Trying to square different units of measure in different references:
Persistence of coronaviruses on inanimate surfaces and its inactivation with biocidal agents kampf PRE PROOF
https://sci-hub.tw/10.1016/j.jhin.2020.01.022
The typical use of bleach is at a dilution of 1:100 of 5% sodium hypochlorite
resulting in a final concentration of 0.05% [13].
Our summarized data with coronaviruses suggest that a concentration of 0.1% is effective in 1 min (Table 3). That is why it seems appropriate to
recommend a dilution 1:50 of standard bleach in the coronavirus setting.
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1:50 is 2/100 is 20,000 parts per million (ppm) from 5% stock. That's an odd stock solution, unless hospitals make it themselves. Or does Clorox sell a hospital product to the trade ???
vs
Disinfecting and Sanitizing with Bleach
Guidelines for Mixing Bleach Solutions for Child Care and Similar Environments - 2015 WA State Dept Health.
https://www.doh.wa.gov/Portals/1/Doc...nfect-en-L.pdf
Background: Sodium hypochlorite is the active ingredient in household bleach or chlorine bleach.
It is economical, and is an effective disinfectant with a broad spectrum of antimicrobial activity. It has been the primary disinfectant used in early learning programs in Washington State for more than 30 years.
During this time, most household chlorine bleach was available at strengths of 5.25- 6.25%. The recommended concentration for disinfection has been 600-800 ppm of chlorine bleach and 50 to 200 parts per million (ppm) for sanitizing.
In 2012, some manufacturers changed their chlorine bleach formulation to a strength of 8.25% with a registered non-food contact surface disinfection level of 2400 ppm, the level often used in hospitals. Their sanitizing level is 200 ppm, the upper end of the range allowed by the Food and Drug Administration (FDA).
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It shows a chart to make 600-800ppm from 3 stock concentrations. But that is disinfection, not sanitization which I believe would be the 20,000ppm amount stated in the research paper.
But I don't know if there is a simple linear relationship, ie 33 x 600ppm amount = 20,000, because chlorine chemistry is a balancing act between several chemical species. So it might call for more or less than a linear amount of chemical. Anyone know?
I suppose 1:50 of a 5.25% stock won't be too strong, but 8.25% might be worth doing some math to get it correct.