New construction with exterior lighting
Parking lots, building perimeters, drive aisles, and pedestrian routes all trigger the requirement as soon as the permit needs proof of actual site performance.
Parking lot requirementsCOMPLETE GUIDE
What Is a Photometric Plan? Complete Guide (2026)
A photometric plan is a scaled technical document that maps how artificial light distributes across a site, showing fixture locations, a point-by-point grid of light levels measured in foot-candles, uniformity ratios, light trespass calculations at property boundaries, and a compliance summary referencing the applicable codes.
Scroll to continueTHE DELIVERABLE
What's inside a photometric plan.
A permit-ready photometric plan is a coordinated package. Review each layer in the same sequence a plan reviewer checks it: layout, calculations, contours, boundary values, and compliance notes.
Layer 7
Compliance summary
The final layer maps the package back to the governing code so a plan reviewer gets a pass/fail checklist instead of reconstructing the analysis from scratch.
When this summary is missing or vague, plans stall. The coordination failures behind that are the same ones we cover in why photometric plans get rejected at plan check.
WHEN YOU NEED ONE
Find your project type fast.
The requirement is triggered by the permit, not by the size of the job. These six scenarios cover the patterns that most often send owners, architects, and contractors searching for a photometric plan after hours.
Gas station and canopy work
Fueling sites are reviewed more aggressively because canopy shielding, pump islands, and the site perimeter interact in the same calculation package.
Gas station pageWarehouse and industrial yards
Warehouse projects blend employee parking, circulation zones, loading courts, and operational lighting into one permit set with tighter code coordination.
Warehouse pageSignificant fixture retrofits
Replacing legacy fixtures with LEDs changes optics, output, and color temperature enough that a fresh calculation is often required to show the real result.
Service overviewDark sky jurisdictions
Projects near protected land or in dark-sky zones need tighter BUG, CCT, and perimeter controls, with the plan documenting how the site stays contained.
Dark sky guideCalifornia Title 24 projects
California layers lighting power allowances, mandatory controls, and compliance forms on top of the photometric package, so the documentation burden is higher from day one.
Title 24 guideCODES & STANDARDS
See the numbers before you feel them.
A photometric plan does not exist in a vacuum - it is checked against a layered framework of IES recommended practices, model energy codes, and local municipal ordinances. Understanding which standards apply is the first step in producing a plan that passes review.
IES RP-8-25 is the current Illuminating Engineering Society reference for roadway and parking facility lighting, and it absorbed the earlier IES RP-20-14 parking guidance into one consolidated document.
ASHRAE 90.1-2022 and IECC set the lighting power ceiling, which is why zoned fixture selection matters so much on warehouse projects and other operational sites.
Municipal overlay codes are where real enforcement happens. Local tables for illuminance, uniformity, and property-line trespass are what the reviewer actually checks at plan review.
| Application | Min fc | Intensity | Uniformity | Reference |
|---|---|---|---|---|
| Parking lot (basic) | 0.2 fc | 20:1 max:min | IES RP-8-25 | |
| Parking lot (enhanced security) | 0.5 fc | 15:1 max:min | IES RP-8-25 | |
| Parking structure (general) | 5 fc | 4:1 avg:min | IES RP-8-25 | |
| Warehouse exterior | 5-10 fc | Varies | IES + OSHA | |
| Gas station canopy | 20-30 fc | 4:1 | Jurisdiction-specific |
HOW THEY'RE CREATED
The software is technical. The workflow should feel clean.
AGi32DIALux EVO
Every photometric plan starts with the same raw material: a site plan and a set of fixture photometric data files. The designer imports the geometry, places luminaires using the manufacturer's IES files, and iterates until the site meets illuminance, wattage, uniformity, and property-line constraints together.
The two industry-standard tools are AGi32 and DIALux EVO. AGi32 dominates U.S. exterior site lighting; DIALux EVO is widely used for broader lighting workflows and photorealistic visualization. The tradeoffs are covered in our DIALux EVO vs. AGi32 guide.
From the client side, the workflow still feels simple: project intake, scope confirmation, design and calculation, then delivery with revision support. Our process guide breaks that sequence down from first email to permit-ready package.
01
Project Intake
Collect the site plan, fixture intent, jurisdiction, and any special lighting zones or reviewer notes.
02
Scope & Fee
Review the geometry and code requirements, then confirm the fee and revision path before modeling begins.
03
Design & Calculation
Model the site, optimize spacing and optics, and verify light levels, trespass, and wattage together.
04
Delivery & Revisions
Issue the permit-ready package and absorb real review comments or scope changes without losing the thread.
COST & TIMELINE
Answer the two questions everyone asks first.
Typical plan fee
$300 - $2,500
Most commercial projects
Standard delivery
3 - 7 Days
Rush options available
Most commercial photometric plans cost between $300 and $2,500. Straightforward parking lots sit near the low end; multi-zone sites, dark-sky jurisdictions, and California Title 24 projects push upward. For a fuller breakdown, see the 2026 pricing guide.
Standard delivery is 3-7 business days, with 48-hour, 24-hour, and same-day rush options when the inputs are already organized. Most professional plans include one or two revision rounds in the base scope.
The plan itself is usually the fastest part of the permit timeline. Passing on first submittal saves more schedule than delivering a day earlier and bouncing back with avoidable comments.
The role of IES files in the calculation
Every number on a photometric plan depends on the accuracy of the fixture's photometric data. An IES file (.ies) is the standardized text file that describes a luminaire's measured light distribution based on laboratory testing.
When the software reads that file, it reconstructs the fixture's three-dimensional light pattern and predicts how much light lands on any surface at any angle. Without the actual IES file, the model falls back to approximations that can be off by 20-40%, which is enough to turn a passing plan into a rejection or a dark field condition.
If a manufacturer cannot produce an IES file, treat that as a red flag. The market offers hundreds of tested alternatives, and a permit-ready calculation should never depend on a fixture with undocumented photometric behavior.
Free plans vs. professional plans
Many LED manufacturers offer free photometric plans as a sales tool. You send a site plan, they model their fixtures, and you receive a layout at no charge. That can work when the jurisdiction is simple and you already know which product line you intend to buy.
The limitation is structural: the design is constrained to the manufacturer's catalog, the compliance narrative may be thin, and the model is not optimized across competing products or permit strategies. That matters more as the jurisdiction gets stricter.
A professional, manufacturer-agnostic plan starts from the code requirements and site conditions, then selects the best fixture solution regardless of brand. The tradeoff is cost; the benefit is manufacturer-agnostic flexibility and a fuller compliance package. We break that down in free vs. professional photometric plans.
Common reasons photometric plans get rejected
Plan review rejections follow predictable patterns. Most are coordination failures, not exotic engineering problems, which is why they are cheaper to prevent than to fix late.
Missing compliance summary
A calculation grid without the governing code reference forces the reviewer to interpret the design. If the plan does not say what standard it was checked against, approval slows immediately.
No property-line trespass verification
Many rejections are triggered at the edge, not the center. If the grid stops short of the boundary, there is no proof the site keeps light off neighboring property. That is exactly what light trespass calculations are for.
Initial lumens instead of maintained lumens
IES standards are written around maintained performance. If the Light Loss Factor is wrong or missing, the plan overstates performance and experienced reviewers notice quickly.
Fixture schedule and calculations do not match
A changed fixture family, a missing schedule entry, or an updated cut sheet without recalculating breaks trust in the whole package. Once the reviewer sees one mismatch, every other number becomes suspect.
Energy code wattage exceeded
The design can satisfy illuminance and still fail if total connected load exceeds the applicable allowance. Better efficacy and spacing solve that problem; ignoring it does not.
How to read a photometric plan
Start with the site background so you understand the geometry. Then match the fixture layout to the schedule, read the point-by-point grid, and check where the low values sit relative to entries, crossings, loading edges, and exit paths.
After that, move to the iso-footcandle contours and then the property-line values. If the site borders residential property or carries a published trespass limit, those edge numbers can matter more than anything in the middle of the lot.
Finish with the compliance note. When the geometry, fixtures, grid, contours, and code summary all tell the same story, you are looking at a permit-ready package. For a shorter field version, see how to read a photometric plan.
FAQ
Frequently asked questions
The basics people ask most often are usually the same: what the document is, what it costs, how long it takes, and whether the work can stay manufacturer-agnostic. The answers below keep those details scannable without removing them from the page source.
A photometric plan is a scaled technical document that maps how artificial light distributes across a site, showing fixture locations, a point-by-point grid of light levels measured in foot-candles, uniformity ratios, light trespass calculations at property boundaries, and a compliance summary referencing the applicable codes. It is required by most US municipalities for commercial building permits involving exterior lighting.
Most commercial photometric plans cost between $300 and $2,500, depending on the number of lighting zones, site complexity, jurisdictional code requirements, and turnaround time. Simple single-area projects fall near the low end; multi-zone sites or code-complex jurisdictions push toward the high end.
Standard turnaround is 3 to 7 business days for most projects. Simple single-zone sites can often be completed in 48 hours. Same-day and 24-hour rush delivery is available at a premium.
Cities require photometric plans for new construction with exterior lighting, parking lot development or redevelopment, gas station and canopy work, warehouse and industrial exterior lighting, significant fixture retrofits, and any project in a dark sky jurisdiction or California Title 24 zone. The requirement also applies to renovations where existing fixtures are replaced with different outputs or optics.
No. A manufacturer-agnostic photometric plan can be built around any fixture from any manufacturer, as long as the designer has the fixture's IES photometric data file. That flexibility is the key difference between a professional plan and a free plan tied to a specific manufacturer's product catalog.
A photometric plan is the calculated documentation — foot-candle grids, uniformity ratios, and compliance data required for permit approval. A full lighting design may also include aesthetic considerations, control strategies, energy modeling, and specification development. For permit purposes, the photometric plan is typically the only component the building department requires.
The two industry-standard tools are AGi32 (commercial software by Lighting Analysts, ~$133/month, dominant for US exterior site plans) and DIALux EVO (free software by DIAL GmbH, widely used for interior design and international projects). Both calculate illuminance from manufacturer IES photometric data files.
The software is accessible — DIALux EVO is free and AGi32 offers trials. But producing a permit-ready plan requires knowledge of IES illuminance standards, local code requirements, energy code limits, Light Loss Factors, and the specific documentation format your plan reviewer expects. Most project teams find it faster and cheaper to commission a professional plan than to learn the software and the code landscape.
If your project is already moving and you need a permit-ready package rather than more background reading, review the service overview or send your project details with whatever site plan you have now.
READY WHEN YOU ARE
Ready to get your photometric plan?
Send the site plan, fixture intent, and jurisdiction if you have them. We'll scope the work, confirm the fee, and start the same day.