Outdoor Lighting
Lighting up an exterior isn't just about ambiance— it's also about code compliance. Here is what the code says about safety and efficiency when it comes to outdoor lighting.
Lighting up your home’s exterior isn’t just about ambiance—it’s also about code compliance. The International Residential Code (IRC) addresses outdoor lighting in several ways, and all the provisions are meant to provide a safer home for residents and visitors. Sometimes illumination is required for safety or security, but whether required or not, it must always be installed safely and provide a minimum efficiency.
The requirements for outdoor lighting aren’t very complicated, but they come from three model-code documents: the IRC, the National Electric Code (NEC), and the International Energy Conservation Code (IECC). Those requirements can all be found in the IRC, but they’re spread out among different chapters. This column cites the relevant outdoor-lighting provisions from the NEC where they are found in the electrical sections of the IRC, and from the IECC where they are found in chapter 11, which covers energy efficiency.
Exterior Doors
Section R318.1 of the IRC requires one exterior door for every house. If there are parts of the living space that can’t access this door, those parts of the house need their own door. This “required egress door” must provide access to grade and a path to a public way. Section E3903.3 (from the NEC) requires a lighting outlet and illumination on the exterior side of the door for increased safety and to allow visitors to be seen by those inside before they open the door.
Lighting for the required egress door must be controlled from a listed, wall-mounted lighting control device—in other words, a switch. But an exception in section E3903.3.1 for stairway lighting also applies to exterior doors, and it allows remote, central, or automatic control of lighting in lieu of a wall switch.
There is no limit to the number of additional exterior doors a house may have, and those doors can have access to grade or not. But when an additional door does have access to grade, section E3903.3 requires that at least one lighting outlet be provided on the exterior side of the door. Once again, the intent is security.
A foundational principle of the IRC is that it represents “minimum code,” which means requirements should only address what’s necessary for a safe dwelling, and additional requirements for convenience or good design are considered an overreach. So, though a light isn’t required outside a door to a private balcony without stairs to grade, it might be a welcome design choice.
The requirement for a light on the outside of an exterior entry door also applies to attached garages and detached garages with electric power. Similarly, if electrical power were added to an existing detached garage, a light outside all its exterior doors would then be required. The requirement does not apply to vehicle doors on a garage. A detached garage built without electrical service is not required to have exterior-door lighting.
Stairways
Section R325.7 of the IRC provides requirements for exterior stairway illumination. This section was modified in the 2015 edition when a previous requirement for all exterior stairways to be entirely illuminated was removed. Starting in 2015, only the top landing of an exterior stairway requires illumination.
The idea is to prevent falls down the stairs by illuminating the landing at the top of the stairs. It was decided that illuminating the entire stairway is an overreach of code, but showing occupants and visitors where stairs are located so they don’t fall down them is an appropriate requirement.
More specifically, section R325.7 requires an “artificial light source.” The lighting needs to be near the stairs, but it could be a nearby porch light switched from inside. It could be low-voltage lighting in the stair risers or on guard posts. It could even be a solar light with light-sensing automatic controls. Anything that will brighten up the top of the stairway at night, either automatically or with a manual switch, fits the goal of the provision.
In the specific case of exterior stairways that provide access to a below-grade basement door, a light must be provided at the bottom of the stairway, although the light required outside the basement exterior door could satisfy both. However, when a bulkhead door covers the stairway, a new exception in the NEC and in IRC section E3903.3 allows the light to be just inside the basement door but no further than 5 ft. from the bottom step of the exterior stairway.
Lighting Efficacy
Much like the electrical code chapters in the IRC originate from the NEC, the energy-efficiency requirements in the IRC come from the International Energy Conservation Code (IECC). The IECC provisions are renumbered in chapter 11 of the IRC. When describing lighting efficiency, both the IRC and IECC use the term “efficacy,” which describes a light’s illumination per watt of electricity consumed.
Section N1104.1 describes how lighting fixtures, or “luminaires,” must produce at least 45 lumens per watt of electricity used or must contain lamps (bulbs) with an efficacy of not less than 65 lumens per watt. As an example, a tungsten incandescent bulb has an efficacy of about 15 lumens per watt, considerably less than what is required by this code section.
LEDs (100 to 200 lumens per watt) and CFLs (50 to 70 lumens per watt) produce the required illumination. Section N1104.1 includes an exception for luminaires with a rated electric input of 3W or less, allowing many low-voltage path and accent lights that would otherwise fail the requirement.
Section N1104.3.1 describes exterior lighting controls. When exterior lighting for a house consumes 30W or less of power, there are no requirements for automatic operation. However, when more than 30W of power are consumed, three requirements must be met:
- The lighting must have a manual on/off switch that also provides automatic shutoff, like a timer.
- The lighting must automatically shut off when daylight is present.
- Manual controls that override the automatic shutoff must reset to automatic operation after 24 hours.
In summary, you can have all the outdoor lights you want if they meet the efficacy standard and turn off automatically so that you don’t leave them on during the day.
Low-Voltage Lighting
Few building departments issue building permits for low-voltage outdoor lighting, and the NEC provisions for low-voltage lighting are not found in the IRC. NEC article 411 provides about a page worth of requirements for systems operating at no greater than 30V AC or 60V DC. Typical low-voltage systems found at private residences are 12V DC.
Most provisions require that components in outdoor lighting systems be tested by national standards for safety. One critical section, 411.5(B), requires low-voltage lighting to be no less than 10 ft. horizontally from the edge of the water at pools and hot tubs. Article 680, which is specific for pools and hot tubs, provides additional details for low-voltage and line-voltage electrical devices and installation near pools and spas.
I have focused here on what the code requires for safety and efficiency, but there’s more to outdoor lighting than meeting the minimum. In the next issue, lighting designer David Warfel will explore thoughtful design and product choices for a landscape lighting plan.
Code CheckThis column cites the model 2024 International Residential Code and provides section number references to that edition. State and local governments often make amendments to the model IRC at adoption, so always verify the adopted and amended code edition as administered by your building authority. |
— Glenn Mathewson is a consultant and educator with BuildingCodeCollege.com.
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