1/ #VENTILATION is a key factor in #SafeSeptember for #onted. In this thread I& #39;ll cover:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">My immediate 3 asks of @sfleece and @fordnation

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">A suggested room-by-room assessment and implementation methodology

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Who to follow
1/ #VENTILATION is a key factor in #SafeSeptember for #onted. In this thread I& #39;ll cover:https://abs.twimg.com/emoji/v2/... draggable=My immediate 3 asks of @sfleece and @fordnation https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">A suggested room-by-room assessment and implementation methodologyhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Who to follow" title="1/ #VENTILATION is a key factor in #SafeSeptember for #onted. In this thread I& #39;ll cover:https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">My immediate 3 asks of @sfleece and @fordnation https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">A suggested room-by-room assessment and implementation methodologyhttps://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Who to follow" class="img-responsive" style="max-width:100%;"/>
2/ My immediate asks of Ontario:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="1⃣" title="Tastenkappe Ziffer 1" aria-label="Emoji: Tastenkappe Ziffer 1"> Update the Guide to Reopening Ontario& #39;s Schools to add #ventilation, currently absent. I recommend using Schools for Health: Risk Reduction Strategies for Reopening from Harvard School of Public Health https://schools.forhealth.org/risk-reduction-strategies-for-reopening-schools/healthy-buildings/">https://schools.forhealth.org/risk-redu...
Healthy Buildings

Healthy building strategies that improve air quality and clean surfaces should be incorporated as part of a layered defense against COVID-19.

https://schools.forhealth.org/risk-reduction-strategies-for-reopening-schools/healthy-buildings/
3/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="2⃣" title="Tastenkappe Ziffer 2" aria-label="Emoji: Tastenkappe Ziffer 2"> Also update the Guide to Reopening Schools to reflect current knowledge regarding the relative importance of airborne transmission of COVID-19 compared to surface transmission.
4/ Final immediate ask of #Ontario:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="3⃣" title="Tastenkappe Ziffer 3" aria-label="Emoji: Tastenkappe Ziffer 3"> Require that each school room be *measured* for occupant spacing and outdoor air ventilation. Prior to occupancy, each room should have a maximum COVID-19 occupancy posted on the door, with operational requirements of the room,
5/ such as placement of portable air cleaner and speed setting, window or ceiling fans on/off.

This must be done PRIOR to occupancy. Some rooms may end up with a temporary occupancy of 1 or 2 people if a ventilation system is broken.
6/ Here is a possible methodology to ensure school room risk from airborne transmission is reduced.
Steal it, improve it!

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Examine all central equipment and maintain, repair, upgrade, and measure:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Tighten fan belts (increases air flow), fully open outdoor air dampers,
7/ install better filtration (MERV-13).

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">After the repairs and upgrades, measure the airflows to determine the maximum actual outdoor air volume being supplied.

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">For exhaust-only systems, the same applies but there is no filtration, and only measure the exhaust air flow.
8/
With the central systems known, do a room-by-room physical assessment:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Measure room dimensions. Calculate floor area and room volume.
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Photograph all walls and ceiling. Determine all HVAC equipment present.
9/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">*Measure* the air volume rate entering and leaving from all supply air diffusers, return air grills, exhaust fan openings.

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Examine & photograph all windows. Determine current and maximum possible open area and area orientation (h vs w), mention outdoor air concerns,
10/ and what repairs are needed (are window cranks missing?)

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">For rooms served by central systems, use the measured air flows with engineering calculations to determine the outdoor air supplied to the room. Consider using a tracer gas (CO2) as a proxy in some situations
11/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Determine occupant capacity based on minimum allowable proximity, accounting for built-in and movable furniture. Should be 2 meter radius, don& #39;t lower until public health guidance & science allows it.
12/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Given the room dimensions, determine the minimum outdoor air requirements by ASHRAE Standard 62.1 for different occupancy scenarios: ASHRAE default, actual typical for the room (almost always higher than ASHRAE), and maximum occupancy (fire or structural limit).
13/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Translate the volume of outdoor airflow into air changes per hour for the room. Should be approx 3 ACH. Current suggested COVID-19 ventilation by @ShellyMBoulder is around 6 ACH, or approx double the ASHRAE amounts: https://twitter.com/ShellyMBoulder/status/1289993688039399424?s=20">https://twitter.com/ShellyMBo...
14/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Check measured outdoor air volume against various required amounts, and improve:

https://abs.twimg.com/emoji/v2/... draggable="false" alt="🪟" title="Window" aria-label="Emoji: Window">Under some ACH threshold (TBD) or with natural/exhaust-only ventilation, select a portable HEPA air cleaner. Calculator here: https://twitter.com/ShellyMBoulder/status/1291071670313050112?s=20">https://twitter.com/ShellyMBo...
15/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🪟" title="Window" aria-label="Emoji: Window">Consider box fans in windows (best practice of pointing in or out or both, and/or taping a furnace filter to inlet still TBD) to force air changes and filter pollen/pollutants from outdoor air. Natural ventilation from windows is NOT reliable!
16/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Determine maximum occupancy given all factors. Be open about how it is determined - it& #39;s not a hard limit, though if equipment is inoperable some rooms may only be suitable for a single occupant.
17/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Post a sign on the door indicating maximum COVID-19 occupancy and indicate how the room is to be operated:
-Door, windows open/closed
-Fans on/off
-Portable air cleaner settings and location
-Who to contact for questions/issues
18/
https://abs.twimg.com/emoji/v2/... draggable="false" alt="🔸" title="Kleine orangene Raute" aria-label="Emoji: Kleine orangene Raute">Place/install an inexpensive temperature/RH/CO2 meter in the room along with recommended limits and actions to take.

As temperatures fall, further decisions and actions will be needed to address relative humidity and temperature.
19/ After the immediate needs are taken, the capital repair planning can be started. The photographs and measurements will be valuable.

Let& #39;s make permanent changes. Improved indoor air quality improves many aspects of health and performance.
20/ There will be increased energy use with proper ventilation. Thankfully there are many ways to address energy and emissions, so don& #39;t let that get in the way of action. The many benefits of improved indoor air quality are worth it.
21/ Need more technical detail? ASHRAE is the place. They have made relevant standards available online for free! Check it out: https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards">https://www.ashrae.org/technical...
22/ ASHRAE continues to update its COVID-19 resource page. Deep link to Schools and Universities section: #schools">https://www.ashrae.org/technical-resources/resources #schools">https://www.ashrae.org/technical...
23/ Some clarifying information.
When talking about ventilation in this context, it& #39;s outdoor air volumes provided, in cubic feet per minute or liters per second. (5 L/s approx = 10 CFM)
24/ While a "stuffy" room is an indication of poor indoor air quality, a stuffy room can feel much better with A/C, which removes moisture and moves the air around - but without outdoor air and filtration, it& #39;s still just as unhealthy as before.
25/ more to come...
26/ Some FAQ& #39;s.
https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">Why not install HEPA filters?
If it even fits, too much pressure drop, causing large airflow reduction (bad). A MERV-13 filter is kind of like an N90 mask (pretty good!) & is good balance between pressure loss and filtration. HEPA more like N100 mask.
27/ https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">How does more frequent filter changes help?
Filters are often changed out when the pressure drop reaches a set amount. Following the fan performance curve, the flow reduces as the resistance increases. Change out earlier to have less pressure drop.
28/ https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">My classroom doesn& #39;t even have an HVAC system!
Heating: Yes
Ventilation: Yes, but might be exhaust-only, with makeup air coming in through cracks or a makeup air system. Very old schools had natural ventilation (chimney effect) but (should) be using exhaust fans now.
29/ Compare: many homes have no (outdoor air) ventilation system at all! In 2000& #39;s most have a primary exhaust ventilation fan, supposed to run 24h/day. More recently we finally have effective and energy efficient ventilation systems like HRVs in homes.
30/ https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">My school is too old!
I& #39;d be more concerned about some schools designed to 1980& #39;s ventilation standards, caused sick building syndrome. Seems we& #39;re coming around back to 1900-1940& #39;s levels by recommending double the ASHRAE minimum for optimal health.
31/ Some more interesting history of older schools in this September 1999 ASHRAE Journal article:
32/ https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">The school board says "all HVAC equipment has been assessed to ensure it is operating as designed"

Ask:
1) which design, 1980& #39;s?
2) how do you know, was anything measured?
3) are there records for proof?
33/ https://abs.twimg.com/emoji/v2/... draggable="false" alt="💬" title="Sprechblase" aria-label="Emoji: Sprechblase">Tell me more about air cleaners
This thread by Jose-Luis Jimenez. Even includes a link to a sizing calculator for classroomshttps://abs.twimg.com/emoji/v2/... draggable="false" alt="👉" title="Rückhand Zeigefinger nach rechts" aria-label="Emoji: Rückhand Zeigefinger nach rechts"> https://twitter.com/jljcolorado/status/1291758303089852417">https://twitter.com/jljcolora...
34/ Ventilation is NOT a substitute for lack of masks and physical distancing! Make indoors be more like outdoors in terms of air quality. Otherwise, poor ventilation increases risk. https://twitter.com/KashPrime/status/1298282154481324034?s=20">https://twitter.com/KashPrime...
35/ In safety language, ventilation is an engineering control. Masks are normally last resort PPE, but masks are also a form of source control, and so masks can be considered an engineering control too. Require masks in schools!
36/ PEOPLE TO FOLLOW on ventilation/air quality - so much to learn!
Dr. Shelly Miller @ShellyMBoulder;
Jose-Luis Jimenez @jljcolorado;
Dustin Poppendieck @Poppendieck;
Joseph Allen @j_g_allen;
Marina Eller Vance @marinavance;
Linsey Marr @linseymarr;
Dr. Richard Corsi @CorsIAQ
37/
This is an opportunity to begin making schools healthier, where disease is prevented rather than incubated, and indoor environmental quality allows students to reach their full academic potential.

Hey @fordnation want to academic scores improve?
Fix our schools.
38/
Almost six months later.
Why can& #39;t we do this here? https://twitter.com/ReicherStephen/status/1380414292151967744?s=20">https://twitter.com/ReicherSt...
/39 adding this great thread from @marwa_zaatari: https://twitter.com/marwa_zaatari/status/1383828012022439937?s=19">https://twitter.com/marwa_zaa...
You can follow @DavidElfstrom.
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