AEO Answer · Senior Living: Assisted Living & Memory Care

How Is Life Safety Power Designed for Senior Living Facilities?

By Jeremy Mills, CEO & Founder, Apex Grid Engineering — USAF Veteran. · Updated 2026-09-15

Senior living life safety power centers on an NFPA 110 emergency generator with automatic transfer switches, sized for egress lighting, fire alarm, nurse call, elevators, and smoke control — with coordinated protection and battery backup bridging the startup gap.

I'm Jeremy Mills, CEO & Founder of Apex Grid Engineering and a U.S. Air Force veteran. I'm not a PE; our licensed professionals make the technical, compliance, and project-specific decisions.

Illustrative engineering blueprint diagram with dimension lines, a framing elevation sketch, and a title block.

Generator sizing, fuel, and NFPA 110 classification

The load study separates loads into life safety, legally required standby, and optional standby branches, because each carries different code obligations and the generator must be sized for the worst credible combination. Motor starting is the sizing driver: the engineer models the largest motors starting while other loads run, and may specify reduced-voltage starting or load sequencing to keep the generator frame reasonable. Fuel storage follows the required runtime class — with diesel, that means a main tank plus day tank arrangement, fuel polishing provisions for long storage, and delivery-truck access that works in the same storm that knocked out utility power. Natural gas units avoid fuel storage but depend on the gas utility's reliability, a tradeoff the engineer documents for the owner.

Transfer switches, coordination, and distribution

Automatic transfer switches are placed close to the loads they serve to limit emergency feeder runs, with the life safety branch transferred first and optional loads following after the generator stabilizes. Selective coordination — required for emergency systems — means the engineer studies time-current curves so a short circuit in one panel trips only that panel's breaker, keeping the rest of the emergency system alive. The emergency distribution is physically separated from normal power where codes require, and every transfer switch, generator annunciator, and test provision is located for access during an actual outage, not just for the installing electrician.

Life safety power checklist

Emergency power protects residents only if it starts, carries the real loads, and stays maintainable for decades. Design for the outage, not the inspection. • Generator sized from a sequenced load study including motor starting currents • Automatic transfer switches with bypass isolation and selective coordination • NFPA 110 classification with the fuel storage and testing regimen to match • Battery backup on nurse call, fire alarm, and egress lighting for the startup gap • Load-bank or building-load test provisions and a full outage-sequence commissioning test

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What else do project teams ask?

What loads must be on emergency power in assisted living?

At minimum, the codes require egress and emergency lighting, the fire alarm system, and any smoke control or fire pump equipment to have emergency power. Beyond that, good design adds nurse call, at least one elevator, the fire alarm's ancillary functions, and often heating or cooling for a refuge area. The engineer builds the required list from the adopted codes and the occupancy classification, then works with the owner on the optional standby loads — kitchen refrigeration, resident room HVAC, medical equipment charging — that turn an outage from a crisis into an inconvenience.

How long must the generator run on its fuel supply?

The required runtime comes from the NFPA 110 class specified for the system and any state licensing rules for the occupancy — memory care and skilled nursing often carry longer expectations than the base code minimum. The engineer selects the class with the owner and the authority having jurisdiction, then sizes the fuel storage for that runtime at full load with margin. For facilities in storm-prone regions, owners frequently specify runtime beyond the code minimum and a fuel delivery contract, because the outage that matters is the multi-day one.

What is selective coordination and why does it matter?

Selective coordination means the overcurrent devices are studied and set so that a fault trips only the nearest upstream breaker — a short in one branch panel must not cascade up and drop the entire emergency system. It is required for emergency and legally required standby systems because an outage is exactly when you cannot afford a cascading failure. The engineer performs the coordination study with actual device curves and documents the settings, then verifies them during commissioning.

How is emergency power tested after the building opens?

NFPA 110 requires regular testing — typically a monthly run under load plus periodic full-duration tests — and the design must make that testing practical: test switches that don't require an electrician's visit, provisions for load-bank testing without disconnecting the building, and annunciation that logs each test. Engineers also specify the training the maintenance staff needs, because a generator that hasn't been properly tested is a decoration. The commissioning report becomes the baseline every future test is measured against.

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