Emergency lighting luminaires — operating mode and battery autonomy

The 560-emergency lighting guide covers the photometric requirements (illuminance in lux) and the emergency lighting self-test systems guide covers the periodic testing of a luminaire. This article covers a third layer: the construction requirements for the luminaire itself from NEN-EN 60598-2-22, including the operating mode and battery autonomy.

Operating mode

NEN-EN 60598-2-22 distinguishes, among others:

• Non-maintained: the emergency lamp only operates when the normal supply fails.
• Maintained: the lamp is permanently lit, serving as both normal lighting and — during a mains failure — emergency lighting.
• Combined non-maintained/maintained: the luminaire contains both a normal and a separate emergency light source.

Battery autonomy

The battery of a self-contained luminaire must be able to deliver a specified autonomy (rated duration) — in practice usually 1 hour or 3 hours, depending on the building type and the applicable local/national regulations (for example a longer autonomy for buildings with an elevated evacuation risk). This article does not give a universal Dutch standard value for which building category requires which autonomy class — that follows from the applicable building regulations/fire-safety requirements for the specific building.

Recharge period

After a full discharge (for example from the annual full-autonomy test, see the self-test systems guide), the battery must, within a specified recharge period — commonly taken in industry practice as a maximum of 24 hours — again have sufficient capacity to deliver the full rated duration.

Note: the exact recharge time and permitted cell chemistry follow from the specific product certification of the luminaire — this article gives the normative framework and the value common in industry practice, not a guaranteed universal value for every product.

Battery service life

Emergency lighting batteries have a finite service life; industry practice commonly assumes a design life of around four years, after which a battery must continue to be tested critically at intervals (or replaced) to ensure the full autonomy is still achieved — a battery that drops below roughly 80% of its original capacity can generally no longer reliably deliver the required autonomy.

Practical relevance

When replacing a faulty emergency lighting battery, it is not enough to fit "a battery that fits" — the replacement battery must support the same autonomy class and recharge characteristics as those the luminaire was originally certified for, otherwise the luminaire no longer meets its own product certification after replacement, despite looking and connecting identically.

Common mistakes

1. Fitting an unspecified replacement battery after a fault — without the correct capacity/cell chemistry the luminaire can no longer achieve the certified autonomy, even though the emergency lighting appears to function normally at first glance.
2. Assuming a "maintained" luminaire automatically meets emergency lighting requirements because it is always lit — the operating mode says nothing about whether the battery autonomy and the photometric requirements (see the 560 guide) have actually been verified.
3. Leaving a battery in service past its design life without a full autonomy test, on the assumption that "it has always worked so far" — capacity degradation often only becomes visible under a full discharge, not during a short function test.

Related

• Emergency & escape lighting (§560)
• Emergency lighting — automatic test systems (NEN-EN 62034)