Laboratories, vivariums, and cleanrooms consume significantly more energy than conventional buildings due to the ventilation requirements needed to support safety, compliance, and operational performance. As organizations look to improve efficiency and resiliency, demand control ventilation (DCV) has gained traction as a strategy to reduce energy use without compromising critical environmental conditions.
However, successful deployment in these spaces requires more than simply installing sensors or adjusting airflow rates. Based on decades of experience deploying airflow optimization programs in critical environments, three factors consistently determine whether DCV systems deliver reliable long-term performance.
1. Proper engineering and risk assessment analysis
Successful airflow optimization begins with proper engineering and a thorough risk assessment. Not all spaces within a critical environment operate under the same requirements, and each room carries different operational and compliance considerations. This applies to all types of critical environments.
Before implementing demand control strategies, organizations must understand both the original design conditions and the current operating conditions of the facility. They must also evaluate how those conditions may change once demand-based ventilation is applied.
Common issues encountered during deployment include:
- Failure to evaluate lifecycle costs and lifecycle risk
- Limited understanding of airflow equipment turndown capability and minimum and maximum airflow performance
- Lack of a formal risk assessment reviewed and approved by environmental health and safety, quality, or animal care teams.
Proper engineering ensures that demand control strategies are applied only where they support the operational, safety, and compliance requirements of the facility and/or where IAQ insight is valuable.
Once the engineering is completed, it is paramount to deploy a properly integrated and operating DCV system that will work over the life of the facility in concert with the BMS & lab/space control systems.
Best practice: Assessment and deployment of DCV in critical environments should be done by experienced professionals and in conjunction with EH&S, quality, and/or animal care constituents.
2. Accurate measurement / proper and lasting control
The primary and fundamental function of a DCV system is to measure key indoor air quality parameters and then convert those measurements into ventilation control signals for the laboratory or building management control system. For this to work, reliable and consistent control depends on accurate IAQ measurement. Simply put, bad and/or inaccurate data in will provide bad control out and thus sacrifice safety and compliance.
This means that sensor accuracy is critically important. Unfortunately, sensor accuracy has also long been a challenge in the built environment. Independent studies abound, including work conducted by Iowa State University, which has consistently shown that many sensors installed in buildings are not properly calibrated prior to installation and are rarely recalibrated according to recognized NIST standards after deployment.
A common mistake is evaluating DCV solutions primarily on initial cost rather than lifecycle performance, maintainability, and long-term reliability. While this approach may be acceptable for some equipment decisions—although the saying “you get what you pay for” still applies—it cannot apply to a DCV system that supports environments where research outcomes, human health, animal welfare, and product quality depend on the reliable airflow operation. In critical environments, accurate measurement is fundamental to overall system performance, and a lifecycle cost and performance assurance analysis must be conducted.
Researchers working in these facilities rely on properly calibrated instruments, such as gas chromatographs and mass spectrometers, and therefore expect the same level of accuracy from the systems responsible for maintaining their health and safety.
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Lessons learned: Measurement strategy is particularly important in facilities operating with 100 percent outside air systems. The measurement approach must confirm that changes in internal conditions are being generated from within the space itself and not from the air distribution system. Thus, you avoid bringing in more “bad” air.
Best practices:
- Ensure NIST traceability of sensors both initially and when calibrated
- Test sensors more than just upon initial deployment, especially if regular calibration is not being done, or being done at long intervals i.e., greater than six months
- Using differential measurement DCV signal that compares room air to outside air with the same sensor to avoid stacking errors and improperly increasing room air with contaminated outside air.
Using separate sensors for outside air and room measurements often introduces calibration drift between the two devices. Differential measurement from the same sensor helps maintain accuracy over time and provides more reliable data for ventilation control.
Ask for NIST traceable certificates. This ensures a verifiable calibration standard, providing the accountability needed to keep DCV systems performing reliably over time. Look to work with a provider who supports a 100 percent performance guarantee. Most will only do this if the sensor is properly calibrated and maintained. However, it also ensures it’s being done as specified and required.
3. Proper integration and deployment
Proper system integration determines whether DCV operates reliably over the life of the building.
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DCV systems have now been deployed in critical environments for well over 15 years and in thousands of facilities worldwide. Experience from these installations has shown what works and what frequently leads to problems.
While value engineering can quickly become devalue engineering, owners, and particularly their various constituents, are most impacted by proper or improper deployment of a DCV system. Thus, it is paramount to have all parties in these conversations and to ensure that total lifecycle cost is considered. What can appear economical at first often leads to systems that are expensive to maintain, integrate, or program, which can lead to systems being fully disconnected.
Following #1 and #2 above, once a room’s air quality measurements are obtained, they must be converted into a ventilation control signal to either raise or lower airflow. This raises several practical questions:
- Who performs the calculations that translate air quality data into airflow control signals?
- How are control thresholds determined?
- How is system performance verified during commissioning?
- How is accuracy maintained over time?
Successful deployments address these questions through engineered system design and documented integration with the building management system.
Effective DCV systems typically include:
- Engineering input and risk assessment with participation from Environmental Health and Safety and other compliance teams
- Industrial-grade sensors with documented calibration procedures
- System-level calculation of ventilation control signals delivered directly to the building control system.
Providing calculated DCV control signals is far more reliable than sending raw air quality values and expecting building automation technicians to interpret them within the control system.
Lesson learned: Commissioning is key. Assuming you have accurate measurement, the system performance will ultimately depend on how these signals are integrated into the building automation or lab control system. A common mistake during new construction is lack of commissioning of these systems, which then lets contractors and/or equipment suppliers off the hook and puts ownership back on facilities and EH&S, most often left with an inoperable system.
Even well-designed systems will lose performance over time as sequences are modified, equipment degrades, spaces change use, and overrides are introduced. Without ongoing visibility and periodic optimization, facilities drift away from intended performance.
Best practice: DCV commands should be generated by DCV system and not via raw data interpretation of a BMS technician. This is a very important point. BMS technicians may not always be familiar with how to interpret raw IAQ sensor data or configure key parameters. The BMS/BAS industry faces persistent workforce shortages and relies heavily on technician-specific operational knowledge, making knowledge transfer and continuity significant challenges. In the end, having a system that delivers the full end-to-end responsibility of providing accurate and repeatable DCV signals is a must.
Conclusion
DCV can improve efficiency and operational visibility in laboratories, vivariums, and cleanrooms, but only when implemented with the facility’s safety, compliance, and performance requirements in mind. Successful programs depend on three fundamentals: proper engineering and risk assessment, accurate and reliable measurement, and strong system integration that can be maintained over the life of the building.
