Thread by @smartrestartaps

1/ ASHRAE (professional engineering org for HVAC professionals) has a technical committee on the design of educational facilities that has released new guidance on how schools can achieve “advanced indoor air quality.” @SuptDuran @jmayo443 @APSFacilities

2/ The complete report can be found here, but a 🧵 to sum up some of the ideas. APS falls very short on most of this, but its our hope that new buildings will be built with some basis of best practice and health — optimal conditions for learning.
ashrae.org/file%20library…

3/ First, verify, test, and balance HVAC systems, including direct measurements from at least 10% of classrooms, at a minimum.

MINIMAL testing should include CO2 levels are being maintained at <750 ppm over outdoor air. Also levels for PM2.5 and toxic volatile organic compounds.

4/ Second, calculate if you want to protect from airborne infection at a certain risk level, like 1% risk, or 10% risk, etc., and share your basis for calculations with your school community so everyone knows it.

5/ For advanced IAQ, very high priority is given to replacing/upgrading systems so they will have MERV-13 or MERV-14 filters. Also, to adding HEPA filters in spaces that have higher density of people or higher risk people/risk of infection, so the air is free of germs, particles.

6/ The amount of air changes as a “base minimum” for any space where COVID is likely to be present is 6 air changes/hour.
This relates specifically to health clinics and nurses’ offices. The school “advanced IAQ” report requires 12 ACH for isolation room, 10 ACH for waiting room.

7/ ASHRAE directs schools to deploy IAQ sensors for CO2 levels, particles, and toxic compounds in a minimum of 10% of classrooms.
Advanced systems should have 1 sensor for every 2-4 rooms (depends on size).
Readings to be taken daily; data compiled for 6 months for analyses.

8/ Minimum airflow is 3-6 ACH outdoor air. But new ASHRAE report states a better IAQ goal is 6-8 air changes per hour. (😉 @SuptDuran, @APSFacilities)

Also, HVAC systems should be set at 100% outdoor air, for central air, and 30% ABOVE code for dedicated outdoor air systems.

9/ HVAC equipment shouldn’t be loud (like many APS systems are); nothing noisier than 40 dB in a classroom, ASHRAE recommends.

Multiple (often can be set at quieter speeds) HEPA air cleaners can be used when HVAC systems are inadequate to provide 6-8 ACH — or more — as desired.

10/ Lots of clear information on air cleaner placement, which APS doesn’t typically follow in classrooms we have visited. Sometimes individual teachers do their own research, amid the lack of guidance.

11/ Schools should prioritize all bathrooms meet code, then consider adding upper-room germicidal UV, extra exhaust capacity (15% above code), extra air filtration, touchless plumbing, etc.
Strong set of recommendations here to make public school bathrooms less gross.

12/ The guidance recommends germicidal UV technology in high density, high changeover spaces.

Use of as germicidal UV was listed as a “base minimum” standard — it’s not new!

Advanced schools would use it in all high volume spaces— places like gyms, cafeterias, auditoriums, etc.

13/ Medium priority tasks include operable windows, energy efficiency work — including utilizing HEPA cleaners as an energy efficient way to offer healthier air, and focusing on humidity controls.

14/ That’s a wrap on this summary. At this point, there’s really no excuse for APS to be spending hundreds of millions of dollars on new facilities without following best practices. Yes, the goal posts have moved. So adapt, APS.

@threadreaderapp unroll please.

Almost forgot to tag this: #CleanTheAir