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Disinfecting fabric seats

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  • #16
    Actually, you don't even need distilled water in most western countries, because tap water is clean enough in many cases... If you can drink it, it's good enough for your hands or surfaces. The only problem is that when you use it as part of disinfectant for surfaces, is that it can leave some residue, mostly due to de dissolved calcium. Those stains can be easily removed though.

    Right now, we're using denatured ethanol as base for the disinfectant my wife's little operation is running, because we can procure it relatively cheaply from a local distiller, who's cooperating with us. The price for both ethanol and isopropyl alcohol//2-propanol on the current public market is totally overpriced, prices like 20 euro per liter aren't uncommon for small volumes... Sometimes you can find some old stock for reasonable prices though.

    If you mix your own disinfectant, make sure the amount of ethanol/2-propanol is at least 70%. You need 60% to be effective, but leave some room for error. Keep in mind that not all sources are 100% pure grade, most ethanol is 96%, because normal distillation doesn't give you a higher percentage. To remove the remaining 4% water, you need to apply chemical filtering processes. Also make sure that, if you're using ethanol, the denaturing agents aren't irritating for the skin.

    Soap will also kill the virus, but soap isn't practical to sterilize surfaces. If you want to disinfect your hands, washing them with soap is still the preferred way. SARS-CoV-2 is an encapsulated virus, so in order to destroy it, you need to remove the fatty encapsulation it is protected with. This is what ethanol/2-propanol is doing in disinfectant, the same for detergent in soap. Once the virus is exposed to the "open air", the protein structure will fall apart and effectively destroy it.

    The warmth of your hands, combined with the rubbing (increased heat and surface contact of the disinfectant), will destroy the virus within about 20 seconds. On surfaces, the rule of thumb is 60 seconds in combination with disinfectant, but it depends a bit on the kind of surface. To be on the safe side, you should take about 5 minutes into account.

    Killing the virus with UV-C light is also an option, but keep in mind that UV-C light is harmful for both your skin and your eyes. We're currently looking at UV-C based disinfection methods, like disinfecting a shopping cart with UV-C or other smaller objects with UV-C, but the research on how much UV-C light exposure you require to be sure you effectively destroyed the virus, is still mostly "up in the air".

    For a small reference: A UV-C bulb of about 40 Watt is seemingly capable of disinfecting a room the size of an average living room within 1 to 1.5 hours. The problem is that not every surface is directly exposed to the UV-C light-source. While bounced-back light still is effective, it is obviously less effective than direct exposure. In a cinema, it will be pretty hard to evenly light the entire room with UV-C light. Also, you must make absolutely sure, nobody enters the room while the disinfection process is ongoing...
    Last edited by Marcel Birgelen; 04-26-2020, 08:00 AM. Reason: For some reason, autocorrect flipped ethanol to methanol... pretty dangerous stuff...

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