ISO Recommendations for wiping equipment surfaces / sanitizing

[Andrew Leist]

Our university has half a dozen projection booths that are all run manually (no schedules), so projectionists are usually in there touching the DC projectors, curtain/masking controls, Dolby gear, etc. Any recommendations for sanitizing touch screens, knobs, & buttons? I'm thinking alcohol wipes, but wondering if there's a more appropriate choice for expensive equipment.

[Randy Stankey]

Alcohol and distilled water.

Use either isopropyl or ethyl. Your choice. Most places use iso because ethyl is drinkable. We don't need people getting loaded at work.

Greater than 50% alcohol to water but less than 75% alcohol to water. (Volume to volume.) 60% alcohol is common.

Dilute alcohol kills bacteria and viruses better than pure alcohol. (Techinically, ≈99.95% because of the chemical nature of alcohol but I digress.)

Alcohol kills viruses by denaturing its proteins, causing them to bunch up and tangle. Undiluted alcohol can't penetrate the barrier created by these denatured proteins as easily. Adding water to the mix dissolves denatured proteins and allows the alcohol to work faster. Also, diluted alcohol takes longer to evaporate. Thus, the alcohol stays on the surface being cleaned longer, giving it more time to work.

The place where I work is an ISO certified shop (among others) and we do a lot of contracts for critical industry, life-supporting medical, aerospace and military use. For that reason we have to jump through a lot of crazy hoops in regard to sanitation of work areas, etc.

Every night, before going home, we have to stop working fifteen minutes early in order to clean and sanitize our work stations and equipment. There are five gallon buckets with screw-on lids containing disposable, microfiber cleaning wipes saturated in 60% alcohol. We just go get a handful of wet wipes and go to town.

We have binocular microscopes, air driven syringe dispensers, air hoses, handheld barcode scanners, computer screens/keyboards. Some workstations have oscilloscopes and other test equipment. Then, of course, we have to clean everything we touched during the workday, including the bench tops, anti-static mats, our hand tools and the chair we sat on.

We've been doing this every day, two shifts per day, for over a year, now, and I don't recall one incident of any equipment being damaged by careful cleaning with alcohol and water. Just be sure to wring out the cloth so that it's not dripping wet before using it on any electronic equipment.

I can't think of any equipment in a projection booth that is more sensitive than an electronics workshop.

If we use alcohol to clean the place, I can't imagine any reason you can't use it to clean a booth.

[Carsten Kurz]

We create our own surface sanitising agent by dilluting 99.9% isopropyl (cheap) with distilled water (there is a WHO recommended formula). Not sure if it's safe on any touchscreen technology, but if it's not overused dripping wet, it should be okay. In general, however, soap is sufficient to sanitise surfaces, it just takes longer to take effect, alcohol based sanitisers are better for cyclic usage during daily operation. If the surface is left over night, lightly soaped water should be okay as well.

[Andrew Leist]

Randy & Carsten, thank you both. Very helpful, and much appreciated.

[Mark Gulbrandsen]

"Bleach, ammonia and hydrogen peroxide are all good examples of products that can disinfect.
Approved disinfectants against coronavirus include: Clorox Multi Surface Cleaner + Bleach Clorox Disinfecting Wipes Clorox Commercial Solutions"

[Barry Floyd]

Would any of these recommendations have any affect on things like control panels or plastic knobs that might have silk-screened writing or marking on them? Would hate to find out the hard way that although the surface might be clean, you could no longer read the markings on the surface.

[Randy Stankey]

The parts I make in the factory go to the marking department, afterward, where they are labeled using an industrial ink jet machine then baked to set the ink. After we get them back they have to be cleaned before being sent to final test. We clean them either by hand with pure iso-alcohol or in a degreasing machine filled with what is essentially dry cleaning fluid. The marking doesn't come off when we clean them that way.

In fact, marking permanency is one of the tests the QC department does during final inspection.

It is certainly good to be mindful of any markings you apply alcohol to but, if they are properly applied and QC'ed, I don't think there should be any problems with markings coming off.