Laboratory Safety: Demand Control Ventilation Challenges and Opportunities

Apr 29th, 2018 | By | Category: Featured Articles

Laboratory ventilation is an important component of environmental, health, and safety (EHS) risk management and compliance at research universities and similar institutions. Traditionally, the practice in laboratories was to maximize air change rates (ACH), with an hourly ACH rate of 12 or more considered to be sufficient to protect worker safety. There are several limitations to the fixed flow approach to laboratory ventilation. For example, continually running ventilation equipment at a high ACH rate wastes money and energy during times when workers and chemical hazards are not present, but reducing the ACH during off-peak hours exposes staff who work during non-peak hours to higher levels of toxic chemicals. Also, the higher rate of air flow can cause a higher rate of evaporation in the event of a spill, resulting in higher personal exposures to the spilled chemical. Fortunately, new advances in Demand Control Ventilation (DCV) address many of the limitations of fixed flow ventilation.

 

How DCV Works

DCV systems seek to address the deficiencies inherent in fixed rate ventilation systems by balancing safety with energy efficiency. Air exchange rates are tied to real-time data so ventilation can be adjusted to meet actual laboratory conditions versus arbitrarily static ventilation levels. The centralized DCV system draws air packets from individual test areas and routes the air packets to a centralized sensor suite that analyzes each air packet for a variety of parameters. Smart signals transmitted from the sensor suite to the laboratory’s building management system can then be used to adjust the building’s ventilation controls. Data from the system are also presented through a dashboard that can be used by EHS professionals for a quick check of laboratory spaces or as the starting point for a deeper dive into laboratory conditions.

 

How DCV Data Can Support EHS

DCV can support EHS staff in many ways. For example, at one research university, an EHS professional using a DCV dashboard noticed that carbon dioxide (CO2) had been detected in a room at a concentration of more than 2,000 parts per million (ppm) for the past 24 hours. After a brief investigation, staff members discovered a faulty CO2 gas piping connection on a piece of equipment. The connection was fixed, the leak went away, and the CO2 concentrations returned to normal. By using the analytics to identify the leak as CO2, the university was able to save money associated with performing additional leak testing on all of their gas piping systems. Also, the data showed that the DCV system had responded to the increased CO2 concentrations and increased ventilation rates as designed.

In another example, at a laboratory in a leading research university in Philadelphia, the DCV system flagged a particular day of the week and time of day when chemical concentrations outside of the normal range were regularly occurring. The university’s EHS staff were able to use that data to identify a specific lab technician who was not following safe laboratory practices, the cause of the excess readings. They retrained the technician, which greatly reduced the employee’s exposure to hazardous chemicals.

 

Benefits and Challenges of DCV

As illustrated through the previous examples, DCV provides principal investigators (PIs), researchers, and EHS professionals with a real-time window into laboratory practices. With DCV, EHS personnel can measure the number and types of events, analyze where and when events occur, assess event duration, and gain insight into indications of cause. These data can then be accessed by PIs and other researchers, as well as the EHS team, to identify training or maintenance needs. Also, as noted previously, intelligent demand-based controls protect laboratory occupants with variable ACH and in so doing, also reduce the building’s energy use and energy cost.

There are some aspects of DCV that EHS staff should keep in mind. Although continuous data collection and reporting does identify opportunities to improve safe lab practices through interpretation of events and behaviors, demand-based platforms should not to be considered as a part of a laboratory’s threat detection system, because they do not detect and remove toxic airborne agents. Also, managers and staff should always remember that dilution ventilation is not a replacement for safe lab practices!

Finally, it is important to remember that not all labs are suited for DCV technology. In general, controlling ACH using DCV is a great fit for general research, vivaria, and wet chemistry labs. DCV is not a good fit for fume hood dense labs and those that deal primarily with agents that are potentially lethal or could cause high health risks, such as spaces rated as Biosafety Level 3. Anyone considering DCV should ensure that the solution is deployed with careful coordination between the facilities team, EHS, and experienced third-party professionals who specialize in the technology.

 

Smart Lab Case Study

The U.S. Department of Energy has adopted and is now promoting a Smart Lab concept pioneered by the University of California, Irvine (UCI). UCI, in collaboration with other universities, created a Lab Bench Top Risk Assessment-based ACH Decision Tree. The tool asks fairly simple questions such as:

  • Are there contaminants in use that are highly toxic by inhalation?
  • Is the contaminant a carcinogen or does it have exposure limits?

UCI used this tool to deploy demand-based control across more than 1,500 lab spaces on their campus. The decision tree found that approximately 86 percent of evaluated spaces qualified for demand-based control. This means that certain spaces may require much higher base-level ACH rates, and it is an owner’s decision to determine whether monitoring of indoor environmental quality should be done instead of demand-based control. In short, it remains critical to understand where hazardous materials exist and to train and promote safe lab practices when working under hoods with hazardous chemicals.

 

Conclusion

When deployed appropriately, DCV can help organizations receive the benefits of improved risk management, reduced energy usage, and substantial cost savings. The successes already achieved by many leading research institutions should be a testament to others who are considering adopting and deploying demand-based control. Less money spent, less energy used, more air supplied when needed, and insightful data provided to EHS staff and laboratory managers seem like a winning formula.

 

About the Author

Aircuity creates smart airside solutions through its intelligent building platform. These solutions significantly reduce energy costs and improve indoor environmental quality for occupants. As the demand control solution, Aircuity optimizes ventilation rates through its patented technology. As a result, commercial, institutional and lab building owners can lower operating costs, protect occupants and verifiably reduce energy use by as much as 60 percent. Founded in 2000 and headquartered in Newton, Massachusetts, Aircuity’s solutions have benefited more than 400 organizations such as Google, Amazon, Eli Lilly, Masdar City, the University of Pennsylvania, and the University of California, Irvine.

Photograph: Lab Work by Jean Scheijen.

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