IES RP-6 Sports Lighting Standards: Plain-English Guide
ANSI/IES RP-6 is the recommended practice that defines how to light sports facilities. It sets target footcandles, uniformity ratios, glare limits, and light-trespass guidance for each sport and class of play. In plain terms, it is the rulebook that makes sure a field is bright enough, even enough, and neighbor-friendly for its level of use — and when a credible specification says "design to IES RP-6," this is what it means.
This guide explains what RP-6 actually covers, how the class of play drives every number, why the standard insists on maintained values, and why designing to it protects your budget, your approvals, and your ability to compare bids fairly.
What RP-6 covers
RP-6 (published by the Illuminating Engineering Society) is not a single footcandle number — it is a structured set of recommendations. For each sport and level of play it specifies maintained illuminance (horizontal, and for higher levels vertical footcandles toward cameras and players), uniformity ratios (how even the light must be), glare limits (to protect athletes), and light-trespass guidance (to protect neighbors). Together these define what "good" means for a given facility, replacing guesswork with measurable, agreed targets.
Class of play: the decision that drives everything
| Class | Typical use | Demands |
|---|---|---|
| Class I | Professional / broadcast | Highest light, tightest uniformity, high vertical fc |
| Class II | Collegiate / competitive | High light and uniformity |
| Class III | High school / club | Competition-level targets |
| Class IV | Recreational | Lower light, looser uniformity |
RP-6 groups facilities into classes based on level of competition and spectator capacity, running roughly from Class I (professional and broadcast) down to Class IV (recreational). The class is the most consequential choice in the whole project, because it sets the footcandle target, the uniformity ratio, and whether vertical illuminance is required — which in turn drive fixture count, pole height, and cost. Picking a class higher than you need over-builds and over-spends; picking one too low leaves you with a field that underperforms for its actual use.
Why RP-6 protects you
Designing to RP-6 gives you documented, defensible performance. That matters in three concrete ways. It wins approvals, because zoning boards and athletic governing bodies recognize the standard. It satisfies funders — booster clubs, school boards, and municipalities — who want assurance their money buys a field that meets a real benchmark. And it lets you compare bids fairly: when every vendor designs to the same RP-6 class, you are comparing equivalent outcomes instead of mismatched promises, and a suspiciously cheap bid that quietly under-designs becomes visible.
Maintained values and the light loss factor
RP-6 targets are maintained values — the light level after normal depreciation, not opening night. Lenses gather dust and LEDs slowly lose output over their rated life, so a responsible design applies a light loss factor, effectively designing to a higher initial level so the field still meets its target years into service. A design quoted only in bright initial footcandles, with no light loss factor stated, is not really an RP-6 design. A photometric study using real IES files proves the maintained numbers before installation. Duvon designs every layout to RP-6.
Frequently asked questions
What is IES RP-6?
The Illuminating Engineering Society's recommended practice for sports and recreational lighting — it defines target footcandles, uniformity, glare limits, and spill guidance by sport and class of play.
What is class of play?
A grouping by level of competition and spectator capacity, roughly Class I (professional/broadcast) to Class IV (recreational). Higher classes need more light, tighter uniformity, and vertical illuminance.
What does "design to RP-6" mean?
Choosing the correct class and designing the layout to meet RP-6's maintained footcandle, uniformity, glare, and spill targets for that class, then proving it with a photometric study.
Why does RP-6 use maintained values?
Because light output declines over time. Maintained targets, achieved with a light loss factor, ensure the field still meets its goal years later — not just on opening night.
How do I know which class my facility is?
It follows your level of competition and expected spectators. A lighting designer confirms the class before specifying fixtures, since it drives every other target.
Get a free certified RP-6-compliant photometric layout for your facility's class of play. Request it at duvonlighting.com/free-quote.