The BuildingAdvice Blog

Covid-19 Solutions: Let's Talk About Ventilation

Posted by Jim Crowder on Aug 27, 2020 11:00:00 AM

Reopen with Confidence Series - Covid-19 Solutions: Let’s Talk About Ventilation

Why ventilation is important right now 

Two weeks ago, we hosted an online seminar entitled “Reopen with Confidence.   We asked participants two questions to gauge how Covid-19 was affecting their business. 92% of respondents said that customers have been asking for help with Covid-19, and 67% could each name more than 20 buildings that would benefit having their indoor environmental quality checked (IEQ)76% could name more than 10 buildingsSo, there is a tremendous amount of opportunity to help customers you already know

You can take part in our latest Covid-19 Survey right here.

Covid-19 Survey 

Plus - you will see the survey results once you complete the six question survey ( 2 minute average completion time).

Completing an IEQ assessment provides you with real data about what is happening in the building over a period, whether it be a few days or a weekOne week supplies more than enough time to gather the facts. 

What’s changed about ventilation 

Ventilation is now at the top of list in building air quality conversationsGood ventilation is important to purge buildings of VOCs, control CO2 levels, and keep air fresh within the building space. With the desire to reopen commercial facilities, The CDC is recommending that occupants “Increase circulation of outdoor air as much as possible by opening windows and doors if possible, and using fans.” In the HVAC world this may mean turning off Demand Control Ventilation and fully opening the dampers on economizers. Evidence shows that well-managed airflow to populated sections of buildings will mitigate or reduce the likelihood of infection.  

Meeting rooms are especially important due to the number of occupants and meeting social distancing guidelines – if the ventilation system is not supplying enough fresh air, social distancing will not work as the meeting room becomes a confined space, trapping airborne respiratory particles (e.g. viruses)It may not be possible or practical to flood the building with “fresh” air if the climate is hot and humid, raining, or outdoor air pollution makes the situation worse, e.g. there is a large highway or freeway nearbyCost is an issue too – however there is no sense in “over-ventilation” if there is no needCO2 levels are a good proxy for human-generated contamination levelsLow CO2 readings could mean the ventilation system is oversupplying enough fresh air given occupant levelsConsider lowering CO2 thresholds from current ASHRAE guidelines from 1000 ppm to readings that account for the need for social distancing and concurrent occupancy levelsThe CDC is also recommending that lavatory exhaust fans be checked to ensure their operating correctly.  

Considering the discussion above, we recommend that you assess multiple areas in the building to ensure there is enough ventilation in every occupied areaIt may take a few days longer, but having more information enables a better overall assessment (and outcome)Your customers will need your help refining and implementing their ventilation strategy. 

Issues you should consider when making ventilation recommendations: 

  • Local weather conditions, humidity concerns, and cost 
  • Demand control ventilation settings 
  • Fixed fresh air ventilation dampers 
  • Filtering outside air 
  • Air purification technology 

High Weekend CO2 Levels in a House of Worship 

Here is a recent sample, taken from a House of Worship in the upper mid-west when the facilities were in heating modeThe CO2 levels are fine during weekday operations where levels are well below the 1000 ppm threshold. As we move into Saturday and Sunday, it is evident that services which will cluster worshipers into an enclosed space significantly raise CO2 above 1000 PPM. In and of itself, higher C02 levels will not be a health or safety issue. But their presence at these levels and for these durations with occupant density indicates poor ventilation increasing the likelihood of spread of any virus present.   

Knowing schedules and the impact of these types of gatherings, Mechanical Contractors can help reduce the risk of spreading infection by devising solutions that ensure better ventilation during such events as well as the implementation of filtration and purification solutions.   

Weekend CO2 Levels in a High Occupancy Building  

Be the Expert Without Having tConduct Science Experiments 

Surveys show your customers are searching for informed recommendations. Rather than guiding with hunches and opinions, recommend conducting a Site and IEQ assessment to use their building performance data to guide a carefully thought out set of recommendations. Real data helps make better decisions, and with an IEQ assessment in hand, you have all you need for a great discussion with your customer. 

Give us a call if you need help interpreting a report or making recommendations. We will be happy to helpYou can also check out our resource page, 

Next Step 

Think about which customers are likely to have CO2 issues related to occupancy.   

Be safe, and get out there!


Jim Crowder 
CEO, BuildingAdvice 

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