Outdoor Lighting Standards Guide

Outdoor Lighting ANSI Standards: Which Standards Actually Matter?

There is no single “ANSI outdoor lighting standard.” ANSI accredits standards developers, while organizations such as the Illuminating Engineering Society publish individual ANSI-approved standards for different outdoor-lighting applications.

For a homeowner planning landscape lighting, ANSI/IES RP-47-23 is much more relevant than a roadway-lighting standard. For glare and uplight, TM-15-20 matters. For LED photometric test data, LM-79-24 matters. The right document depends on the question you are trying to answer.

This guide belongs to our Landscape Lighting Electrical Code & Safety Guide and separates lighting-design standards from electrical-code and product-safety requirements.

Quick Answer: The Outdoor Lighting Standards Map

For most residential landscape-lighting projects, start with ANSI/IES RP-47-23 for landscape design, then use other standards only when the project raises a more specific question.

ANSI/IES RP-47-23

Landscape Lighting

Best fit for residential landscape-lighting design, site analysis, equipment, techniques, human/nature interaction and maintenance.

ANSI/IES RP-43-25

Outdoor Pedestrian Applications

Useful where people walk, gather and navigate outdoor environments, including lighting zones, glare, controls and environmental considerations.

ANSI/IES TM-15-20

Outdoor Luminaire Classification

Defines the Luminaire Classification System and Backlight, Uplight and Glare (BUG) ratings.

ANSI/IES LM-79-24

LED Photometric Measurement

Explains reproducible measurement of luminous flux, power, efficacy, intensity distribution and color quantities for solid-state lighting products.

ANSI/IES RP-8-25

Roadway & Parking Facilities

Relevant to streets, intersections, parking lots, garages and other vehicle-focused lighting—not ordinary backyard path lighting.

ANSI/IES/ALA RP-11-26

Residential Environments

A broader residential-lighting recommended practice covering interior and exterior residential environments.

Most homeowners do not need to buy every standard. The useful first step is knowing which document governs the lighting question you are actually trying to solve.

This guide was reviewed by Philip Meyer, a lighting specialist with 25+ years of experience troubleshooting low-voltage systems.

Outdoor Lighting Standards: What Each Document Actually Does

↔ Swipe horizontally to see the complete standards comparison.

Standard Primary Topic Best Use Typical Residential Relevance Does It Replace Electrical Code?
ANSI/IES RP-47-23 Landscape lighting Landscape design process, techniques, equipment, maintenance Very High No
ANSI/IES RP-43-25 Outdoor pedestrian environments Walkways, plazas, pedestrian comfort, lighting zones, glare and controls High No
ANSI/IES TM-15-20 Outdoor luminaire classification BUG ratings and directional light distribution High No
ANSI/IES LM-79-24 SSL measurement LED lumen, efficacy, intensity and color test data Indirect but useful No
ANSI/IES RP-8-25 Roadway and parking lighting Roads, intersections, parking lots and garages Project specific No
ANSI/IES/ALA RP-11-26 Residential lighting Interior and exterior residential environments High No

ANSI/IES RP-47-23: The Most Direct Standard for Landscape Lighting

If you are designing lighting around a home, garden, tree, path, retaining wall, patio or landscape feature, RP-47-23 is the most directly relevant ANSI/IES recommended practice.

The IES describes RP-47-23 as a recommended practice for landscape lighting, a subcategory of exterior lighting. Its published contents include the landscape-lighting design process, site analysis, nature and human interactions, design considerations, lighting techniques, methods for landscape elements, equipment and maintenance.

What that means in practical terms

  • Start with the site and the purpose of the light, not fixture quantity.
  • Think about what people see from paths, windows and gathering spaces.
  • Consider plants, trees, wildlife and the nighttime environment.
  • Use beam control and placement instead of solving every problem with more lumens.
  • Plan for maintenance, aiming changes and landscape growth.

Our Portfolio Landscape Lighting pillar applies those ideas to practical residential outdoor-lighting decisions.

ANSI/IES RP-43-25: Outdoor Pedestrian Lighting

RP-43-25 is broader than landscape lighting. The IES describes it as providing pedestrian-oriented illumination recommendations for reassurance, safety, comfort, amenity and enjoyment in outdoor environments across lighting zones LZ-1 through LZ-4.

The 2025 edition includes lighting zones, color, controls, glare metrics, environmental considerations and responsible outdoor-lighting principles.

WalkwaysVisibility and pedestrian comfort
EntriesTransition and recognition
Plazas / PatiosHuman comfort and social use
Site BoundariesGlare and light-trespass control

This is especially relevant to larger residential properties, HOAs, multi-family sites, campuses and commercial landscapes where outdoor circulation is a central design issue.

ANSI/IES TM-15-20: BUG Ratings and Outdoor Luminaire Classification

TM-15-20 defines the Luminaire Classification System for outdoor luminaires. It organizes light distribution into meaningful angular zones and includes the familiar Backlight, Uplight and Glare (BUG) ratings.

B = Backlight

Light Going Behind the Fixture

Important near property lines, windows, neighboring yards and areas behind poles or wall-mounted luminaires.

U = Uplight

Light Going Into the Upper Hemisphere

Important for skyglow, dark-sky planning and fixtures that send unnecessary light upward.

G = Glare

High-Angle Light That Can Be Visually Uncomfortable

Important for drivers, pedestrians and neighbors who can see the bright source from normal viewing positions.

LCS

More Than a Single Number

The system uses luminaire photometric distribution to describe where the fixture actually sends its light.

BUG ratings are useful, but they are not a complete design by themselves. Mounting height, aiming, surrounding brightness, distance, spectrum and the viewer’s location still determine whether a real installation creates glare or trespass.

See our dark-sky-friendly fixture selection guide for practical fixture-selection context.

ANSI/IES LM-79-24: What Makes LED Photometric Data Comparable?

LM-79 is different from a design recommended practice. It is a measurement standard. The 2024 edition describes procedures for reproducible optical and electrical measurements of solid-state lighting products under standardized conditions.

It covers measurements such as total luminous flux, electrical power, system efficacy, luminous intensity distribution, chromaticity and spectrum.

Why a homeowner should care

If a manufacturer publishes serious photometric data for an integrated LED fixture, LM-79-style standardized testing is far more useful than a marketplace claim such as “super bright 3000 lumens.” Standardized test methods make product data more comparable.

LM-79 does not tell you whether 500 lumens is appropriate for your path. It tells laboratories how performance should be measured. Application standards and good design tell you how to use that output.

ANSI/IES RP-8-25: Roadway and Parking Lighting

RP-8-25 applies to roadway and parking facilities. Its scope reaches far beyond a normal front-yard path-light layout and includes roads, highways, intersections, crosswalks, parking lots, garages, tunnels, signs and related transportation environments.

It also addresses obtrusive light, controls, maintenance and environmental ratings. This becomes relevant when a “landscape” project actually includes a commercial parking lot, private roadway, large shared drive, development entrance or similar vehicle-focused environment.

Do not use residential path-light spacing rules to design a parking lot. Vehicle and pedestrian conflict zones require a different visibility and risk analysis.

ANSI/IES/ALA RP-11-26: Residential Lighting Is Broader Than Landscape Lighting

The current IES Lighting Library lists ANSI/IES/ALA RP-11-26 for lighting in interior and exterior residential environments. That makes it useful when the outdoor design needs to connect with porches, entries, garages, decks, patios and the visual transitions between the house and yard.

RP-47 remains the more specialized landscape-lighting document, while RP-11 provides broader residential context.

ANSI/IES Standards Increasingly Treat Outdoor Lighting as More Than “Enough Light”

Modern exterior-lighting guidance considers glare, light trespass, skyglow, color, controls and environmental effects—not simply whether a surface meets an illuminance target.

The IES position on outdoor light at night specifically points readers toward RP-43-25, TM-15-20, TM-37-22, RP-8-25 and RP-11-26 as relevant outdoor-lighting resources. It also emphasizes context, spectrum, output, orientation and environmental impacts.

For residential applications, that supports a simple principle: put the least amount of light necessary where it actually helps, and keep it out of places where it creates glare, trespass or skyglow.

Which Standard Should I Look At for This Outdoor Lighting Question?

↔ Swipe horizontally to see the complete question-to-standard map.

Your Question Best Starting Standard Why Also Check
How should I design landscape lighting around trees, beds and hardscape? ANSI/IES RP-47-23 Landscape-specific recommended practice RP-43 for pedestrian/site context
How do I reduce glare and uplight? ANSI/IES TM-15-20 Outdoor luminaire distribution and BUG ratings RP-43 and local outdoor-lighting ordinance
How are LED lumens and efficacy measured? ANSI/IES LM-79-24 Standardized SSL optical/electrical measurement Manufacturer photometric report
How should a pedestrian walkway or plaza be illuminated? ANSI/IES RP-43-25 Outdoor pedestrian applications and lighting zones RP-47 if landscape design is involved
How should a parking lot be illuminated? ANSI/IES RP-8-25 Roadway and parking facilities Local zoning and electrical code
Is my transformer/wiring installation electrically legal? Not primarily an ANSI/IES design question Electrical installation is governed by adopted electrical code and product requirements NEC, AHJ, product listing, instructions

ANSI/IES vs NEC vs UL/ETL: Three Different Questions

These systems overlap in an outdoor-lighting project, but they answer different questions.

ANSI/IES

How Should the Lighting Perform?

Design practices, photometry, glare, pedestrian conditions, landscape techniques, measurement and related lighting science.

NEC / AHJ

How Must the Electrical Installation Be Done?

Wiring methods, GFCI, burial, grounding, special locations and locally adopted electrical requirements.

UL / ETL / NRTL

Was the Product Evaluated for Safety?

Third-party product certification to applicable safety standards for the product category and intended use.

Local Ordinance

What Is Allowed at This Property?

Lighting zones, curfews, trespass limits, shielding, pole height and local dark-sky requirements can vary by community.

For product certification, see our UL vs ETL landscape lighting guide. For the electrical side, start with the Landscape Lighting Electrical Code & Safety Guide.

How to Read an Outdoor Fixture Spec Sheet Using These Standards

A good specification sheet should give you more than wattage and color temperature. Depending on the product, look for:

  • Initial lumen output
  • Input watts and efficacy
  • Beam or intensity distribution
  • Photometric file or report
  • CCT and color information
  • BUG rating where applicable
  • Environmental/wet-location information
  • Product certification/listing
  • Driver and control compatibility

These fields answer different questions. A BUG rating does not prove electrical safety, and a UL/ETL listing does not tell you whether the beam will create glare at your neighbor’s window.

How a Homeowner Can Use ANSI/IES Standards Without Becoming a Lighting Engineer

You do not need to calculate every photometric quantity to benefit from professional standards. Use them as a checklist for better questions.

  1. Identify the application. Landscape, pedestrian, parking, roadway or residential?
  2. Ask where the light goes. Not just how many lumens the fixture produces.
  3. Look for glare control. Shielding, aiming and source visibility matter.
  4. Check whether test claims are standardized. Especially for integrated LED products.
  5. Separate design from electrical safety. Good photometry does not excuse bad wiring.
  6. Check your local ordinance. Dark-sky or nuisance-light rules may be more restrictive.

Five Common Mistakes When People Talk About “ANSI Compliant Lighting”

1. Treating ANSI as a single outdoor-lighting rulebook

ANSI approval appears on many different standards. You need the document that matches the application.

2. Assuming an ANSI/IES design standard is an electrical code

It is not. Electrical installation requirements come from the adopted electrical code, local AHJ, product listings and installation instructions.

3. Using roadway criteria for a backyard

A parking lot, crosswalk and residential garden solve very different visual problems.

4. Believing a lumen number proves good lighting

Distribution, glare, mounting, aiming and background conditions determine whether those lumens are useful.

5. Treating BUG as a universal “good/bad” score

BUG components are tied to luminaire distribution and application context. A rating is information for design, not a substitute for design.

Official Standards Sources Used for This Guide

This guide is based on current IES and ANSI standards listings as of August 2026:

Outdoor Lighting ANSI Standards FAQ

What ANSI standard applies to landscape lighting?

ANSI/IES RP-47-23 is the IES recommended practice specifically devoted to landscape lighting.

What standard covers outdoor pedestrian lighting?

ANSI/IES RP-43-25 covers outdoor pedestrian applications and includes lighting zones, environmental considerations, glare, color and controls.

What standard defines BUG ratings?

ANSI/IES TM-15-20 defines the Luminaire Classification System and includes Backlight, Uplight and Glare ratings for outdoor luminaires.

What is LM-79?

ANSI/IES LM-79-24 is an approved measurement method for optical and electrical testing of solid-state lighting products. It addresses measurements such as luminous flux, power, efficacy, intensity distribution and color quantities.

Does ANSI/IES tell me how deep to bury landscape-lighting wire?

No. Burial and wiring requirements are electrical-installation issues governed by the adopted electrical code, product instructions and local requirements.

Does a BUG rating tell me whether a fixture is dark-sky compliant?

BUG data can be an important part of evaluating uplight, backlight and glare, but local dark-sky rules can include additional requirements such as shielding, lumen limits, color temperature, curfews and lighting zones.

Do homeowners have to follow ANSI/IES standards?

Whether a particular standard is mandatory depends on how it has been incorporated into a contract, specification, ordinance, code or other requirement. Many IES documents are recommended practices used by designers, engineers, agencies and communities to establish professional lighting criteria.

Bottom Line

The phrase “ANSI standards for outdoor lighting” describes a family of standards, not one universal rule. For residential landscape lighting, RP-47-23 is the most direct starting point. RP-43-25 helps with pedestrian environments, TM-15-20 helps evaluate backlight/uplight/glare, LM-79-24 helps interpret LED test data, and RP-8-25 belongs to roadway and parking applications. Use those lighting standards alongside—not instead of—the electrical code, product certification, local ordinances and manufacturer instructions.

Standards Verification

Standard editions change. The document numbers and editions on this page were checked against current IES/ANSI listings in August 2026. Always verify the latest edition and any locally adopted requirements before using a standard in a formal specification or permitted project.