Monday, April 25, 2022

Beyond monitoring Indoor Air Quality (IAQ)

Without any hard stats, it is safe to say that there has been a proliferation of messages from system integrators and real estate operators alike promoting Healthy Buildings. They base this on monitoring and displaying Indoor Air Quality (IAQ) data to the building tenants, and alerting people when the air quality is detrimental to the health of people. There are many commercial IAQ sensors that support collecting and displaying a variety of air quality factors. For example, using the iAeris Azure Sphere device from Sysinno, we created a simple dashboard using the ICONICS GENESIS64 IoT software:




Air Quality Monitoring Solution with ICONICS and Sysinno | ICONICS Software Solutions

But just monitoring indoor air quality does not actually solve the problem, and there are some simple and effective ways to address this. Here are a couple of common strategies:

  • Using air purifiers. In regions where the outside air quality is poor at times, some companies have installed air purifiers in their buildings. If outdoor air quality is good, the building operator can use outside air to ventilate the buildings, but if the outdoor air quality is poor, the operator would shut the dampers that allow outside air into the building and turn on the air purifiers.  However, these air purifiers are expensive to run, and they are normally turned off. 
  • Increasing air circulation.  High levels of Carbon Dioxide (CO2) in a building are detrimental to the productivity and potentially the health of the building occupants. The primary source of CO2 in office buildings is the breathing of the building occupants, and one technique to mitigate this is to increase the level of air circulation in the buildings by increasing the speed of the fans in the Air Handling Units (AHU). Again, however, running these fans at higher than normal speed is expensive, so they are normally running at a normal speed.

In both these cases it is often a manual process to look at the IAQ dashboards and to manage the air purifiers or fans. This is where IoT technologies can make a big difference, monitoring the air quality and controlling the equipment. Look at this dashboard from the training facility of the International Union of Operating Engineers in Houston:





On the bottom, we see the current CO2 level, as pulled from the IAQ sensors by the ICONICS IoT software. In the middle, we see ‘Fresh Air Changes’. This is a calculated value, the volume of the served area divided by the air flow as pulled from the building management system (BMS) by the ICONICS software. By looking at the relationship of these two values, an operator can determine whether the level of CO2 might be improved by increasing the air flow.

That, of course is still a manual process, and can be improved by utilizing command and control features in IoT solutions. We would set an alarm or create a fault rule in the monitoring software to flag when the CO2 level is above some threshold (e.g. 700 ppm) for a certain amount of time (e.g. 5 minutes), and use that fault to push a command down to the BMS to increase the speed of the circulating fans thereby increasing fresh air changes. To make this more sophisticated, we would then have a second fault rule that triggered a command to reduce the speed of the fans to normal if the CO2 level returned to an acceptable level, or to issue an alert to Dynamics 365 Field Service for an operator to investigate the situation if the CO2 level remained high.

Finally, another variation on this theme is to monitor occupancy of the area and have a different CO2 threshold if the room is unoccupied. For this you would add an occupancy sensor and create a branch in your fault rule that used one threshold if the room was occupied, and another if it was not. Check out this ICONICS dashboard, from my house:




I am using a Delta O3 device that detects various environmental parameters as well as motion and sound levels, and I could use those signals mashed up with the CO2 to issue alerts. Unfortunately I don’t have the ability to write to my home HVAC unit to increase the fan speed (yet), but in commercial buildings this is commonplace.

While I can’t point you to documentation on this whole round-trip process, I’d recommend you look at two IoT whitepapers, the first on monitoring IAQ, the second and third on sending commands back to IoT devices with writable controls:

To summarize, though the first step in managing the environment is to monitor it, you need to act upon the findings. And IoT solutions make it possible to do this in a smart and effective way.


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