Self-contained emergency lighting works for small buildings. For hospitals, malls, transit hubs, and high-rises, central battery systems (CBS) take over. One bank of batteries, dedicated emergency circuits, scheduled testing, and lifecycle cost half of distributed fixtures.
Four ideas to carry into the next specification conversation you have.
On mains failure, the CBS inverter takes over and feeds 230 VAC to dedicated emergency-circuit fixtures, same fixtures, just on a different feed.
VRLA: cheap, 5–7 year life. LiFePO4: 3–4× cost, 12–15 year life, lighter, smaller footprint. Premium spec is shifting.
Hospital corridor at 5 lux for 180 min has a different kWh requirement than mall escape at 1 lux for 60 min. Size the battery for the duty profile.
Maintained = fixture lit normally, stays on during emergency. Non-maintained = off normally, ignites only on emergency. Both supplied by CBS.
Per EN 50171 (central power supply systems) and IEC 60598-2-22.
| Topology | Capacity · battery | Best fit |
|---|---|---|
| Self-contained per fixture | ≤ 5 W per fixture · 1.5–4 Ah NiMH | Offices ≤ 50 fixtures |
| CBS, small (LPS) | ≤ 500 W output · 24 V VRLA | Schools · small clinics |
| CBS, medium | 1.5–5 kW · 110 V or 220 V VRLA | Hospitals (one wing) · mid-rise |
| CBS, large | 5–25 kW · 220 V VRLA or LiFePO4 | Malls · transit · airports |
| CBS, campus | 25–250 kW · multi-string LiFePO4 | Hospital campuses · stadia |
| Hybrid CBS + generator | Battery for first 30 min, gen backup | High-rise (180+ min duty) |
Five reasons large buildings move to central battery systems.
Self-contained fixtures need every battery replaced every 4–5 years. A 600-fixture office at 70 SAR per battery = 42,000 SAR every 4 years, plus labour. CBS replaces one bank every 6–8 years, typically 30–50% lower lifecycle cost above 200 fixtures.
A CBS includes a monitoring panel that reports test state for the whole emergency network in real time. Compare with running monthly self-test rounds on 600 individual fixtures, each requiring visual inspection of a status LED.
VRLA batteries lose 50% life every 10 °C above 25 °C. In Saudi MV rooms reaching 35–40 °C, battery life can drop to half rated. CBS battery rooms must be air-conditioned to 20–25 °C, and the AC must run on emergency feed itself, otherwise the failure cascades.
The same as self-contained, but with a single test panel managing the whole emergency network. The annual full-duration discharge actually exercises the battery, preventing the sulphation cycle that degrades unused VRLA.
Lithium iron phosphate batteries do not vent gases, do not require cooling rooms, and last 12+ years even in 40 °C ambient. The upfront cost is 3–4× VRLA, but lifecycle and footprint savings make it the new spec for NEOM, RSG, and major Saudi hospital builds.
Our CBS solutions cover EN 50171 self-test, hot-swap LiFePO4 strings, BAS integration via Modbus or BACnet, and KSA Civil Defense documentation.
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