The threat of COVID means it has never been more important to manage air quality in offices.
There is growing evidence that the virus can remain in the air as an aerosol as well as spreading directly from one person to another or by contact with an infected surface.
Stagnant office air represents a COVID risk to people in that environment.
Why monitor CO2?
Within any HVAC installation, we would expect to see CO2 already being monitored at the macro level. A typical system would set limits for CO2 based on factors affecting air quality across the office space, including airflow and forecast capacity. But standard systems rarely, if ever, take into account cellular spaces such as meeting rooms, for the simple reason that it has not been deemed necessary. Until now.
By distributing CO2 monitoring sensors in any cellular spaces within the office, employers and building managers can see if there are areas of high CO2, suggesting inadequate ventilation, as the gas builds up over time when spaces are poorly ventilated.
Even where air flow testing is in place or has been carried out previously, permanent CO2 sensors can be a worthwhile exercise. They work continuously and allow for human occupancy over time in enclosed spaces, for example during long meetings, so that systems can be adapted to ensure people’s comfort and wellbeing.
There are more advantages.
Benchmarking and compliance
Sensors with their associated software and analytics allow for CO2 monitoring as well as providing a record of monitoring.
Users can combine data about CO2 with readings from occupancy sensors – which measure when desks and meeting rooms are in use – to interpret what conditions give rise to inferior air quality. For example, conditions in a particular area of an office may vary depending on the numbers of occupants, which may require attention, but there could also be unexplained anomalies that need investigating.
With three simple steps – setting a benchmark for CO2 levels, monitoring the results and acting upon them – employers can demonstrate compliance with good air quality in the context of COVID, reassuring staff. What’s more the rise of smart building technology means that many employers will be able to share the data with building automation experts to support management of ventilation and potentially respond to changing conditions automatically.
It’s crucial that employers and building managers understand the ventilation systems in all their offices. The risk of viruses in aerosols suggests running ventilation systems at higher volume flow rates would be a good idea. To monitor the effect of this on air quality, it is important that sensors are installed at, or moved to, specific points related to mechanical ventilation hardware and automated windows.
CO2 monitoring is not only useful for ventilation monitoring as an addition to airflow metering. Even before the pandemic, employers have had a legal responsibility for air quality and ventilation in the workplace, and that includes keeping CO2 concentration below risky levels.
It might be thought that dangerous airborne material would only be found in factories or old office buildings with asbestos in the walls. In fact, CO2 is classed as a matter hazardous to health under UK regulations. The HSE publication Workplace Exposure Limits [EH40/2005 Workplace exposure limits] sets out boundaries for airborne concentrations of hazardous substances, which are calculated by taking an average of the levels over a specified period.
The limits for CO2 are:
- 5,000 parts per million (ppm) for long-term exposure (eight-hour average)
- 15,000 ppm for short-term exposure (15-minute average)
It’s important to note that these limits are boundaries rather than recommendations, and that even levels around 1,200 ppm are on the high side in terms of affecting human performance in the office workplace.
Benefits beyond COVID
There are good reasons to monitor and manage CO2 levels in the workplace beyond the war on COVID and legal compliance on hazardous substances.
As automated building management systems become the norm, good data is increasingly important to help those systems maintain the building environment at optimum levels. CO2 is clearly a key metric for that process.
Obviously, for this purpose reliability and accuracy are important. For that reason, Abintra uses NDIR (Non-Dispersive Infar Red), considered the standard for measuring the gas. Alternative cheaper solutions, typically branded as IoT, often use more basic components with an estimating algorithm.
From CO2 and beyond
Abintra’s environmental sensors also report on four other key metrics – humidity, temperature, noise and light – that help build up a picture to support design, building management and FM teams.
This may be part of an automated implementation, but even in buildings without fully automated management systems, data analytics provide building managers with real world intelligence so that they can adjust such parameters, aircon and ventilation being the most obvious.
Perhaps the real win is in a less obvious area, though. As employee wellbeing moves up the corporate agenda, the working environment is something that is attracting increased attention. Sit-stand desks that improve posture and reduce fatigue are an example. (Incidentally, Abintra has developed a sensor that can tell not only if a sit-stand desk is in use but at what heights it is being used over time.)
When it comes to working environment, there are few factors of more importance than air quality. Good, breathable air will certainly improve staff productivity, comfort and morale. Abintra installs environmental sensors for enlightened employers on exactly this basis.
CO2 sensors cannot defeat COVID by themselves, even when paired with other important tools such as occupancy sensors and automated building systems. They can, however, make a valuable contribution to the challenge of making workplaces as safe as possible while the threat of COVID remains. Not only that, sensors can help ensure compliance with UK workplace law. Perhaps most importantly beyond COVID, measuring CO2 and other environmental metrics equips building managers and their automated systems with the data they need to provide better air quality for a happier, more productive work environment.
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