Plan emergency lighting with clear engineering inputs quickly. Check lux targets, spacing, and fixture counts. Export results for audits, tenders, and safer buildings everywhere.
| Scenario | Area (m²) | Lux | UF | MF | Luminaire (lm) | Autonomy (h) | Result luminaires | Recommended Ah (12V) |
|---|---|---|---|---|---|---|---|---|
| Egress route estimate | 120 | 1.0 | 0.60 | 0.80 | 220 | 3 | 114 | ~174 |
| Open area, higher target | 250 | 2.0 | 0.65 | 0.75 | 350 | 1.5 | 205 | ~155 |
| Small corridor zone | 45 | 1.0 | 0.55 | 0.85 | 200 | 2 | 48 | ~62 |
1) Lumens required
Raw lumens = Area × Target luxAdjusted lumens = Raw lumens ÷ (UF × MF)Luminaires = ceil(Adjusted lumens ÷ Lumens per luminaire)2) Battery sizing
Total load (W) = Luminaires × Wattage per luminaireDC bus (W) = Total load ÷ Driver efficiencyRequired Wh = (DC bus × Autonomy) ÷ (Battery efficiency × DoD)Required Ah = Required Wh ÷ DC voltageRecommended Ah = Required Ah × (1 + Design margin)This is a planning-level model. Confirm final compliance with detailed layout, mounting heights, spacing rules, and verified photometrics.
Emergency lighting designs often start with a minimum horizontal illuminance along escape routes and open areas. This calculator uses area and target lux to estimate total lumens, helping you compare corridor zones, stair landings, and assembly spaces with consistent assumptions. Typical targets range from 0.5 to 2 lux depending on the space and code. Treat results as a planning baseline before detailed layout checks and uniformity verification.
Utilization factor reflects how efficiently luminaire light reaches the working plane after room geometry and surface reflectances. Maintenance factor represents lumen depreciation, dirt accumulation, and cleaning cycles. When UF or MF is reduced, required lumens rise quickly. For example, UF 0.60 and MF 0.80 yield an effective factor of 0.48, meaning lumens increase by about 2.08×. Using conservative factors can protect compliance during end-of-life conditions and harsh environments.
The lumen method estimates fixture quantity by dividing adjusted lumens by emergency-mode lumens per luminaire, then rounding up. Higher output luminaires reduce quantity but may change spacing and glare behavior. Use emergency-mode photometric values, not normal-mode ratings, and consider optical distribution for corridors versus open rooms. The calculator also provides a rough spacing proxy based on area per fitting, which supports early clustering decisions before photometric software is applied.
Battery sizing links the emergency load to the required runtime. Total wattage is scaled by driver efficiency, then converted to watt-hours for the autonomy period. Battery efficiency and allowable depth of discharge reduce usable energy, so the required capacity increases. The amp-hour estimate is derived from Wh divided by DC voltage, commonly 12, 24, or 48 V systems. A design margin adds reserve for temperature effects, ageing, and manufacturing tolerances.
Recharge time targets influence charger power. The calculator converts recommended amp-hours into energy, then estimates average charger watts needed to refill within the selected hours, accounting for charger efficiency. In practice, allow headroom for charging profiles, temperature compensation, and simultaneous standby loads. For documentation, export results to CSV or PDF, record assumptions, and align the final design with local standards, routine testing intervals, and maintenance plans.
It estimates total emergency-mode lumens needed from area and target lux, then adjusts for utilization and maintenance losses. It does not replace a detailed point-by-point layout using manufacturer photometric files and mounting-height checks.
Use project assumptions or past designs. UF depends on room index, reflectance, and optics; MF depends on cleaning cycle and lumen depreciation. Conservative values increase required lumens and reduce compliance risk at end of life.
Depth of discharge restricts usable energy to protect battery life. If DoD is lower, more total capacity is required to deliver the same watt-hours during autonomy, especially after efficiency losses and added design margin.
No. The spacing is a rough proxy based on average area per luminaire. Use it for early planning only, then confirm final positions with photometric calculations, route geometry, obstructions, and any local spacing-to-height rules.
The model converts recommended amp-hours into energy at the selected DC voltage, divides by recharge hours, and accounts for charger efficiency. Real chargers may need extra headroom for charge profiles, temperature compensation, and standby loads.
Yes for estimation. For self-contained units, use lumens and watts per fitting and treat each battery separately. For central systems, use total load and a shared DC voltage, then confirm distribution losses and protection devices.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.