What is a photometric plan?
A photometric plan is a calculated lighting layout: software models every proposed fixture's light distribution across a site or space and proves the design meets the required light levels — and stays under the limits — before anything is installed. Jurisdictions require photometrics for site lighting, parking lots, and commercial exteriors to enforce their lighting codes: enough light for safety, no spill onto neighbors, no glare into the street. It is the lighting equivalent of a structural calculation: the proof, in numbers, that the design works.
Best price · Quotes back fast · PE stamps backed by Apex Grid Engineering
What the plan shows
A photometric plan overlays a grid of calculated foot-candle values on the site plan, with summary statistics: average, minimum, and maximum levels and the uniformity ratios between them. It shows point-by-point values at the property line — where light-spill limits apply — and at the street, where glare and spill restrictions protect drivers. The fixture schedule ties every symbol to a specific fixture, mounting height, and optic, and the calculations use the manufacturer's actual photometric files for those fixtures, not generic placeholders. Reviewers check the numbers against the local lighting code's table for the use: parking, walkways, sports, building entrances each carry their own required levels.
The rules it has to satisfy
Three families of requirements collide in a photometric design. Minimums for safety and the owner's operations — a parking lot too dark is a liability. Maximums and spill limits at property lines and residential adjacencies, which cap how much light can leave the site. And energy codes, which cap total lighting power and mandate controls, so the design cannot solve a uniformity problem by simply adding wattage. Dark-sky provisions in many jurisdictions add fixture shielding and uplight limits. Designing inside all three at once — enough, but not too much, at a legal power budget — is the actual engineering task.
When photometrics are required
Most jurisdictions require a photometric plan with the permit set for new commercial site lighting and major exterior alterations: parking lots, dealerships, fuel stations, sports facilities, warehouse yards, and commercial building exteriors. They are also standard in entitlement and site-plan review, where lighting is a neighbor-relations issue decided in public. Interior photometrics appear where light levels are contractual or code-critical — warehouses with rack layouts, industrial tasks, healthcare and laboratory spaces. If your project has exterior lighting and a commercial address, assume photometrics are in the submittal until the jurisdiction says otherwise.
What Torch delivers
Torch produces photometric plans as part of the electrical design, modeled from the specified fixtures' real photometric data, so the plan the reviewer approves is the plan the contractor can build with the specified equipment. The calculation grid covers the site and the property lines, the schedule states mounting heights and optics, and the design is checked against the jurisdiction's levels, spill limits, and the energy code's power budget in the same pass. If a fixture is substituted later, we rerun the affected area rather than letting the approved plan and the installed fixtures quietly part company.
The bottom line
A photometric plan is calculated proof that a lighting design hits required levels, respects spill and glare limits, and stays inside the energy budget — required for most commercial site lighting permits.
Torch Engineering PLLC · (480) 490-0064 · info@torchengineering.com — PE stamping backed by Apex Grid Engineering.