Satisfying NFPA 110 and NEC requirements

Consulting engineers who specify emergency power equipment should identify when installations are required to comply with NFPA 110 in conjunction with other codes. This collection of case studies provides examples of recent projects that had various challenges associated with these requirements.

By Richard Vedvik, IMEG Corp. December 6, 2017

Learning objectives:

  • Learn about the core codes and standards that define how electrical engineers will design health care facilities.
  • Review examples of how to design standby and emergency power systems.
  • Analyze best practices to design for additional capacity and modern code compliance.

Designers commonly encounter existing facilities in need of emergency power system upgrades or additions. This article offers four case studies where the NFPA 99: Health Care Facilities Code identified the need for an emergency power system that required the engineering team to provide an increase in standby capacity while identifying opportunities for system improvements.

NFPA 110: Standard for Emergency and Standby Power Systems identifies requirements for the design, installation, and testing of standby power systems. The tables in the 2016 edition of NFPA 110 identify minimum runtime (class) and power restoration time (type) for these systems. On-site fuel storage for each site varied between existing or new, and each satisfied the Facility Guidelines Institute (FGI) guidelines for health care facilities for a minimum of 24 hours of runtime. The actual runtime for each case study varies based on local requirements and site classifications, as noted in 2016 NFPA 110 Annex A 4.2.

In 2016, the Centers for Medicare & Medicaid Services (CMS) adopted the 2012 editions of NFPA 99 and NFPA 101. The 2012 editions of NFPA 99 and NFPA 101: Life Safety Code reference the 2010 edition of NFPA 110. Chapter 4 of 2010 NFPA 110 defines the classification of emergency power supply systems (EPSS). NFPA 110 also defines the classifications of emergency power systems (EPS).

To simplify the difference, EPS are components that produce electricity and EPSS are components that distribute electricity from the EPS.  EPSS components include paralleling gear, transfer switches, distribution panels, and panelboards.   

The projects described below were in construction prior to the CMS adoption of 2012 edition of NFPA 101 and 2012 edition of NFPA 99. These projects were under the 1999 edition of NFPA 110 and 2000 edition of NFPA 101 for state licensing and had co-compliance with 2010 NFPA 110 for local jurisdictions. However, to provide an up-to-date discussion, the references to NFPA 110 in this article are to the 2016 edition, unless otherwise noted.

When existing emergency power systems are updated or replaced, the design engineer must review impacts to the existing distribution while planning for future expansion. Designing system upgrades goes beyond the final configuration and the engineer determine solutions that overcome implementation challenges. This article focused on four case studies in which existing health care campuses were in need of both additional capacity and modern code compliance. Each project is an example of how the design team communicated with the facility and construction team to identify needs and wishes and evaluated the existing system for opportunities for cost-effective corrections to existing conditions and future capacity.


Richard Vedvik is senior electrical engineer and acoustics engineer at IMEG Corp. He is a member of the Consulting-Specifying Engineer editorial advisory board.