the light. The cabinet was also equipped with a 10 minute timer. Shop time over everyone returned goggles to cabinet where the instructor would set the timer for the full 10 minutes. This was in the USA. Fat forward to today and living in the EU I see that butcher shops and barber shops / Beuaty salons are equipped with sterilization cabinets for their knives and combs and shears. According to instructions one is to wash and dry the tools of the trade and then place them in the cabinets and hit the start switch. They are equipped with automatic timers that are preset by the factory to insure proper sterilization.
YES! I have one of those cabinets! I bought it 20 years ago, as I do light research and therapy and collect old equipment. In January, I unloaded a storage and rediscovered the light cabinet and decided to sell it, but couldn't find anyone to buy it. I asked my dentist, as they have patients wear sunglasses while they work on our teeth (1st time I've experienced that!), but they wipe down the glasses after each patient and didn't see any benefit (???) to using the light box. I wonder how they feel about my light box today? They have been closed for the past month). LOL..... In reality, since I live in Phx, Az, I simply put everything in the sun for a couple of hours -- my BIG light box! Ha ha....
Great video,
I have worked with UV lamps for many years and these are my recommendation for best result with the UV light in a box:
1- TEFLON sheets instead of the Aluminium foil.
2- Air circulation fan in the withing the box the reduce the lamp surface temperature.
3- Ozone also known to kill the virus.
Hi Jaffa, thanks for sharing this. I would like to confirm is TEFLON sheet same as reusable baking sheet? s.lazada.com.my/s.dRRQi
I built a similar sterilizer out of a Rubbermaid patio storage box with a lid. I built the timer into the unit, so it's nice & self-contained. And I included an interlock switch that disables the lamp if the lid is open, so there's no chance of accidental exposure.
I saw a CZcams video on how they tested it with a banana and electrical tape. Putting it close to the banana turned it brown, but the part covered by electrical tape didn't. Seach it on CZcams. I have a glass tube similar to the one in this video and it did turn the banana brown. I bought a photo box that has foil reflectors on the insides. I dangled the light tube inside. All I need is the racks. Good idea!
I and probably most other reasonable people thank you for information. The research, effort, $100+, recording, responding, the time as well as increasing personal time shows you mean well. If you told us you had 10 or 30 or 100 hours from prep to current there’s unfortunately still a few that can’t find some positives out of your message. Good job and I appreciate the video.
I recently made this. Very easy to assemble and affordable. Mine is from a standard 18x18x14 shipping box and has a dish rack to hold the item(s). Not as fancy nor hold as much but works for 2 or 3 items. I am eager to see research as to effectiveness of UV-C light as well. Thanks for the instructions and information.
Thanks Patrick!
Be careful of the LED based bulbs for $60 out there. They are finding them to be fake and not using LEDs in the 254nm spectrum, which means they kill nothing. Stick with legacy low pressure mercury UV-C bulbs.
exactly, spent $70 for a claimed to be uvc at 254nm, turns out to be 390 uva light. luckily seller refunded fully, kept the the light but no use of it.
@@adaptivemind How do you test for uvc vs uva or b?
mwatercress uvc burns the skin,irritates the eyes and has a sharp ozone scent after exposure to surface
@@mwatercress czcams.com/video/G_Fsp7fzNYI/video.html explains how you can measure yourself with simple lenses and ruler. very interesting vid. also i think O3 chamber would do better to sanitize fabric materials and small items. UVC light better for large surface items and rooms.
tom thumb i don’t think that method will work for a wavelength of light that your eyes cannot see and yet can damage them by looking at it...
Please be sure to turn light OFF before opening. UVC can damage skin quickly.
Thanks, Doc. I am working on my own but I tweaked your design. I used foam core board planks coated with foil tape and put into a box..
I am using an ozone generating (183 nm) bulb and I will be keeping my box outside. I did some research about O3 and found that it has been used as a disinfectant for 100 years. I figured ozone and far UV light would be a double whammy and would suffuse every surface put inside the chamber.
O3 breaks back down into O2 in about 30 minutes making it safe to open the box by then.
But I've read in an article that if you sterilize masks using a UVC lamp or autoclave it can rupture the filters, but we can use dry heat sterilizer if we want to re-use and sterilize our masks
What a difference 2 years has made. I use UVC in my house for disinfecting. The lamps are so cheap now.
Great Video. I watched it this morning and built one this lunch time. I had previously bought a UV tube but found it too dangerous even with glasses, without the enclosure you outlined. I've now used to sterilize mail, and food we bought ahead of storing it. I think I will put an interlock switch on the door for safety. Thank you.
Awesome video!! Thank you Doctor!! Not only are you a Hero working on the frontlines helping people during this pandemic ...while risking your own health and life..you also are thinking outside the box (no pun intended) ..coming up with a great solution to the shortage of face masks. I only have a few N95 work masks that I had from doing home renovations and I was wanting a way to sanitize them. I am not in the healthcare industry but I do work in a essential service and I have been trying my best to keep myself /family and others from getting sick. You are an inspiration to me! I am going to try and make this for healthcare workers in my area!
Peace and love from Canada!
Stay safe brother.
Seems much better than all the little wands that folks are selling on Facebook. Thanks for the idea!
Indoor grow boxes are pretty much ready to go for this purpose. Reflective inside, and light stays IN.
10 minutes i would suggest
Thank you so much for sharing this valuable knowledge, I already have all the items to build one like yours tomorrow, if all goes well, I will make one or two to donate to my local hospital in Chiquimula, Guatemala. For more people like you !!!!! Thanks again.
I done a similar type of box, but I used a t5 style bulb in a plastic outdoor bin that I’ve lined with Mylar
Do you have photos? Tnks! ing.martinez0417@gmail.com
I made a disinfection box for my wife’s RV. She is a nurse and is mandated to change her clothes when going off duty and only has been issued 1 n95 mask. So the box uses 1 115volt 35watt 180nm bulb that intent fully produces O3 gas to kill below the surface . It runs off a cheep inverter. Yup I’m nuts, but having insulin dependent T2 diabetes and my family’s welfare drive me to this.
Great video from a holistic point of view: from start to finish. UV exposure calculation is wrong, because it dissipates with distance: initially power, and then exponential. I purchased a box made in China for $30, inside dims 26cm x 19cm x 17 cm, 9 WATT mercury bulb. I also purchased a UVC Meter. At the bottom shelf, around 15 cm from the bulb, exposure was 28 microWatt / cm^2. At the middle shelf, around 7-8 cm from the bulb, exposure was 60 microWatt / cm^2. If I *used* your calculation, exposure would be function of the box, which is both wrong and too high. Assume mask is 10cm x 10cm, sitting on the middle shelf, and uneven surface discount of 0.25 => 60 * 10 * 10 * .25 = 1500 microWatt = 1.5 milliWatt = 0.0015 J = 1.5 milliJ. So to get 300 mJ exposure, I need 200 seconds, which is 3-4 minutes. That's not very different than yours. But per your calculations, I would need like seconds.
I have used this for about a month now.
Was noted that similar math i found to be for Sars.
It was noted that aftet 10 times using this method the mask integrity and bands decayed to beyond use.
These are disposable masks. Many are finding that the reuse of these masks does more damage then the different disinfecting processes.
Yes -- The UV breaks down the rubber in the elastic straps, and they loose elasticity. A typical N95 mask's strap will even just break after repeated UVc irradiation.
This also raises an interesting point, that I have yet to see mentioned. STOCKPILED mask (for example N95) mask have a limited Shelf life, for many reasons, but one is that the elastic strap deteriorates over time. (depending on how they are stored). Even when stored in a light sealed container, at typical room temperature, I have seen N95 mask that are 7-10 year old, have virtually no elasticity in their straps, which break as soon as they are stretched.
Well that is outstanding to know. That means our supply of masks is times 10 times more than we thought we had!
@@gsdmaxima9643 If so, could the elastic strap be replaced and make the mask useable?
what wattage, distance and duration did you use.
Research shows effectiveness at 8 feet for 15 minutes using a 40 watt Philips lamp. The testing was a few years ago and used the MARS and SARS virus.
Something to adjust for is actual power of a lamp at the 254nm wave length. If typical low pressure mercury UV C, its 30-40% of total rated bulb power.
Good
Yeah, we did something similar at our household. We purchased a wire shelving 7 feet high with multiple wire shelves, we wrapped it in mylar. We have our UVC lightbulb on a remote control timer.
Good idea! Watching this made me think you could use old appliances like toaster ovens and modify for this purpose doing what you've done with the box.
Very useful video. Thanks . This project uses UVC to effectively sterilise masks and other potential contaminated materials. I use a 16 watt Philips TUV lamp for the same purposes.
Thank you for this video; It was very informative. I plan to use it for my CPAP therapy equipment too.
If the electrical power is 30 watts then the UVC power at 254nm is about 7 watts. So increase the times by 4x. UV is strictly line-of-sight; viruses within the material will not be inactivated. Pasteurization is effective against Cov-1. 145F for 30 minutes. Ovens are readily available.
Thanks for the video! There's also the fact that the virus dies after a period of time. So combining uvc and systemic rotation of a number of masks should still be quite useful.
Exactly! There's more FEAR than sensibility in the world! The virus CANNOT live in the air without being enclosed in a water droplet, and it's only viable for hours on most material, and a few days on hard surfaces. Having 5-7 masks and wearing one/day, by the 6th or 8th day to rotate masks, the 1st mask will be virus-free. So, nothing extra is needed to disinfect it. Combining with UV sterilization is more than enough.
Make sure you let your lamp get to optimal operating temp before you start the clock 7 min or so .
I have a UVC lamp (also from Amazon) that I've been using as a final, extra step in sterilizing the back of my squad's ambulances. I'll have to build a box to use with the equipment as well. Thanks for posting and stay safe!
Good for you. Thanks for your great work as a first responder. Stay safe!
you dont need a box..just set your ppe in front of the lamp
UV is not reflected
@@johnnyllooddte3415 If it's not reflected, where does it go?
I think the box is more a way of containing it to stop it getting in your eyes, it also needs to be kept away from children and pets
I have just been using he middle rack on my convection oven preheated to 170F and bake for 30 minutes along with my mail, change, etc.
isettech are you laying them on the rack or suspending them?
You must suspend them to avoid damage to the filter medium, hopefully you are doing that. This is a far superior method to UV.
It’s going to be my weekend project. Suspended is how the Stanford study recommended it be done. I was curious to hear from someone who had actual experience. Thanks.
@@robertalonzo5725 I put them on the rack face up after a quick dunk in water as heat is most effective when in a high humidity range. The leaves the outer and middle filter layers intact, and the inner layer is not a fine filter, but a protection from facial hair, nose, etc touching the inside, so yes that is on the rack. It goes in flat face up, and damp, gets a good bake while drying.
I suspended them from wooden spoons @170 for 30 min. They look to be in good shape.
Thanks, I’ve just made my UVC sterilization box inspired by your video! Done some amendments where I used some metal shirts hangers as stands and top danglers as well as a middle net shelf! Thank you so much for the great video
Can you please share of picture of this apparatus you made with shirt hangers and top danglers? I would like to make one for my UV box as well. Thanks!
adschan1 Sure, here is my email humyac@gmail.com contact me and I’ll send you some pictures of the box I made!
Good Job! I would suggest putting in a second UVC bulb as the Watts of the bulb are not the watts of UVC irradiation the bulb emits. Look up the bulb and the amount of useful UVC coming from it will be posted by the manufacturer. Stay safe and thanks for being a solution in this grand equation.
Thanks for your time and effort to help others not only in the front line of care but also in prevention. It is clear that is not FDA approved, but if the box works and it is used with responsibility will be great in these time of crisis.
Thanks and be safe.
I read that uvc light ,will only desinfect the direct surface of the objects, in other words, need to turn the other side of mask ,in order to being hit with uvc light the whole surface of the mask
Yes UVC doesn't penetrate opaque objects. It's a surface disinfectant only.
Thank you very much for the video and your services to humanity, God Bless you and all the Medical Personal around the world.
Few facts:
-Not all UVC lights emitting ozone, only those below 200nm. 254nm is ozone safe
-UVC leds much weaker comparing to classical UVC low/high pressure tubes/globes, so one would need much longer time to achieve same result. Plus most of them emit 270-280nm, which reducing efficiency up to 60% comparing to 254nm
Thanks, Dr. Mike, for the great insights!
In the interest of speed, I ordered one of the aquarium UV lamps, since it was in stock. I also am going to try an insulated, reflective grocery carrier.
You can make the stands out of wire coat hangers. Wire. Cut up a cardboard rack and coat/wrap with foil or foil duct tape. All kinds of ways. A string with clips. Etc....
I have 2 UV-c Wands and one light that can disinfect a 600 sq ft room in 60 mins. I use the wands on things like my phone, n95 insert filter and cloth mask with 20 second passes to both sides.
Good job on the UVC box. I made a similar box and used very thin steel wire as a rack.
I used two guitar strings. The masks sit about 15cm from the uvc light leaving space of about 10cm below. It's a plastic file box from Walmart, lined with foil.
Thank you Doctor for all the information you provided. I tip my that off to you with much respect. Great video straight to the point. Keep up the good work and may God bless, guide and protect you always. Hoorah.
Nice use of your 3-D. I will line my box with foil too. Well done, Doc.
Thank you for putting in the work to do this video. I wish you good health in these crazy times!
Thank you for this project. I had this idea in my mind for long but just struggling the power of the uv lamp and the distance from the light source. Your calculation is perfectly make sense and hope I have a lab to test the result from 38 sec to 5 mins exposure time. Thank you!
Assuming the Aluminum foil is perfectly reflective, the area over which the uv is distributed is the absorbing area of the masks, not the internal area of the box. No energy is absorbed by the foil (ideally) so it’s area is irrelevant.
Warning! A 30 Watts lamp will *not* output 30W of light/UVC. Efficiency is more in the 20-30% region, i.e. a 30W lamp will output about 6-9W of UVC max. Second, don't underestimate the effect of shading &c! It's easy to lose 90+% of the initial intensity w/o really noticing the actually huge difference (human eyes sense brightness more logarithmic rather than linear). Third, as others have noted, UVC does hardly penetrate most materials.
I strongly recommend using ozone instead. A similar disinfection box can be built for about $30-50, the ozone easily penetrates fabrics and has a half life of about 12h in dry air, so flood the box for a couple of minutes, turn off the ozone generator, then let the box and content rest over night. This can, is, and probably should, of course, be combined with UVC pre- or post-treatment to maximize the effect.
Ciao Dr.Mike, a very useful project. I made a similar box and I was looking for an explanation about exposure times, and I found it. Thanks. In your calculations you use the electrical wattage of the lamp. Maybe it would be better to use the UVC radiated power, generally about 20-30% of the nominal wattage. In my box I will put, as soon as it arrives, a little ozone machine to combinate the surface sterilization by UVC rays with a deeper sterilization by ozone gas. Ciao
Wow, this is indeed very helpful Doc...Great job and Stay safe to you, your family and fellow frontliners!
Dr Mike, first of all I wanted to thank you for all the sacrifices that you, the health care providers, are doing every day to try to control this pandemic. No words or actions could recompense you enough for what you guys are doing for us . I just have a question, isn't more effective to dunk or spray the masks in a solution of peroxide hydrogen and then just hang and let it dry? By this way, the peroxide could go trough the fiber of the mask, deeply decontaminating it. Or submerge the masks in a solution of sodium hypochlorite (Clorox) and water for like 30 minutes and then rinsing it nicely? Please share your thoughts about this. One more time, thank you and stay well!
Very informative video, Thanks! Alternatively, You can make stands or racks using shirts hangers.
Great tip! Thank you!
Here’s a good idea on how to use hangers
czcams.com/video/vcyF0NCcmBA/video.html
Nice video. Some test results using a dosimeter card or reader would be great to see how effective the bulb actually is
Or you can buy a UV sterilizer for 100 -180 dollars on Amazon depending if you want the towel warm combo. Barbers and some salons use them to sterilize their equipment but they have a 30 to 40 minute protocol for total sterilization.
I made a similar box from an old cooling box, foiled the inside and using a 11Watt UV-C light bulb. Hase a phisical switch and also a wifi smart switch wich is set to 6 minutes count down. Also made a room desinfector that is on a stand and has 2x11W UV-C on it it can desinfect a room in about 10-30 minutes. Depending on the size of the room but theoretically if you let it go for an hour it can desinfect a large room also. Note that just the surfaces that the light touches! You need to move the lamp to different places to have the wholl room done. Usually I'm using it to desinfect groceries and stuff after a haul in. And I did an Ozone box also for gloves, shoes, amazon packages and bags to be desinfected. The Ozone generator can also clean a car or a room, you just need to be carefull Ozone is also harmfull for living things Viruses included fortunetly.
Use a $20 ozone gas generator from ebay which gets into all the nooks and crannies...plug hose into box. very quick
Thank you for sharing your project. Thank you for all the time and creativity you invest in this. My greatings from Florida
No. Dip them in alcohol. UVC doesn't penetrate at all into a surface.
First of all, a great video and an excellent job done. I have some doubts in my mind. I think that your lamp is rated at 24V and draws 1.1A according to the product brochure which means a rated power of 26.4W but that may not mean that it emits UV light of 26.4W. The Power of actual UV light emitted is usually less. You might want to have a look at what is the actual UVC radiant flux which can be obtained from this lamp and then calculate your duration of exposure.
From my reading of UVC lamp specs, a typical 40W UVC tube only produces about 6W of actual UVC light
@@gsdmaxima9643 Exactly!. Moreover, the UV power emitted is at the source, thus the decrease in the intensity of UV light as the distance from the source increases also must be taken into account.
No calculations should suffice - you have to do some swabs and see what grows. That's the proof you need.
@@gtjhuli bhai. Then have you made something like this in India? Any details? Don't want to purchase b those costly 11k uv ovens. Which Indian uvc lamp should i buy for my diy project?
I think that place the masks in a oven or passing the iron clothes on it, should also work well.
If you iron an N95 mask you will almost certainly ruin it. An oven is okay, but you need precise temperature control. A little too hot, and the mask won't filter properly anymore, not hot enough and the virus will survive.
Superb project. Please include the UV Eye Glass protection demo for extra safety. Or can be enhanced to put an auto switch off when opening the UV box. Great work Dr. Thank you.
Hey thank you. I am a stage 4 cancer patient works in healthcare. i am taking extreme precautions. they arent giving us ppe. i had to purchase my own. thank you for the information. I am interested in the Racks please. Chemos tomorrow so I hope and pray that when my light arrives I will have the box partically built.
My hospital also doesn't give us enough PPE. We have to reuse. I bought my own goggles. You can download and 3D print the files for the mask racks for free. If you want to order them 3D printed for you, that is also an option. Here's the link. Stay safe. ow.ly/tXSX50z9Afu
Use a $20 ozone gas generator from ebay which gets into all the nooks and crannies...
I just had a very good idea: put a mask into a zip-lock bag which can take 75 to 85 degrees C (167 to 185 Fahrenheit) . Heat 5L water to 85 degrees C and pour it into a plastic bucket into a tub and then submerge the zip-lock bag in the water under something to weigh it down for at least 30 minutes. Monitor temperature every 10 minutes or so and add more hot water so it stays between 75 and 85 degrees Celsius. The more water is initially heated and added to the bucket, the more constant the temperature will stay (hence less monitoring required).
Material decay can be an issue with UV. Also light may not affect anything that is shadowed like inner layers or anything in between layers. But as long as material can take it, it is a great way to sterilize the surface. I'd assume there is not enough ozone to sterilize the inside.
A lot better method than doing nothing! Some UV is probably reflected or transmitted to some of the first layers.
Yeah this works but study shows that the UV C light after each use on the mask will deplete the filter efficiency over time rendering it useless.
Another way to go is making an Ozone box. Ozone also works to clean a room or inside a vehicle. Read up on it before using it.
Very informative. Thank you. Ive been wondering why we need the foil.. That answers my question
Thanks for this. Before I saw your video, I made one very similar. My box was ShopVac, not Rigid :-) Also, I used 3M spray adhesive to bond the foil to the inside. Although I don't have a way to measure the UV output of the bulb I'm using, for the strong ozone odor it produces, I'm pretty sure it's putting out plenty.
That's amazingly clever !!!!! 👍👍. Congratulations for the initiative !! Thank you for sharing your knowledge.
Maybe the funny smell you mention could be ozone. I have done a similar box months ago with a T5 with 8W 254nm with ozone generation, and attach the lamp to a IoT socket that I control with the samrtphone and Alexa. Let the lamp on 15 minutes and it smell like pool chlorine, it's ozone and it's very helpful to sterilice where UVC light can't reach.
GRACIAS Y SALUDOS DESDE ZACATECAS MÉXICO.
Thanks Doc. I'm using my wifes CPAP UV cleaner for our masks now. You rock!
Thanks sir, 🙏
From India, for this technical information!
Very thans
LED UV bulbs are less ideal as they are in the UVB range. Best to use the UVC bulb as in the video at 254 nm which is close to the optimal UV wavelength for sanitization . It is difficult to kill all the virus in the polypropylene filtration layer as it is partially covered by the outer layer of the mask. Some of the UVC is blocked by the outer layer. UVC can also potentially damage the polypropylene but it would take many exposures to do that, so reusing the masks 3 times is a safe bet. Definitely I would highly suggest additional heat drying the masks at 70-100C for 30 mins as the viral membrane is sensitive to heat.
God bless you. You really took pain for kindness. INDIA
Just note that you should not use PLA to print the mask holder, PLA breaks down with UV light
Thx for the math part. I feel really dumb. Helped me calculate my own box.
We clean ours with Virex Plus, rinse and let it air dry. After it air dry, it goes into our UV box. I heard Hydrogen Peroxide and hot water soak for the mask is good too.
UV-C light will not even penetrate the atmosphere. So it likely won't penetrate to the middle layer of the mask. The box would be effective for cleaning goggles, phones and anything that the light can reach. As long as the surface is clean.
The lamp's output decisively is dependent to it's working conditions. "Overheating" in terms of "covering the lamp by a box to protect yourself from getting irradiated" will cause a decisive output reduction, as UV lamps (low pressure mercury vapor discharge lamps) are very temperature sensitive. An ambient air temperature difference of just 1°C to 5 °C will lead to an UV output variation of up to 15% Temperature varies from 19 to 24°C
UVC lamps put out very little heat, so I don't think overheating would be an issue.
Great job .. But I would use 2 uv lamp elements diagonaly one top one buttom .. But what u ve done is great
well done.. WASH EVERYTHING BEFORE AND AFTER UV use
Please explain yourself.
I've read that there is NO residue from UV or ozone exposure.
Great video. Thumbs up. But a few comments:
1) The UVC won't penetrate the surface layer of the mask, so the inner layers of the mask won't be sterilized by the UVC.
2) All UVC lights generate ozone. It's unavoidable. The short wavelength is perfect for splitting oxygen atoms. If your lamp isn't generating ozone, it's not putting out much UVC. You can get much cheaper, incredibly dangerous UVC lamps from China, where they don't worry about safety issues.
3) The power given for a lamp is the power taken from the plug. A lot of the energy is turned into heat or radiation at non UVC frequencies. At best, you are getting a spectrum with a big hump in the UVC frequency range. So you should probably assume that a 30 Watt UVC lamp is putting out no more than 15 Watts at UVC (but if it was, you would have a strong ozone smell in the box).
4) Significant ozone generation might be a good thing because unlike the UVC, it will penetrate into the masks. Unfortunately this would make the box unsuitable for use in a room that is not well ventilated.
5) I think these projects are great, but I always remember the old joke: God must love stupid people because he made so many of them... Unfortunately, even with all your warnings, some people will hurt themselves with the UVC lamp.
Finally, I think this whole situation is very sad. My engineering company uses N95 masks to keep our employees safe from resin vapors during construction of PCB (Printed Circuit Boards). We use units that don't have a valve, but that's actually better for the current situation where you want the mask to keep other people from getting sick. These masks went for about 50 cents apiece before the coronavirus showed up so we had a few thousand to provide to our employees. It's surprising that hospitals and doctors didn't have a stash of them as well. I guess they will in the future...
Cool. Didnt know aluminun foil is ok. I thought i really needed roof insulators
I'm very skeptical of the aluminum reflecting UVC in a wavelength that is effective at sterilization. You need a very tight bandwidth for the germicidal properties of the UVC to be effective. Yes, you might be reflecting light in the UV spectrum, but its more likely to be lower energy light, such as UVB or A, if at all.
Please remember the inverse square law, you definitely need a UVC light meter to ensure the actual irradience the bulb is giving you. And that measurement should be taken at your darkest point. Also, look up N95 Filtering Facepiece Respirator
Ultraviolet Germicidal Irradiation (UVGI)
Process for Decontamination and Reuse from Nebraska Medicine, this paper is great to get a better result.
Thanks for the comment. I've read the Nebraska paper. The inverse square law doesn't work because the interior of the box is reflective (aluminum is 90% reflective at that wavelength) and energy is bounced around inside until it hits something absorptive , and the only thing that would be are the masks and holders. So, absorbed energy is higher than the inverse square law would predict.
@@Embodi3D Thank you for the reply! That is the reason for the meter, there is definitely multipath going on as you described. The other factor is the rating of the bulb, it may be listed as 30W, but that may not be its output at 254nm. Normally it is much lower unless the rating specifically lists the rating as being at 254mn.
I am given to understand that the UV can wreak havoc with the electrostatic charge on the filter material. This charge is crucial to capturing particulates on which virus can reside. I'm just passing this along, I am not in a position to validate this assertion...
You might wanna look into mylar sheet instead of aluminum foil, supposed to be more reflective
I don't have a 3d printer, the next best thing to do woulbd be to have glass shelves to put the mask onto which are seethrough, I don't know if acrylic lets uvc light through though.
I would put the light down vertically from the top, center. All masks could be arranged in a circle around the light, evenly distributing to all masks...JMO
Nice' i made a same box, using a small PVC storage box and glue a foil inside
to disinfection my mask, phone and wallet etc.
Thank you very much for sharing important information. Can i use this UVC to sterilize grocery specially fruits and vegetables? If yes, any precautions or exceptions.
I don't see why not. Fruits and vegetables sit in the sun and are exposed to UV with no ill effects.
Embodi3D thank you!!
If you have SUNLIGHT, put everything in the SUN/UV....as he said, the fruit grew in the sun. I have a UVC cabinet, but I simply throw everything in the sun and turn every so often.
@@kazart4772 most uvc does not pass our outter layer of atmosphere. not enough intensity in sunlight to kill corona virus.
Not true.
Any design really needs to be verified with a UVC meter in multiple locations of the box before you know the dosage actually hitting any given side of the mask.
Great video Doc. And definitely better to do something than nothing. Perhaps theres a virology post-grad willing to help test the fabric of a mask used in a known covid+ case?
Another concern is if the methods sterilise these masks compromises it filtration capacity. N95s are meant to have an electrostatic ability to trap particles. It would be good to know if this is altered under UVC ? I expect this could also be easily investigated with the assistance of a university physics department. May be a great way for virology and physics academics can help doctors out. Manufacturers could easily do this for us but I guess they would rather we go without any protection than do tests that validate a safe means of sterilsation that could potentially hurt the bottom line of selling more units later on.
thank you for this video to you !!!!! One of the best recent videos on youtube during the coronavirus pandemic !!!! ALL THE BEST AND STAY SAFE :)
Just wonder if anyone out there ever did experiment using microwave oven to sanitize any masks ? I used the electric oven in my kitchen. I preheat it to 200 deg F for 5 minutes. I put a metal box with lid on top in the oven and let it remain inside for 30 minutes. Inside my metal box I put a cloth like a mattress for my dirty masks that way the masks are insulated from direct contact with the box walls. This is my way of sanitize my masks especially my n95 masks. I live in Phoenix. The temperature here between July and August can pass 110 in the afternoon. I sometimes left my used n95 mask on the dashboard inside my car for hours. The temp inside the car can reach 170 easily. I can not prove my methods but I feel comfortable of re using the masks again after 150 to 200 deg F sanitizing treatment from 30 minutes to 5 hours depending on level of heat.
I think an ozone generator would sanitize even better than UVC. (Just use it in a sealed room or closet so as to protect humans and pets).