3 or 6 feet in your district?
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Anonymous
| Name of your school district and is it using 3 or 6 feet distancing? If 3 feet was it always using 3 or only after CDC updated guidance? Thanks! |
Anonymous
It should make no real difference in re risk. But masks and ventilation will. We first apply our guideline to a typical American classroom, designed for an occupancy of 19 students and their teacher, and choose a modest risk tolerance, ϵ=10% (Fig. 3A). The importance of adequate ventilation and mask use is made clear by our guideline. For normal occupancy and without masks, the safe time after an infected individual enters the classroom is 1.2 h for natural ventilation and 7.2 h with mechanical ventilation, according to the transient bound, SI Appendix, Eq. S8. Even with cloth mask use (pm=0.3), these bounds are increased dramatically, to 8 and 80 h, respectively. Assuming 6 h of indoor time per day, a school group wearing masks with adequate ventilation would thus be safe for longer than the recovery time for COVID-19 (7 d to 14 d), and school transmissions would be rare. We stress, however, that our predictions are based on the assumption of a “quiet classroom” (38, 77), where resting respiration (Cq=30) is the norm. Extended periods of physical activity, collective speech, or singing would lower the time limit by an order of magnitude (Fig. 2). ... In both examples, the benefit of face masks is immediately apparent, since the CET limit is enhanced by a factor p−2m, the inverse square of the mask penetration factor. Standard surgical masks are characterized by pm=1to5% (73, 74), and so allow the CET to be extended by 400 to 10,000 times. Even cloth face coverings would extend the CET limit by 6 to 100 times for hybrid fabrics (pm=10to40%) or 1.5 to 6 times for single-layer fabrics (pm=40to80%) (75). Our inference of the efficacy of face masks in mitigating airborne transmission is roughly consistent with studies showing the benefits of mask use on COVID-19 transmission at the scales of both cities and countries (22, 33, 83). Air filtration has a less dramatic effect than face mask use in increasing the CET bound. Nevertheless, it does offer a means of mitigating indoor transmission with greater comfort, albeit at greater cost (22, 72). Eq. 5 indicates that even perfect air filtration, pf=1, will only have a significant effect in the limit of highly recirculated air, Zp≪1. The corresponding minimum outdoor airflow per person, Q/Nmax, should be compared with local standards, such as 3.8 L/s per person for retail spaces and classrooms and 10 L/s per person for gyms and sports facilities (72). In the above classroom example with a typical primary outdoor air fraction of Zp=20% (22), the air change rate λa could effectively be increased by a factor of 4.6 by installing a MERV-13 filter, pm=90%, or a factor of 5.0 with a HEPA filter, pm=99.97%. At high air exchange rates, the same factors would multiply the CET bound. https://www.pnas.org/content/118/17/e2018995118 |
Anonymous
| huh? The question was which districts in VA are using 3 or 6, not about the science. CDC has spoken there. |
Anonymous
The cdc distance rule is not based on good science. That’s the whole point of the peer-reviewed study out of MIT, just published in the NAS journal. So you can ask now 3 v 6 for your school but it’s pr a ly going in the trash by fall —- OBE. You should be asking what your school is doing about ventilation and masking, contact tracing. Etc. |
Anonymous
| Looks like ventilation lady, aka graphic designer, is back at it.. Let's let the professionals take care of this, OK??? |
Anonymous
If someone asked you what the federal government reported the unemployment rate was in a given quarter, would you wax poetic about studies that (whether correct or not) highlight the inadequacies of the metric, or just provide the data point. You’re high jacking a thread that isn’t about the science, it’s a question about what is happening in different districts. Non sequitur extraordinaire... |
Anonymous
She has a better grasp than the APE “safer at school” hacks. 
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Anonymous
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APS:
3’ classroom with 6’ for lunch Was previously 6’ classroom before CDC changed guidelines |
Anonymous
because the "professionals" did so well? |
Anonymous
please elaborate - what have they cited, other than actual data and science? pretty sure no APE members are not crafting their own graphs.. |
Anonymous
Same in FCPS. |
Anonymous
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LCPS 3' everywhere. Was 6' before.
They are using regular lunch tables in the cafeteria with every other seat blocked off. Definitely not 6' for eating. |
Anonymous
Where are they eating lunch? |
Anonymous
I'd like to know this too. Hearing Fairfax is getting kids back 4 days a week at 3 feet in classroom. How are they fitting them in for 6 feet at lunch? Do they actually do outdoor lunch? |
Anonymous
FCPS parent here. My sons class is split in half for lunch, half eat in the classroom and the other half in the cafeteria. Half eat their snack, while the others wait and then the second half eats their snack. There are classes at his school where they can all eat in the class. |