Wow, this is what I've been advocating for Ontario school boards since August!
The School District of Philadelphia is measuring the outdoor air amount supplied by mechanical #ventilation of every room in every school. THREAD #onted
The School District of Philadelphia is measuring the outdoor air amount supplied by mechanical #ventilation of every room in every school. THREAD #onted
https://twitter.com/PHLschools/status/1321814443320397825
They use 15 CFM per person of outdoor air as the threshold.
Technically, ASHRAE Standard 62.1 is 10 CFM/person plus 0.12 CFM/sqft. If there are 18 persons in a 750 sqft room it works out to the same.
You can view the ASHRAE standards from this page: ashrae.org/technical-reso…
Technically, ASHRAE Standard 62.1 is 10 CFM/person plus 0.12 CFM/sqft. If there are 18 persons in a 750 sqft room it works out to the same.
You can view the ASHRAE standards from this page: ashrae.org/technical-reso…
Back in August, I recommended posting a sign on each school room:
https://twitter.com/DavidElfstrom/status/1298001345165877250?s=20
The School District of Philadelphia is posting a sign with max occupancy, but isn't including any special instructions for the operation of the room. The methodology is the same: Ventilation or distancing, whichever is the limiting factor.
All of the reports are posted publicly. You can view the air balancing report for each school at this Google Drive folder at this link: drive.google.com/drive/folders/…
Many rooms are limited by the the available outdoor air ventilation. If the ventilation is sufficient, distancing for a typical classroom limits occupancy to 15 (14 students and 1 teacher). Some rooms are not to be occupied at all.
Unlike other jurisdictions, Philadelphia doesn't mention of increasing the effective clean air rate with portable air cleaners.
You can use this spreadsheet tool developed by Harvard T.H. Chan School of Public Health and University of Colorado Boulder tinyurl.com/portableaircle…
You can use this spreadsheet tool developed by Harvard T.H. Chan School of Public Health and University of Colorado Boulder tinyurl.com/portableaircle…
In Ontario, both the air balancing testing and purchase of portable HEPA air cleaners can be funded by the Ministry of Education, as described in the August 25 Memo B12 "Optimizing Air Quality in Schools". efis.fma.csc.gov.on.ca/faab/B_Memos_2…
Using the Ontario school list with enrollment and age of each school, I made the following chart. It shows approximately 65% of #onted students are in buildings with less than the current design standard of 15 CFM/person of outdoor air.
Demand #HeroicVentilation (@linseymarr). Supplement with filtration.
Demand capped class size to #ventilation or distancing, whichever is fewer occupants.
Demand #masks4all grades.
Accept #aerosol transmission and implement controls based on it.
Demand capped class size to #ventilation or distancing, whichever is fewer occupants.
Demand #masks4all grades.
Accept #aerosol transmission and implement controls based on it.
Appendix A: Follow the RISK REDUCTION STRATEGIES FOR REOPENING SCHOOLS report from Healthy Buildings Program, Harvard T.H. Chan School of Public Health. The Buildings section is most applicable to ventilation, but it's all great:
schools.forhealth.org/risk-reduction…
schools.forhealth.org/risk-reduction…
Appendix B: The nitty gritty of measuring outdoor air amounts in classrooms, including how to use a CO2 logger is described in 5 STEP GUIDE TO CHECKING VENTILATION RATES IN CLASSROOMS also by Harvard T.H. Chan school of public health: schools.forhealth.org/ventilation-gu…
@threadreaderapp unroll
One minor note. The School District of Philadelphia appears to be using the 44 sqft/student guideline for social distancing. It can probably be around 21 to 23 because of the walls. The long story of where this came from is in WIRED. wired.com/story/44-squar…
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