Mitigation Recommendations

So you’re entering the mid-risk zone , or your COVID transmission risk is high?

Rule no. 1: don’t panic.    

You’ve been alerted so that you can do something to look after the people in those spaces – because that’s what’s it’s all about isn’t it? – Health and Safety. 

Here are some things you can put into your mitigation strategy; and remember, it’s YOUR strategy, some responses may not be possible or relevant; no worries, do what you can and then monitor, track and respond accordingly. 

Rule no. 2: things change.  

Weather, number of people, activity, all these things affect CO2 readings in an enclosed space. And they affect them minute by minute, hour by hour, day by day and month by month. So expect change, expect to move into increased risk zones and take action to decrease. And then expect to do the same again.  

Rule no. 3: Mitigating COVID transmission risk is about VENTILATION.  

You want to get an exchange of air. This is vital, it’s not about recirculating the air in the room, it’s about exchanging fresh, healthy air for old, rebreathed air, which has come from people’s lungs as they exhale. (If one of those people is asymptomatic but is able to exhale COVID aerosols into the shared air.... you get the picture. ) 

Mid-Risk Zone: Risk is increasing

 

This is the chance you have to decrease and mitigate risk with mostly human intervention.  

• Open a window and/or a door 

One window/one door may not be sufficient. You’re looking for a cross breeze; a movement of fresh air coming into a room and a flow of old air out the room.  

If possible 

• reduce the activity in the room 
• reduce the number of people in the room  

This is something that could be looked at over a period of time:  

Is there a larger, better ventilated room where this gathering of people could take place?  

Could the amount of people be split? Either into more rooms or by staggering the time that people gather (canteen/lunch breaks/) 

Could this meeting happen outside?  

• Track meetings/classes to ascertain the maximum length of time a meeting/class should last. Keep within that time limit 
• Let the room “breathe” between meetings/classes 

High-Risk Zone: Risk is high 

You may or may not have had the time to put your human intervention strategies in place (see above). If your risk has escalated quickly, put the above strategies in place and monitor.  

If the room remains at high COVID transmission risk, mechanical intervention can be introduced. It is possible to start slowly and track how the room performs.  

• Using a fan to ventilate.  

It is important that you create an exchange of fresh air for stale air, you are not simply looking to circulate stale air around the room. Determine which window/door allows the air to blow into the room; place an electric fan in front of the window/door where the breeze enters, pointing into the room. You can use a standard tall fan on a stand or place a box fan on a table in front of the window/door.  

Place a second fan pointing out of the window or door on the other side of the room. While it seems counter-intuitive to blow air out of the room, this will create a circulation through one window and out the other. 

Alternatively, if you have an extraction fan fitted in your room, use it now or purchase a window exhaust fan that fits directly inside your window sill. 

• Portable air cleaning units 

This is an option if increasing natural ventilation isn’t a suitable long-term solution: the room either has windows that restrict opening or is next to noisy environments that interrupt concentration.  

You will need to ascertain the volume of the air in the room as different units purify different volumes of air.  

To calculate the volume of air in your space: height of room x length of room x width of room (see? You did need that maths after all!) 

Most businesses use this strategy in one or two rooms to track the impact of this strategy. In the longer term, this then informs more permanent mechanical intervention, especially for rooms at consistently high risk with a lot of people expected in the space. (preparing for when people return to work). 

• HVAC (heating, ventilation and air conditioning) systems 

And here’s the rub:  

There are many different types of heating, ventilating and air conditioning (HVAC) systems. It is important to understand that not all heating systems include ventilation, some will only heat or cool or recirculate (and not provide fresh air). 

Not all HVAC systems are air purifiers and not all HVAC air purifying systems have the correct filters to filter out virus particles. There’s more: not all air-purifying HVAC systems purify the required volume of air to clean decrease COVID transmission risk.   

If you have an HVAC system 

• As a short-term measure, operate it at its maximum fresh air intake and then call your provider to ask  
• does the system recycle air, or use fresh air? 
• can the ratios of fresh air and recycled air change? 
• is there a filter in the system and what type is it? 
• what is the maximum feasible air change rate the system can deliver? 

If you don’t have an HVAC system 

• Call some providers and get a quote 
• Reach out to us and we’ll introduce you to our trusted network.  

And then track, track, track: track the impact of your strategies - our monthly reports will help – and you’ll be able to demonstrate your Health and Safety COVID response and have the data to present recommendations to your governing bodies.  

Thank you for caring for your air and the people who share it

We’re here to support you. 

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The Tether Team