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What to Measure and Why?

Posted by: IotaComm

How Next-Generation IoT Sensors
Deliver Exponential Building Intelligence

Technical considerations for installing your IoT sensor network are critical, but this is just the first half of the implementation journey. Once you have your new IoT sensors and gateways up and running – it’s imperative to correctly set all of the various sensor parameters and develop response protocols, checklists, and lines of responsibility for addressing alarms, variations and outliers.

As our technical infrastructure grows more complex and integrated, the role and importance of accurate sensor readings is growing in importance. Just recently, civilian astronauts onboard a SpaceX flight couldn’t disengage a cockpit alarm. Fortunately, instead of signaling a severe malfunction in the spacecraft, it turned out that there was a faulty sensor in the onboard toilet! Here on earth, drivers are very familiar with sensor warning lights going off on their dashboard for no apparent reason – and most of us have had smoke detectors that signal a false alarm at random times of the day or night.

For building managers, avoiding these types of sensor errors is a top priority. That begins with a careful understanding of sensor parameters and learning the acceptable measurement ranges for each type. As the IoT environment grows more robust and numerous battery-powered LPWAN sensors are deployed, building managers must begin taking a holistic view of their sensor data – learning to map indoor environmental conditions over time and in a granular fashion.

Gaining a holistic view of building data unlocks new opportunities for improving your buildings’ sustainability, health, and safety. The benefit of a robust array of data points is that it allows for a dynamic understanding building health – not as a static snapshot but as a constantly evolving and changing, living system. This holistic, dynamic view delivers granular data from multiple sources – and within this context, it’s important to highlight the details for each sensor reading. While there are dozens of different building factors that can be measured – the following sensor data measurements serve as the core elements for most IoT installations.

1). Temperature

Temperature is a key measurement for indoor environments and one that we are all familiar with. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends maintaining a range from 68.5º F to 75º F (20º C – 24º C) in the winter, and from 75º F to 80.5º F (24º C – 27º C ) in the summer. The difference in temperature ranges between the seasons is largely due to clothing selection.

When you install multiple temperature sensors across your facility, you will achieve a new level of granularity of data and control. If you have modern vent controls built into your HVAC system, room-by-room temperature adjustments are possible over the course of days and seasons. If you have an older building – holistic temperature readings help identify hidden hot spots or cold spots where you may need to provide specific remediation.

As you begin to track temperature fluctuations over time, HVAC systems with programmable thermostats or building automation systems can be “set back” during unoccupied periods. Compared with binary “ON – OFF” approaches to cooling and heating, this “set back” method still provides significant energy savings, but it does not require the system to work as hard to bring the indoor conditions back to desired set-points.

2). Humidity

Humidity is closely related to temperature in terms of impacting overall comfort levels and indoor air quality. Low levels of humidity can lead to dry skin, while high levels of humidity can lead to mold, mildew, and even structural damage to building elements. ASHRAE recommends that indoor relative humidity be maintained at or below 65%, while the EPA recommends maintaining indoor relative humidity between 30 and 60% to reduce mold growth. Like temperature readings, having a robust array of humidity data points over time provides a more accurate and dynamic view of your overall indoor air quality.

3). Leak Detection

Humidity is a measurement of moisture in the air, but water leaks can be even more damaging if left undetected. IoT sensors can be placed around a variety of “at risk” areas for water leaks such as refrigeration units, AC units, basements and pipes. Modern LPWAN leak sensors can be deployed in places where typical wired sensors are impractical and run for years on just batteries.

4). CO2

CO2 is typically used as a proxy for building occupancy. We have all sat in crowded classrooms or meetings where it feels like “the air has been sucked out of the room”. CO2 sensors can show which rooms are problem spots for this type of highly congested usage. Capturing and viewing CO2 readings in a time series can also help identify areas with steady traffic within the building – but are not necessarily “high occupancy” at any single point in time. These high traffic areas can also see a buildup of unacceptable CO2 levels.

If the building is equipped with modern HVAC controls, then louvers and airflow can be adjusted to address rises in CO2, while in older buildings – windows can be opened at specific periods in the day when there is a consistently high reading of CO2.

CO2 levels can significantly affect the productivity of building occupants, especially as levels rise above 1,000 ppm. Here is the impact of CO2 at specific levels.

CO2 parts per million Impact on Occupants
250-400ppm Normal background concentration in outdoor ambient air
400-1,000ppm Concentrations typical of occupied indoor spaces with good air exchange.
1,000-2,000ppm Complaints about drowsiness and poor air.
1,000-5,000 ppm Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
> 5,000 ppm Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppm Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.

In terms of assessing an overall risk for airborne diseases – CO2 measurements can be combined with other data points such as humidity, airflow and occupancy to generate an indexed “risk score” for the entire building in terms of air quality and disease risk.

5) Volatile Organic Compounds (VOCs)

In many newer buildings, you might have experienced that “new carpet smell” – but even after the smell is gone, harmful Volatile Organic Compounds (VOCs) may still be in the air. Ironically, as people work to clean surfaces during the pandemic, they may inadvertently introduce high levels of harmful VOCs into the indoor air environment. There are many thousands of different VOCs, but some of the more prevalent and potentially harmful ones include benzene, formaldehyde, ethylene glycol, methylene chloride, tetrachloroethylene, and toluene. VOC sensors can detect these specific compounds and provide alerts if thresholds have been triggered. Because there are so many organic compounds, “Total VOC” sensors have been created that track a broader range of 20 or even 30 contaminants. These TVOC sensors provide an essential complement to specific VOC monitoring.

6). Air Pressure

Typically, we think of air pressure when tracking the weather, but indoor air pressure can have a significant impact on indoor environments as well. Identifying differences in air pressure between spaces can help efficiently move air from high-pressure areas of the building to low-pressure areas. Air pressure also plays an important role in maintaining cleanrooms for high-tech and healthcare settings.

7). Light

A study conducted by the American Society of Interior Design indicated that 68 percent of employees complain about the lighting situation in their offices. While natural lighting has many positive benefits – not every room or space can rely on natural lighting. As building usage and outdoor lighting change during the day, sensors can adjust lighting levels along a light continuum rather than just a simple binary on-off setting. In fact, studies have found a strong correlation between types of lighting and different levels of productivity with warmer levels of lighting promoting relaxation while cooler lighting promotes brainstorming and productivity.

 8). Occupancy Sensing

Occupancy sensors rely on motion detection to provide insight into how all of your spaces are being used. Whether it’s a school, office building, campus, shopping mall, airport etc., you can get access to the real-time data you need to better manage your spaces, reduce energy and maintenance costs and enhance occupants’ health and comfort. More than simply counting the number of people present in a given space, occupancy sensors can trigger automatic responses in buildings to comply with codes – turning lights off in unoccupied spaces to save energy or automatically adjusting temperature or ventilation setting in the HVAC system. By providing this level of cross-system integration and response, occupancy sensors play an important role in orchestrating your overall IoT system performance.

Occupancy sensing capabilities include:

  • Counting people entering or exiting any space throughout each floor to ensure safe distancing practices and regular sanitation
  • Collecting data on the number of people using specific areas of your building
  • Significantly reducing energy costs and carbon footprint with Smart HVAC and lighting control based on occupancy behavior
  • Pinpointing over and under-utilized areas to streamline janitorial services
  • Identifying where people are located in the event of an emergency such as a fire, intrusion, safety threats etc.


Driven by breakthroughs in sensor design and LPWAN networking, IoT systems are growing more robust and cost-effective. This increasing sophistication means that building managers can now take a holistic view of their sensor data – mapping indoor environmental conditions over time and in a granular fashion. This data-rich view provides a new range of possibilities for tracking and controlling many different aspects of sensor-related parameters – and can make dramatic improvements to the overall sustainability, health, and safety of your facilities.

If you would like to schedule a demo of how IotaComm can help unlock the potential of next-generation IoT technologies and data, please contact us today!