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How to Slow the Transmission of Viruses in your School Building

How to Slow the Transmission of Viruses in your School Building

By Raj Setty

As everyone grapples with where to start hardening their building and making it ready for re-opening, there are some simple things to do. I won’t cover the basics like sanitizers or limiting occupancy in elevators but will focus on how to slow the transmission of viruses in your building and delve into how to improve the nurse’s station to better isolate students who may become ill.

Step 1: Maximize your outdoor air from your building air handler. The simplest way is to run your air handler longer, 2 hours before and after occupancy. Yes, you will have more energy costs but no capital costs.

If you have no air handler fresh air capabilities, try to open windows. Avoid mold and introducing poor air quality in your space.

Step 2: Change your filters on the main air handlers to MERV 13 in the rooms that see the most occupants. If your space starts to feel a lack of cooling or heating because the filters are blocking air flow at peak conditions, then go back to your previous filter. Don’t go down the path of costly motor changes until you start to see performance degradation in real time.

All maintenance staff should wear PPE when working on air handlers, changing filters and in mechanical rooms. The last thing we want is to have distribution of the virus propagated when changing filters.

Step 3: All maintenance staff should wear PPE when working on air handlers, changing filters and in mechanical rooms. The last thing we want is to have distribution of the virus propagated when changing filters.

Step 4: Install sanitizing mats at the entrances. It is very difficult to sanitize and disinfect floors so let’s disinfect shoes and slow transmission.

Step 5: Do a Test and Balance of your system. We have the theoretical numbers of how much fresh air the unit can bring in, now let’s get the real number with a TAB. All equipment degrades and goes out of adjustment with run time hours. Time to get it re-tuned.

Following those five steps is a solid start to increasing the safety of your school, but what happens if a student gets sick? Getting prepared for that eventuality is also an important consideration that raises many questions.

How do we efficiently move a potentially sick student out of a classroom, into an isolation suite and out of the school? How will we start to protect nurses? Use a common-sense approach in your plan for a nurse’s suite to elevate it to a hospital-grade level.

We want to ensure that if a sick child goes to either of the nurse’s stations, that we do not re-entrain potential viral load into the HVAC return air system and then get re-distributed.

First identify a nurse’s suite or nurse’s station in the school. Most schools have this. I recommend identifying a second room or space where you can bifurcate your sick student flow. Similar to a hospital where there are many types of spaces and rooms, create a normal operational nurse’s suite and an isolation level nurse’s suite. For both types, take the walls up to the ceilings and have the ability to block all return air from going back to the main air handling systems. We want to ensure that if a sick child goes to either of the nurse’s stations, that we do not re-entrain potential viral load into the HVAC return air system and then get re-distributed.

Now the nurse’s isolation suite will follow the ASHRAE 170 standards and guidelines for infectious control.

This is defined technically as an Airborne Infectious Isolation room (AII). Some of the main features are as follows:

  • Keep it under negative pressure in relation to adjacent spaces.
  • Proceed with a 100% Outside Air Supply
  • Design your systems to handle up to 12 Air Changes of Air in the space – operational you can ramp it down when unoccupied
  • You can re-circulate air per ASHRAE if you run it through a HEPA filter but since these spaces are small go with a 100% OA system
  • All the air is exhausted to the outside
  • HEPA filter and UV-C prior to exhausting to reduce any viral load
  • Consider an AnteRoom where the Nurse can place a higher level of protective gear to tend to the student.

These spaces will require building modifications and will need to be budgeted in future capital plans. In the interim, create a space outside or even consider a temporary trailer or mobile RV type nurse’s suites. Apply common sense and thing about the numbers of sick students your school will want to handle per hour. Visit the previous year’s load profile of students to the nurse during the peak of flu season. If an elementary school with 300 kids for example, averages 1-2 kids per hour to the nurse’s suite, then consider 2 spaces identified or temporary to temporarily house the child before they leave the school.

All AII must be cleaned and disinfected between uses and see a minimum of 12 air changes of OA before the next student is brought in. We are trying to reduce the risk of virus transmission in a school, so we need to efficiently and kindly move children who could be sick out of the building.

Adding a hospital-level nurse’s station/Airborne Infectous Isolation Room will increase your school’s ability to handle any student illnesses in a way that is safer for all concerned. Add it to the Five Steps, and you have a good start to help your facility increase its safety for students, faculty, and staff.

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Watch the Webisode

Raj Setty, President of Setty & Associates International and Joseph Khoury, Founder & EVP of Pre-construction at MCN Build, discuss  their views on leadership in challenging times, and the critical items to consider when making facilities upgrades for a safer school opening in Fall 2020.

Raj Setty

ABOUT THE AUTHOR

Raj Setty

President, Setty & Associates, International

Mr. Setty is currently President of a full-service mechanical, electrical and plumbing consulting engineering firm headquartered in Washington DC, with 8 offices across the Mid-Atlantic region. Setty specializes in institutional projects, energy modeling, commissioning and high performance buildings. Currently, there are over 250 projects in design or construction with 25 different universities and 20 school districts across the country.

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