David Stymiest, PE CHFM FASHE, DStymiest@ssr-inc.com
The author has used load profiling to determine EPSS peak demand load for more than 20 years. The discussion below is intended to highlight some of the lessons learned. For a full discussion, refer to the author’s 2009 ASHE Management Monograph, “Managing Hospital Emergency Power Systems – Testing, Operation, Maintenance and Power Failure Planning” available at http://www.ashe.org/.
The author has used load profiling to determine EPSS peak demand load for more than 20 years. The discussion below is intended to highlight some of the lessons learned. For a full discussion, refer to the author’s 2009 ASHE Management Monograph, “Managing Hospital Emergency Power Systems – Testing, Operation, Maintenance and Power Failure Planning” available at http://www.ashe.org/.
NFPA Disclaimer: Although the author is Chair of the NFPA Technical Committee on Emergency Power Supplies, which is responsible for NFPA 110 and 111, the views and opinions expressed in this message are purely those of the author and shall not be considered the official position of NFPA or any of its Technical Committees and shall not be considered to be, nor be relied upon as, a Formal Interpretation. Readers are encouraged to refer to the entire text of all referenced documents. NFPA members can obtain NFPA staff interpretations at www.nfpa.org.
Hospitals should document their actual EPSS peak demand load. It is not enough to assume that the highest emergency generator kilowatt (kW) demand during an early-morning monthly test represents the true peak EPSS demand load. This is a poor assumption due to the variability of mechanical, building, and clinical process loads during a typical hospital workday. If an EPSS test time is chosen due to low clinical activity, then that avoided clinical load will not be reflected in the EPSS test loading. Additionally, some equipment, such as smoke control systems and fire pumps, will not operate except during atypical situations.
