When to use high bay vs low bay LED fixtures: mounting height thresholds, beam angle selection, lumen output requirements, and application-specific recommendations for warehouses, factories, gymnasiums, and retail spaces.
The distinction between high bay and low bay lighting is driven by mounting height, which dictates beam angle, lumen output, and optical design. High Bay = mounting height above 6-7m (20-25 ft). Uses narrower beam angles (60-90°) to project light downward against the inverse square law. Typical output: 15,000-50,000+ lumens per fixture. Applications: warehouses, factories, gymnasiums, aircraft hangars.
Low Bay = mounting height 3-6m (10-20 ft). Uses wider beam angles (90-120°) for broader coverage at lower heights. Typical output: 5,000-20,000 lumens. Applications: assembly areas, retail spaces, parking garages, workshops.
Inverse square law: doubling mounting height quarters the lux at floor level. A 20,000 lm high bay with 90° beam at 8m gives ~200 lx at floor. The same fixture at 12m gives only ~90 lx. This is why high bays need both more lumens AND tighter beams at greater heights.
Getting lux right is not optional — it's a regulatory requirement under EN 12464-1 (Lighting of Indoor Workplaces), which mandates minimum maintained illuminance levels for every office zone. Undershooting causes eye strain, headaches, and productivity loss. Overshooting wastes energy and causes glare. This guide gives you the exact numbers.
The table below lists maintained illuminance (Ēm) requirements for every common office zone per EN 12464-1. Use these values as the minimum design target — going slightly higher (10–20%) is acceptable to account for future degradation.
| Office Zone | Ēm (Maintained Lux) | Uniformity U₀ | UGR Limit | Ra (CRI) Min | Notes |
|---|---|---|---|---|---|
| 💻 Workstation (Desk) | 500 lx | ≥ 0.6 | < 19 | ≥ 80 | Measured on the task area (desk surface). Writing, typing, reading, data processing. |
| 🤝 Meeting / Conference Room | 500 lx | ≥ 0.6 | < 19 | ≥ 80 | Ensure dimmable for presentations. Consider tunable white for video calls. |
| 🎨 Design Studio / CAD Office | 750 lx | ≥ 0.7 | < 16 | ≥ 90 | Higher visual acuity for detailed technical drawings. Stricter UGR. |
| ☕ Break Room / Pantry | 200–300 lx | ≥ 0.4 | < 22 | ≥ 80 | Relaxation zone — lower illuminance acceptable. Warmer CCT (3000K) preferred. |
| 🚶 Corridor / Circulation | 150–200 lx | ≥ 0.4 | < 25 | ≥ 80 | Floor-level measurement. Emergency egress paths require minimum 0.5 lx backup. |
| 🗄️ Filing / Archive Room | 200–300 lx | ≥ 0.4 | < 22 | ≥ 80 | Vertical illuminance on shelves should be ≥ 150 lx at 0.2 m from floor. |
| 🚻 Reception / Lobby | 300–500 lx | ≥ 0.5 | < 22 | ≥ 80 | Higher end (500 lx) for reception desks where reading and visitor interaction occurs. |
| 🖨️ Print / Copy Area | 300–500 lx | ≥ 0.4 | < 19 | ≥ 80 | 300 lx general + 500 lx at service areas for maintenance tasks. |
| 🔧 Server / Technical Room | 200 lx | ≥ 0.4 | < 25 | ≥ 80 | Primarily for maintenance access. Emergency lighting required. |
Lux is a Goldilocks parameter — too little and people suffer; too much and you waste money while creating glare. Here's what happens at each level for a standard office workstation:
Key takeaway: The 450–550 lx range is the sweet spot for standard offices. Below 300 lx is a health and compliance risk. Above 750 lx wastes energy without meaningful visual improvement — the human eye's perceived brightness follows a logarithmic curve, so doubling lux from 500 to 1,000 only feels ~40% brighter.
Standard workstation illuminance. Uniform distribution across all desks critical.
Task + ambient layered. Desk lamp for focused 750 lx on documents, ambient at 300–500 lx.
High visual acuity for detailed drawings. CRI 90+ mandatory. Stricter UGR < 16.
500 lx general + 1,000 lx on examination areas. Tunable white for circadian support.
Use this table to quickly match your office type to the correct lux level and fixture specification. All values comply with EN 12464-1:2021.
| Office Type | Recommended Lux (Ēm) | CCT | CRI (Ra) | UGR | Suggested Fixture |
|---|---|---|---|---|---|
| Application | Ceiling Height | Recommended Type | Typical Fixture Spec | ||
| Small Workshop | 3-5m | Low Bay | 10,000 lm, 120°, IP54 | ||
| Assembly Area | 4-7m | Low Bay or High Bay | 15,000 lm, 90-100°, IP65 | ||
| Distribution Warehouse | 8-12m | High Bay | 25,000-35,000 lm, 60-90°, IP65 | ||
| Factory Floor | 6-10m | High Bay | 20,000-30,000 lm, 90°, IP65 | ||
| Gymnasium | 8-12m | High Bay (with glare control) | 30,000 lm, 60°, UGR < 22 | ||
| Retail / Showroom | 4-6m | Low Bay / Track | 10,000-15,000 lm, 90-120°, CRI 90+ |
Ceiling < 6m → Low Bay (wide beam, lower lumens). Ceiling 6-7m → Gray zone (run DIALux). Ceiling > 7m → High Bay (narrow beam, higher lumens). Ceiling > 15m → Specialized optics. Always verify with photometric software at actual mounting height — the inverse square law is unforgiving.