Share thisThe greatest single approach for reducing energy use in vivariums is to reduce or vary the room air change rates.
In the last few years, the concerns about global warming and the interest in reducing an organization's carbon footprint have increased significantly, as well as concerns over the cost of energy and the increasing volatility of energy prices. For most organizations, facilities have the greatest impact on carbon emissions and energy expenditures and as such have been receiving increasing scrutiny with regard to reducing energy usage. For organizations such as universities, pharmaceutical companies, and other life sciences organizations, labs and even more so vivariums are at the top of the list regarding energy usage. A recurrent theme from a recent conference on vivarium facilities was that the greatest single approach for reducing energy use in vivariums was to reduce or vary the room air change rates. Thus, the safe reduction or variation of air change rates in vivariums and also labs represents for most life sciences organizations the greatest single method for reducing their energy consumption and carbon footprint. Unfortunately, heretofore very little objective data has been available on the environmental and energy savings impact of both reducing and varying air change rates in labs and vivariums. This article attempts to address this data gap with the results of a major research study that generated a significant amount of objective data on the indoor environmental quality (IEQ) conditions of labs and vivariums that are using dynamic control of air change rates.
Before reviewing this study, it is important to first understand how air changes can be safely reduced in both labs and vivariums. One proven approach that was discussed in a previous article in ALN Magazine1 is by dynamically varying air change rates based on the air quality level or "air cleanliness" of the lab or animal rooms.
In a large majority of labs (particularly life sciences labs) and vivariums, the air flow is often dictated by the minimum air change rate for the space, which might be 12 to 20 ACH in a vivarium or 6 to 12 ACH in a lab room. Although high thermal loads or the heavy use of fume hoods or animal racks with heavy makeup requirements can sometimes drive the room airflow rates, oftentimes it is the minimum ventilation rate that determines the air flow. However, if the air in these rooms is "clean" or free of any harmful or irritating contaminants that the minimum air change rate is intended to dilute, then a high air change rate is not needed, at least for when the air is clean.
As such, one approach that has been shown to effectively and safely vary air change rates in labs and vivariums is to sense the quality of the air for such contaminants as volatile organic compounds (VOCs), ammonia, plus some other chemical vapors and odors, as well as particulates. When the room air is free of these contaminants, then the air change rate in the vivarium can be reduced to, for example, 6 ACH, or if it is a lab room to for example 4 or even 2 ACH.