Mic sterilizing with UV-C LEDs

Hi all

I've been asked by a few local studios about this matter, one of them even asked me to quote a small cabinet with space up to 8 mics. I think the antipop will be more exposed to bacteria anyway, but, you know, clients....

Looking in the web I can find small boxes with few LEDs to clean smartphones, hairdressing accessories and such, but I have no idea if this work or not.

Also I've been reading about the danger of exposing skin or eyes at it so I'm not much into building something evolving this without being sure what I'm doing. I also see there are ready to buy UVC bulbs.

Is it actually that dangerous? Does it really work?

Apparently it does work, but the last paragraph in this article may be a reason not to...

https://www.powerelectronictips.com/killing-covid-19-with-uv-c-leds/

dirtyhanfri said:

Is it actually that dangerous? Does it really work?

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Most national health agencies and the WHO confirm the adequacy of UV-C for sterilization of bacteria and viruses, but also caution to their nocivity to the skin, and the possible emission of ozone.
There are not many reviews of affordable UV-C sterilizers, which does not mean anything regarding their performance, it's just a case of the general public not being capable of proper assessment.
It seems to me their results are essentially psychological. I would tend to put them in the same category as ultrasound-based rodent or mosquito repellents. 
IMO.

abbey road d enfer said:

It seems to me their results are essentially psychological. I would tend to put them in the same category as ultrasound-based rodent or mosquito repellents. 
IMO.

Click to expand...

Well, that's my impression too., but there's a ton of money spent on psychological issues right now.

Walrus said:

Apparently it does work, but the last paragraph in this article may be a reason not to...

Click to expand...

Thanks for the article, very interesting.

I was aware of it, so I asked a friend who works in a big pharmaceutic company. He told me they use UVC chambers for everything including measuring equipment (even pressure sensor devices, which looks similar to mics) before getting into certain rooms. He even assured me the cleaning crew cleans it with UVC lights on...

I think I'll skip this one.

The ultrathin plastic membran might be especially vulnerable to the effects of UV light. I wouldn't do it.

I think it should suffice to clean the mic cage with a cloth lightly soaked in isopropyl alcohol.

There are a lot of fake "UVc" products on the market right now, cashing in on the situation.

dirtyhanfri said:

Hi all

I've been asked by a few local studios about this matter, one of them even asked me to quote a small cabinet with space up to 8 mics. I think the antipop will be more exposed to bacteria anyway, but, you know, clients....

Looking in the web I can find small boxes with few LEDs to clean smartphones, hairdressing accessories and such, but I have no idea if this work or not.

Also I've been reading about the danger of exposing skin or eyes at it so I'm not much into building something evolving this without being sure what I'm doing. I also see there are ready to buy UVC bulbs.

Is it actually that dangerous? Does it really work?

Click to expand...

UVc is a specific wavelength UV light (around 250um). This is effective at killing tiny microbes, but is also harmful to humans. I shared this anecdote multiple times but in Russia where they were using UVc lamps overnight to disinfect a school classroom, the teacher forgot to turn off the UVc lamps one morning and children suffered eye damage.

This is a mature technology used to disinfect hospital rooms (when no humans are present) and some devices to disinfect medical tools.

There are probably numerous scammers using low power UV LEDs, like used to cure fingernail epoxy...  Another widely used disinfecting technology is misting hydrogen peroxide.

I use some low power (6W) UVc lamps around the house to disinfect beer making equipment.  Don't stare into the sun or UVc lamps.  :

A lower tech way to deal with mics is to just leave them in a drawer for two weeks?  Replacing anti-pop/wind noise filters, or soaking them in bleach would be fast, and might dissolve the foam. I wouldn't expect UVc light to damage mics but maybe ask the manufacturers.

JR

be careful with those ones... you will get fake disinfection impression vs c19 virus, even lighter viruses!
also, DO NOT TRUST  any DATA and  DIY UNITS buzzing around on internet,  a lot of idiots made some things up...
also, some data from scientific labs/organizations has some typos on units/measurments/results....
i dont know if on purpose or not.... 
whatever info you read, make sure you can verify those information/data your self  with your own tests with proper calibrated equipment! (dont use arduino based diy staff)
UVC is very dangerous;
if u decide to mess with UVC :
make sure u are covered all around with thick layers, wear glasses, and face shield, gloves etc etc
and measure how much leaking etc remotely, before feeling comfortable!

EDIT: some typos +
make sure you get OZONE FREE lamps if plan to use in small enclosure... also, make sure you know what you are doing before getting involved with UVC....

Walrus said:

Apparently it does work, but the last paragraph in this article may be a reason not to...

https://www.powerelectronictips.com/killing-covid-19-with-uv-c-leds/

Click to expand...

that article is full of false information.
how long UVC light at 254 nm would take to kill c19 virus is depends on your distance between CFL and the source that needs to be disinfected. and you need to calculate and measure your intensity.  (measure : because UVC CFL s are not giving out even light through out its length)

254 nm 40W UVC CFL at couple of  inch will kill c19 in less than a min.  "after 3 to 5 min warm up/stabilization time at first start from cold " after warm up, it will just wipe up anything in front!

if u have 10mW/cm2 intensity of 254nm UVC  for 60 sec will result in 0.6J/cm2 : this what u need to kill c19 : nothing less!
led lights doesnt kill any virus! at least commercially available ones! they may be good for cleaning up some bacteria, but thats about it. if you google u might come up with 254 UVC led light adds.... none are true. all fake adds!

living sounds said:

I think it should suffice to clean the mic cage with a cloth lightly soaked in isopropyl alcohol.

Click to expand...

Agree

Scodiddly said:

There are a lot of fake "UVc" products on the market right now, cashing in on the situation.

Click to expand...

JohnRoberts said:

There are probably numerous scammers using low power UV LEDs, like used to cure fingernail epoxy...  Another widely used disinfecting technology is misting hydrogen peroxide.

Click to expand...

That's my impression too, I don't want to become one of them by selling something I'm not sure of.

kambo said:

UVC is very dangerous;
if u decide to mess with UVC :
make sure u are covered all around with thick layers, wear glasses, and face shield, gloves etc etc
and measure how much leaking etc remotely, before feeling comfortable!

EDIT: some typos +
make sure you get OZONE FREE lamps if plan to use in small enclosure... also, make sure you know what you are doing before getting involved with UVC....

Click to expand...

Thanks for the advice and safety guidelines, but I won't mess with it, I don't feel comfortable about it, the more I read, the more doubts I have, both regarding safety and usefulness.

Interestingly, just yesterday I had a visit from a Representative of my HVAC company to discuss installation of UV-C units inside the duct work of my heating/cooling systems for purpose of cleansing the air circulating throughout the studio and, separately, the home. I had noticed they offered such a unit when I went to their website a few weeks ago to check current oil prices. Since their unit is installed and contained within the ductwork, no light is emitted as to be a danger to skin or eyes. This danger is similar to that of exposure in tanning salon beds. Based upon what we discussed, and what I have read elsewhere, I am 99% certain that I will have these installed as budget allows. One thing to consider with this system is that the bulbs have to be changed on a yearly basis, which they would do as part of the seasonal HVAC tuneup.

Kambo's right...

In water treatment, UV lamps are very high intensity and power. Usually 500W or so. That doesn't mean you can't find 40W units. But these are not suited if you want to get rid of all microbial particles. They have some use in hydro- and aquaculture, if you need to keep the level of bacteria a bit down.

Virii are very unreliable when it comes to testing. I think it depends on the way test virii are grown.

Steamed Beech wood used to be standard in kitchens. It kills everything on it's surface in minutes. There has been some research, but no conclusion as to why that happens. And since there is no scientific consensus, the EU doesn't allow the use of Beech wood in kitchens. Inox or EPDM plastic is what's used these days. Yet, on these materials, microbial life can take up to days to die. They are, however, easy to clean. AFAIK there's not much research about virii in the kitchen.

So don't assume.

I would be very surprised if any real UV-C led cobs out there has enough power to kill virii in a short term. And you don't need long-term as the average virus dies off in hours in the open. The reason is that most viral infection sources come in tiny droplets (sneezing, coughing, speaking...). Depending on the weather, they die off slower or faster. Humid weather is an advantage for the virus as it needs the water in the tiny droplet.

living sounds said:

I think it should suffice to clean the mic cage with a cloth lightly soaked in isopropyl alcohol.

Click to expand...

As much as I wouldn't hesitate to do it with dynamicn ribbon and electret mics, I would be cautious for "true" condenser mics (external bias). A tiny drop of liquid can agglomerate dust, which makes it a potential humidity absorbent, that turns in a partial short, which results in noise and level loss. I know it's a lot of if's, but caution is the rule with static mics.

Don't all the data point to infection occurring after inhaling  respiratory droplets (and/or touching one's face/soft tissue after physical contact with the virii)? Let's assume an infected individual sings into a microphone. Let's say their respiratory droplets saturate the microphone (for sake of discussion, let's say it's a U87). The droplets would adhere to the body of the microphone, the head basket, the capsule itself, capsule holder, etc...

Now let's say someone else (uninfected) sings into the same microphone an hour later. It seems there would only be two possible ways they could become infected - they could touch the body/head basket with their hands and then touch their face/soft tissue, or they could put their mouth on the head basket. I can't imagine that the droplets deposited on the capsule/capsule holder, etc would spontaneously "jump" from those surfaces into the lungs of the singer (unless they were sucking on the head basket).

Shouldn't we be fine if we just wipe down the external surface of the microphone with an alcohol/disinfectant wipe? Why should we be concerned about the internals?

Spiritworks said:

This danger is similar to that of exposure in tanning salon beds. Based upon what we discussed, and what I have read elsewhere, I am 99% certain that I will have these installed as budget allows.

Click to expand...

Not to quibble and while UVc is a component of sunlight, tanning beds typically use UVa and UVb longer wavelengths.

UVc from the sun is generally trapped by the ozone layer..... If we didn't close that hole in the ozone layer it might have prevented covid (joking) but likely more skin cancer (not joking).

JR

kambo said:

that article is full of false information.
how long UVC light at 254 nm would take to kill c19 virus is depends on your distance between CFL and the source that needs to be disinfected. and you need to calculate and measure your intensity.  (measure : because UVC CFL s are not giving out even light through out its length)

254 nm 40W UVC CFL at couple of  inch will kill c19 in less than a min.  "after 3 to 5 min warm up/stabilization time at first start from cold " after warm up, it will just wipe up anything in front!

if u have 10mW/cm2 intensity of 254nm UVC  for 60 sec will result in 0.6J/cm2 : this what u need to kill c19 : nothing less!
led lights doesnt kill any virus! at least commercially available ones! they may be good for cleaning up some bacteria, but thats about it. if you google u might come up with 254 UVC led light adds.... none are true. all fake adds!

Click to expand...

CFL UVc bulbs are easier to make more power than standard fluorescents, but like all CFLs be careful about over heating them. I cooked one 15W CFL UVc lamp because I left it inside a beer fermenter too long while disinfecting it... my 6W UVc fluorescents  never failed like that.

JR

JohnRoberts said:

CFL UVc bulbs are easier to make more power than standard fluorescents, but like all CFLs be careful about over heating them. I cooked one 15W CFL UVc lamp because I left it inside a beer fermenter too long while disinfecting it... my 6W UVc fluorescents  never failed like that.

JR

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what kind a 15w lamp did u cooked. was it in a vented or unvented sealed space!

i have been doing intense testings with this below kind lamps, only problem i have noticed so far, if u over heat them due no vent, their UVC output drops about 15%-20% . but never left them unvented over an hour in a unvented/sealed enclosure!
my units doesnt need to work over 10 min at a time, so 1 hour tests good enough for me! but i should do burn test, incase
some of the sensors fails!

https://www.osram.com/ecat/PURITEC%20HNS%20Compact%20L%20Lamps-PURITEC%20HNS%20Germicidal%20Lamps-Ultraviolet%20Lamps-Specialty%20Discharge%20Lamps-Entertainment%20&%20Industry/com/en/GPS01_3049001/PP_EUROPE_Europe_eCat/

kambo said:

what kind a 15w lamp did u cooked. was it in a vented or unvented sealed space!

Click to expand...

An inverted 5 gallon beer fermenter, not sealed but no convection flowing.  I have had normal CFL bulb fail inside lamp globes, likewise from overheating. When failed they make the unmistakable burnt electronics smell...

i have been doing intense testings with this below kind lamps, only problem i have noticed so far, if u over heat them due no vent, their UVC output drops about 15%-20% . but never left them unvented over an hour in a unvented/sealed enclosure!
my units doesnt need to work over 10 min at a time, so 1 hour tests good enough for me! but i should do burn test, incase
some of the sensors fails!

https://www.osram.com/ecat/PURITEC%20HNS%20Compact%20L%20Lamps-PURITEC%20HNS%20Germicidal%20Lamps-Ultraviolet%20Lamps-Specialty%20Discharge%20Lamps-Entertainment%20&%20Industry/com/en/GPS01_3049001/PP_EUROPE_Europe_eCat/

Click to expand...

My 15w bulb has an edison base  looks like this. 

JR

JohnRoberts said:

An inverted 5 gallon beer fermenter, not sealed but no convection flowing.  I have had normal CFL bulb fail inside lamp globes, likewise from overheating. When failed they make the unmistakable burnt electronics smell... My 15w bulb has an edison base  looks like this. 

JR

Click to expand...

as long as i can let the heat going out, (travelling up) i am getting no heat problem...
those lamp's internal electronic ballasts are not very good actually, i heard/read!
they prone to fail! a lot of youtube videos for repairs, i came across when i was looking for tiny electronic ballast schematic!

It's apparently only on facebook, but a Chicago road case company has come up with a case that includes UVc sterilization.

https://www.facebook.com/MTcustomcases/photos/pcb.10156955546676296/10156955507831296/?type=3&theater

Looks like they use some kind of fluorescent tube. 

Pretty much everything I know about UV LEDs comes from Big Clive's youtube channel, but apparently UVc LEDs are still rare, expensive, and in a much less convenient form factor than regular LEDs.