Dissecting the Essential Electrical System (EES) in Healthcare Facilities
It's no secret that NFPA 70: National Electrical Code (NEC) is aimed at saving lives. There are requirements throughout the document that are specifically included to prevent shock and electrical fires. However, once in a while we need requirements to install the electrical system in a way that supports life saving efforts of a different kind. Sometimes, it is the electrical system itself that will end up saving a life and other times it might be key components of the electrical system that support certain life safety functions of a building.
One type of occupancy that illustrates this point is a hospital. Healthcare facilities are a great example of the NFPA Fire & Life Safety Ecosystem, a framework that identifies the components that must work together to minimize risk and help prevent loss, injuries, and death from fire, electrical and other hazards. These facilities are also prime examples of where the convergence of multiple building codes and standards can make it hard to digest and keep straight, especially when it comes to the essential electrical system (EES). The EES is a critical piece to the operation of healthcare facilities and instrumental in providing life safety in these occupancies. However, we need to take a look at all of the moving pieces to better understand how this supports the mission to save lives.
First, let's take a look at why we even have a need for the EES in the first place. In order to do this, we need to understand what makes up an EES. For our purposes here, we will focus on a Type 1 EES. But first we should define what an EES is. NFPA 99: Healthcare Facilities Code actually defines an EES as:
“A system comprised of alternate sources of power and all connected distribution systems and ancillary equipment, designed to ensure continuity of electrical power to designated areas and functions of a health care facility during disruption of normal power sources, and also to minimize disruption within the internal wiring system.”
Specifically, a Type 1 EES is made up of three separate branches that provide power to different functions within the facility:
- The first branch is the life safety branch and it is intended to deliver power to the systems that are needed for the purpose of life-safety, such as exit signs and egress lighting.
- The second branch is the critical branch. This branch contains circuits and equipment that are in certain areas and critical to the function of patient care within the facility. Critical circuits can supply items like task lighting, certain receptacles, and fixed equipment in Category 1 (critical) spaces.
- The third branch is the equipment branch. This branch powers systems that are integral to the building operation. Systems such as climate control HVAC and certain elevators can be found on this branch.
Just exactly how this system needs to perform is not exactly a function of the NEC. Remember, the purpose of the NEC is the practical safeguarding of people and property from electrical hazards. Keeping a hospital up and running in an emergency is certainly an important task, however, it belongs to another document, like NFPA 99. The role of the National Electrical Code is more about how to install the EES, both to meet the performance requirements of NFPA 99 and to be safe in alignment with the purpose of the NEC.
As I mentioned, in order to understand the full picture of just how the EES factors into the life saving mission of the Fire & Life Safety Ecosystem, we need to examine all of the pieces in this equation. To do this justice we will be taking a deeper look at the specifics of this system as they relate to the mission of making the world a safer place in a series of blogs over the coming weeks. Our next blog will examine the three different branches of a Type 1 EES the Life Safety Branch, the Critical Branch, and the Equipment Branch. We will cover what types of loads are allowed on each, how each branch is required to perform, and how exactly we install these systems to accomplish this. We'll also explore the nuances of the relationships between the NEC, NFPA 99, and NFPA 101, Life Safety Code . Make sure to stay tuned as we break down one of the more complicated and confusing areas in electrical installations.
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