Electrical Systems for Healthcare Facilities

Keeping the Power On

Utility companies go to great lengths to maintain reliable electrical systems, and in the United States, our power grid is more than 99 percent reliable. To compensate for our imperfect world, Article 517 of NFPA 70 – The National Electrical Code (NEC) requires an Essential Electrical System (EES) to provide power to critical medical loads when normal power is lost. The EES must have two or more sources of power, which can consist of the following:

• Utility power – This is usually the primary ‘normal’ source.
• Generators – This is the most commonly used secondary “alternate” source.
• Fuel Cell Systems.
• Energy Storage Systems such as batteries.
• A Health Care Microgrid.

Whatever the alternate power source, there must be transfer switches to safely and reliably transfer the power from one source to another and back.

Risk Categories

Paralleling the NFPA 99, Health Care Facilities Code, and Article 517 of the NEC, the various areas within healthcare facilities are divided into four separate risk categories. These categories range from Category 1, where a power failure can cause significant injury or death, to Category 4, where a power failure is unlikely to harm patient care.

Category 1 (Critical Care)

These areas are where patients receive invasive procedures and are connected to line-operated, patient care–related appliances such as:

• Critical care patient rooms
• Intensive care patient rooms
• Angiography laboratories
• Cardiac catheterization laboratories
• Delivery rooms
• Operating rooms
• Post-anesthesia care units
• Trauma rooms

Category 2 (General Care)

Spaces where electrical system failure is likely to cause minor injury to patients, staff, or visitors, such as:

• Inpatient bedrooms
• Dialysis rooms
• In-vitro fertilization rooms
• Procedural rooms
• Diagnostic imaging spaces

Category 3 (Basic Care)

Spaces where electrical system failure is not likely to cause injury to patients, staff, or visitors, but can cause patient discomfort, such as:

• Examination or treatment rooms in clinics, medical and dental offices, nursing homes, and limited care facilities

Category 4 (Support)

Spaces where electrical system failure is not likely to physically impact patient care include:

• Anesthesia workrooms
• Sterile supply
• Laboratories
• Morgues
• Waiting rooms
• Utility rooms
• Lounges

The EES is divided into three branches based on the abovementioned categories—life safety, critical, and equipment. Think of the life safety branch as the power that keeps people alive; the critical branch powers items essential for patient care; and the equipment branch as the power that helps keep the facility running. These three branches must be kept separate from the normal power and each other, so a healthcare facility must have additional panelboards and switchboards to distribute the power. Except for very small facilities, each branch of the EES requires at least one automatic transfer switch. The Branch Comparison Table shows how these branch circuits need to be separated.

• Life Safety Branch – The life safety branch is restricted to loads responsible for life safety. These consist of emergency egress lighting, exit signs, fire alarm system, and communication systems used for issuing instructions during emergency conditions.
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  Critical Branch – The critical branch is responsible for patient care equipment and loads. These consist of task illumination, fixed equipment and selected receptacles. Spaces that utilize anesthetizing gases, patient beds, medication preparation, pharmacy, treatment rooms, nurse call systems, telephone and data equipment, and selected power circuits needed for effective facility operation.

• Equipment Branch – The equipment branch is used for various other equipment loads that are required for facility operation. Equipment loads such as central suction systems, sump pumps, compressed air, HVAC equipment, kitchen hoods, and smoke control or stair pressurization.

Any healthcare facility with Category 1 spaces needs to have a Type 1 EES consisting of all three branches (Life Safety, Critical, and Equipment). A healthcare facility with only Category 2 or lower spaces, such as nursing homes or limited care facilities, would have a Type 2 EES that only needs two branches (Life Safety and Equipment).

However, if any area in a nursing home or limited care facility falls into Category 1, the EES must be a Type 1 system.

Related Codes and Standards

Architecture and engineering teams may discover they need more information throughout the design process. The following codes and standards are good sources to consult:

• NFPA 99 – Health Care Facilities Code
• NFPA 101 – Life Safety Code
• NFPA 110 – Standard For Emergency and Standby Power Systems
• FGI – Facility Guidelines Institute
  • Guidelines for Design and Construction of Hospitals
  • Guidelines for Design and Construction of Outpatient Facilities
  • Guidelines for Design and Construction of Residential Health, Care, and Support Facilities

When your team follows these code provisions and your facility’s systems are carefully maintained, its electrical system will be reliable, even when utility power is occasionally lost. With these systems in place, physicians can confidently perform their work. Ultimately, patients reap the benefits of modern medical science without ever having to think about, or be aware of, what could have made things difficult.