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Essential Electrical Systems in Healthcare Facilities

Updated: May 8, 2023

Healthcare facilities (i.e., hospitals, ambulatory surgical centers, clinics, medical office buildings, etc.) can entail complex electrical designs, yet many become even more complex when deciding which backup system should be used - essential or emergency. Many designers feel that the word “healthcare” automatically insinuates the essential system is required. This system is comprised of three branches: life safety, critical, and the equipment branches. Similarly, the emergency system is comprised of three branches: emergency, legally required standby, and the optional standby branches.

Perhaps the most convincing evidence to use the essential system with all healthcare facilities is the National Electrical Code (NEC), section 517, which is entitled “Healthcare Facilities”. Although labeled in this manner, further investigation within this section is required to know which backup system should be employed.

When using the NEC, the first step is to look at the Health Care Facilities definition in Article 517 (Reference NEC Handbook 2020). The commentary mentions, “The term healthcare facility should not be confused with the term health care occupancy. All health care occupancies, including ambulatory health care occupancies, are considered health care facilities; however, not all health care facilities are considered health care occupancies. A medical office building can be a medical facility, but under NFPA 101 it typically would be a business occupancy.”

The key word here is occupancy, and this is identified in NFPA 101 and in the International Building Code (IBC). The architect determines the occupancy classification of the building. Different buildings, based on their use, have varying occupancy types such as business, storage, mercantile, institutional, and so on. Hospitals, which are used on a 24-hour basis, typically have an institutional (I-2) occupancy which automatically means they should have an essential system. But what about a medical office building, clinic, or ambulatory surgical center (ASC) which has a business (B) occupancy. Does that mean these buildings do not require an essential system?

To determine this question requires a second step which is to establish what category the healthcare facility falls under. There are four categories (NFPA 99 Definitions):

  • Category 1 (Critical Care) – failure of equipment is likely to cause major injury or death to patients, staff, or visitors.

  • Category 2 (General Care) – failure of equipment is likely to cause minor injury to patients, staff, or visitors.

  • Category 3 (Basic Care) – failure of equipment is not likely to cause injury…. but can cause patient discomfort.

  • Category 4 (Support Space) – failure of equipment is not likely to have a physical impact on patient care.

  • The facility’s healthcare governing body is responsible for defining what category the healthcare facility falls under not the engineer or architect. These categories truly determine if an essential system is required. Per NEC 517.29, an essential system is required for a Category 1 space and permitted to serve Categories 2, 3 and 4 spaces. NFPA 99 varies slightly in that the essential system is required for Categories 1 and 2 spaces but not required for Categories 3 and 4 spaces. Thus, health care facilities designated as Categories 3 and 4, can be connected to the essential system but if not present can use the emergency system.

Knowing the difference between when to use the emergency or essential system can significantly reduce or add costs to a building. For instance, in renovations where there is an existing building with multi-use occupancy, and a new healthcare facility tenant desires to lease a space, some engineers take the approach that the essential system is needed. If the existing multi-use building does not have the essential system and the new tenant has a category 1 or 2 facility, then yes, the essential system must be provided along with other measures (i.e., ground fault protection at the main service depending on voltage and amperage and additional ground fault protection for all the feeders in the main switchboard). These are cost drivers the new tenant and building owner need to know in the beginning.

Let's say the healthcare facility is a category 3 or 4 space and the existing multi-use building has an emergency system. Depending on the building’s characteristics (i.e., no smoke control system, a low-rise facility, and no specific owner equipment needing backup), the emergency system may be all that is required and need only emergency lighting and fire alarm backup which can be accomplished with batteries. If the engineer designs an essential system when it is not needed, the overall costs have increased without there being a code-required need. If the GFI protection is added to the main electrical switchgear, then there will be service interruptions, potentially angry tenants for loss of power, and possible revenue loss for the building owner. As one can see, there is a greater burden on the existing tenants, new tenant, and the building owner all because the engineer didn’t understand how to determine the correct backup system needed.

When designing healthcare facilities, the goal is to not only know what the codes say that govern designs but also how to interpret them correctly to alleviate the owner of any unnecessary costs and the engineering team of unneeded design. Alternatively, correct code application can advise an owner of added costs that are necessary for a healthcare facility. As mentioned earlier, find the occupancy type and category of each facility to determine if the essential or emergency system is required. Remember that the architect decides the health care facilities’ occupancy type and the healthcare governing body dictates what category any healthcare facility falls under. When armed with this information, it will give the engineer what she needs to determine if the normal power should be backed up by essential or emergency power.

Written by:

F&T Staff


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