Reducing Campus Air Change Rates Safely—An Authority Having Jurisdiction and Environmental Health and Safety Approach

Shannon Horn, P.E., University of Colorado Boulder
Timothy Lockhart, University of Colorado Boulder

The University of Colorado Boulder (CU Boulder) has approximately 2.1 million square feet of laboratory space, using approximately 43 percent of the annual energy consumption of the entire campus. All laboratories were built in different eras with different philosophies and standards regarding air change rates (ACH) and safety. CU Boulder authorities having jurisdiction (AHJ) and environmental health and safety (EH&S) departments were challenged with determining what ACH would be acceptable for the campus that minimized energy consumption while maintaining a safe laboratory environment, and how this approach could be pragmatically applied to new and existing facilities using limited resources.

The departments reviewed codes and industry standards that the university and the state of Colorado have adopted. The review determined there is no prescribed ACH that determines a safe laboratory. The departments determined pragmatically that there are three main drivers for ACH in laboratories: loads, hood ventilation, and hazard type of laboratory activities. Loads were determined by surveying all the loads in a space, metering a sample of typical laboratories throughout the campus, determining a diversity value based on the metered data to surveyed data relationship and included envelope loads, and benchmarking this information with the Labs21 Energy Benchmarking Tool. Hood ventilation needs were determined by reviewing hood face velocities, and evaluated if re-balancing, modifying/changing the hood to a high-performance fume hood changed the ACH enough to justify the activity. Hazard classifications were based on the National Fire Protection Association guidelines and laboratory activities. Hazard activities were categorized as either high (six ACH) or low (four ACH) hazard. Comparing all three variables, CU Boulder could determine which variable was driving the laboratory ACH, and, correspondingly, which ACH reduction methodology would be best to pursue. Three main methods to reducing ACH were determined from this analysis: re-balance the system, modify/replace hoods, or modify major infrastructure.  

Applying the above approach to an existing facility resulted in a project that rebalanced a laboratory building from 10 to 64 ACH down to four to six ACH and solved long-term complaints of temperature and maintenance backlog. The project also verified the assumptions and extrapolations that went into the load and hazard evaluations and justified itself with a seven-month payback.

This unique, pragmatic approach will result in substantial energy savings, while maintaining safe laboratories. The above case study verified the assumptions that went into the loads and hazard analysis of the evaluation. Applying this approach campus-wide, CU Boulder estimates an approximate 25 percent average energy reduction for the laboratories.  

Biographies:

Shannon Horn is a professional engineer and LEED AP, with a Bachelor of Science degree from Colorado State University. Ms. Horn is a campus mechanical engineer for CU Boulder, where she holds a diversity of responsibilities from commissioning agent to AHJ to supporting energy conservation projects and initiatives campus-wide. Ms. Horn has more than seven years experience as a consulting engineer for a diversity of clients that primarily focused on industrial, laboratories, data centers, institutional, high-tech, and educational facilities. Ms. Horn has nine years of experience working as a facilities engineer for a semi-conductor/inkjet facility and a higher education learning institute. Regardless of position or job title, Ms. Horn's objective and passion have been oriented towards high-technology environments and how to reduce energy without compromising form, fit, or function.

Timothy Lockhart is a certified industrial hygienist and certified hazardous materials manager with a Bachelor of Science in environmental chemistry and toxicology and a Masters of Science in industrial hygiene from the University of Massachusetts, Amherst. Currently employed as an industrial hygienist for CU Boulder, Mr. Lockhart is responsible for a variety of programs, ranging from indoor air quality to employee exposure assessments, hazardous exhaust ventilation, and employee trainings. Prior to joining the EH&S team at CU Boulder, Mr. Lockhart was a consulting industrial hygienist for seven years and helped manage health and safety risks for various industrial and corporate clients. As a consultant, Mr. Lockhart developed and implemented EH&S programs and corresponding audits, conducted indoor air quality investigations, and implemented various strategies to help protect worker health and safety. Mr. Lockhart's understanding of federal and state regulations and current technology has allowed him to provide cost savings for clients, while ensuring sound health and safety solutions.