A photometric plan is a lighting layout backed by calculated light levels. It shows how bright a site or room will be, how evenly light is distributed, and whether the design meets project requirements.
This overview is for architects, engineers, contractors, and owners who need to understand what a photometric plan includes and how to use it for design decisions and permitting.
What a Photometric Plan Shows and Why It Matters
Most lighting questions come down to the same issue: “Will this lighting work in the real space?” A photometric plan answers that with numbers and visuals. It helps you avoid dark zones, glare problems, and missed lighting targets before anything is installed.
Faster approvals and fewer field changes
A clear photometric plan supports permit reviews and coordination. It gives the team a shared reference for light levels, spacing, and performance. It also reduces last-minute fixture swaps that create delays and added cost.
- Shows expected foot-candles or lux across a defined calculation grid.
- Highlights hot spots, dark areas, and uniformity problems early.
- Documents fixture types, aiming, mounting heights, and quantities for installers.
What’s Included in a Photometric Plan
A photometric plan is typically produced from the fixture photometric data (often an IES file) and a model of the space. The output combines the drawing view with calculated results so the design can be reviewed and verified.
- Fixture locations, tags, and fixture schedule references.
- Calculated values on a grid (avg, min, max) in foot-candles or lux.
- Isolines or heatmap-style contours that show distribution and coverage.
- Uniformity ratios (for example avg/min and max/min) for performance checks.
Key metrics to check before you approve the design
When reviewing a photometric plan, focus on the values that impact safety, visibility, and comfort. The goal is not just “enough light,” but the right light, placed correctly, with acceptable uniformity and control of glare.
- Average: the overall target level for the space or area.
- Minimum: shows how dark the weakest areas get.
- Uniformity: confirms the lighting is even enough for the use case.
When You Need a Photometric Plan
Photometric plans are used anywhere lighting performance needs to be proven, coordinated, or optimized. This includes permitting, value engineering, and projects where uniformity and glare control matter.
- Permitting / documentation: many AHJs and owners want proof of light levels and coverage.
- Design coordination: confirms fixture spacing, mounting heights, and aiming work with the architecture.
- Performance troubleshooting: compares “expected” vs “installed” lighting when problems show up on site.
Get a Professional Photometric Plan
Key Takeaways
A photometric plan is a performance document. It helps you confirm light levels, uniformity, and coverage before installation. It also improves coordination between design, engineering, and construction teams.
If you need a photometric plan for permitting or to validate a lighting design, Stetra Lighting can produce a clear, contractor-ready package based on your layout, mounting heights, and selected fixtures.