Everything about beam angle selection for office spaces: narrow vs medium vs wide, spacing-to-mounting-height ratios, how beam angle affects uniformity and UGR, and fixture recommendations for open-plan, cellular, and co-working offices.
Beam angle is the angle at which a luminaire's light output drops to 50% of its peak intensity. It determines the spread of light — narrow beams (15-30°) create concentrated pools, medium beams (40-60°) provide balanced coverage, wide beams (90-120°) flood large areas. In office lighting, beam angle directly controls uniformity, glare (UGR), and the number of fixtures needed to cover a space.
The spacing criterion (SC) links beam angle to fixture placement: SC = spacing ÷ mounting height. A fixture with SC 1.2 mounted at 2.7m should be spaced approximately 3.2m apart for uniform coverage. For offices targeting U₀ ≥ 0.6 (per EN 12464-1), the spacing-to-mounting-height ratio should not exceed 1.5 for direct lighting or 1.0 for direct/indirect pendants.
Getting beam angle wrong means either dark spots between fixtures (too narrow) or excessive overlap and glare (too wide). The right beam angle is the one that produces uniform illuminance across the task plane with minimum fixture count — this is always specific to your ceiling height and room geometry.
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 |
|---|---|---|---|---|---|
| Office Type | Ceiling Height | Beam Angle | Fixture Recommendation | ||
| Open-Plan (Standard) | 2.7-3.2m | 80-100° | 600×600 LED panel, UGR < 19, SC 1.3-1.5 | ||
| Open-Plan (High Ceiling) | 3.5-5m | 50-70° | Suspended linear or downlight, SC 1.0-1.3 | ||
| Cellular Office | 2.7-3.0m | 60-80° | Recessed downlight or panel, UGR < 19 | ||
| Meeting Room | 2.7-3.5m | 60-90° | Dimmable panel + wall wash, SC 1.2-1.4 | ||
| Corridor | 2.4-3.0m | 100-120° | Recessed downlight, wide distribution | ||
| Reception / Atrium | 4-8m | 25-50° | Adjustable downlight or pendant, narrow distribution |
Spacing = SC × (Ceiling Height − Task Plane Height). For a 2.7m ceiling with SC 1.4 and 0.75m desk: 1.4 × 1.95 = 2.73m spacing. Wider beam = larger SC = fewer fixtures but watch UGR. Always verify with the manufacturer's photometric data for your actual room dimensions.