• Mary Harris

Switches Be Trippin'

Updated: Nov 6, 2019


With all of the different codes, it can be confusing to tenants or building owners as to what applies to them. Energy codes are no different. There are two standards that are recognized in the US: ASHRAE and the International Energy Conservation Code (IECC). Virginia follows the IECC.

One of the main parts of the IECC we deal with in design is Interior Lighting Controls.


Lighting controls, for small projects, are broken down into 6 main parts in the IECC (If you really want to geek out on code it's Section C405).


1. Manual Lighting Controls

2. Light Reduction

3. Automatic Shutoff

4. Occupancy Sensors

5. Daylight Zone Control

6. Specific Application Controls


Manual Lighting Controls



Manual Lighting Controls [1] (IECC C405.2.1)



These are your standard light switches you find everywhere. Per the IECC, "all buildings shall include manual lighting controls in each area enclosed by walls, or floor-to-ceiling partitions." [1]

Exceptions to this are areas designated as security or emergency areas that need to be continuously lit and lighting in stairways or corridors that are elements of the means of egress.










Light Reduction


Light Reduction (C405.2.1.2)

We are all familiar with dimming lights for ambiance, but it's also a code requirement.

Each area that is required to have the manual controls above, are also required to be able to reduce those loads in a uniform pattern by at least 50%.


There are several ways to achieve this. In our small project world, there are two popular ways to accomplish this. The first is dual switching alternate rows of luminaries. This is great for warehouses, kitchens, and open spaces where dimming lights doesn't make sense.


The other method is the most obvious - controlling all lamps with dimming switches or panels. There are several types of dimming available so it's recommended you work with a lighting representative when selecting your lights to be sure the dimming types match.


Of course, there are exceptions to light reduction. Reduction controls aren't required in areas that only have one luminaire (with rated power less than 100 watts); areas controlled by occupancy sensors; corridors, equipment rooms, storerooms, bathrooms, lobbies, electrical or mechanical rooms; sleeping units (section C405.2.3); spaces that use less than 0.6 watts per square foot; daylight spaces that comply with C405.2.2.3.2.


Automatic Shutoff


Automatic Shutoff (C405.2.2.1)

The IECC is all about energy, so it makes sense that lights should be shut off when not in use.


Time clocks allow you to program a schedule based on normal business hours and are best used to automate in open offices, retail sales floors, hallways, common areas and other open areas that have predictable hours.


Occupancy sensors can also be used to achieve automatic shutoff and are best used to control localized, enclosed spaces, where occupancy may not be as predictable such as bathrooms, break rooms, conference rooms, and classrooms.


For the fine print on this one, the exceptions are emergency lighting does not need to be controlled, and spaces that are sleeping units, spaces were patient care is provided, spaces where the shutoff would endanger occupants, and spaces with lighting intended for continuous operation.


Occupancy Sensors

Occupancy Sensors (C405.2.2.2)

Occupancy sensors are the jewel of lighting controls. Wow! With one device, you can control light reduction, automatic shutoff and meet energy needs.


They are required to be installed in all classrooms, conference rooms, break rooms, private offices, bathrooms, storage rooms, and janitorial closets and all other spaces 300 sq ft or less. These devices have to be installed to turn off the lights within 30 minutes of all occupants leaving the space.


Exceptions are public corridors, stairways, restrooms, primary building entrances and lobbies, and areas where manual on operation would endanger the safety or security of the room or occupants.


Daylight Zone Control


Daylight Zone Control (C405.2.2.3)


Daylight zones allow buildings to save energy by using the daylight available to them. A daylight area is defined as "the floor area substantially illuminated by daylight".


These areas include skylight zones - areas that are illuminated by one or more skylights, primary side-lit zones - areas directly adjacent to one or more windows, and secondary side-lit zones, areas not directly adjacent to a window but still gets daylight from nearby windows.


Lighting in these zones are required to be controlled separately from other lighting. These lights can be zoned to one controller or grouped into smaller zones, or even controlled per light.


The devices controlling daylights (per IEC405.2.2.3.2), "shall be capable of automatically reducing the lighting power in response to the available daylight," by either continuous dimming using automatic daylight-sensing controls that are capable of reducing the lighting as required by code, or by using stepped dimming with multi-level switching and daylight-sensing controls that are capable of reducing lighting power automatically to levels required by IECC.


Specific Application Controls

Specific Application Controls (C405.2.3)

Aren't those displays gorgeous? This is an example of a specific application control.


The IECC is pretty straightforward here. Basically any display lights, supplemental task lighting, lighting used for plant growth or food warming, etc must be controlled by dedicated control, independent of the controls for other lighting in the space.





Design teams have a wide range of control solutions at their disposal to comply with these requirements. Working with your architect, engineer and lighting representative collaboratively will help you set the right ambiance, and meet code requirements at the same time.


Fultz and Singh architect Justin Whiteford has one key piece of advice when selecting light controls: "Dim it down."


For more information on any of the above contact one of our electrical project experts at 833.TWO.WEEK or email us.


Helpful links:


Lutron: IECC 2015 Commercial Energy Code Application Summary


Lutron: IECC 2015 Commercial Energy Code Application Guide






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