Good lighting design requires good lighting controls design. As a result, best practices are essential for lighting controls, particularly as systems become more sophisticated to meet increasingly complex requirements.
It is undeniable that, with restrictive energy codes and the expanded capabilities afforded by the inherent controllability of LED lighting, lighting control systems are becoming increasingly complex. What does that mean for the designer? It means the control system can do a whole lot more than the traditional basics of manual switching and dimming. It also necessitates a certain level of diligence to ensure the right solution is selected based on the project requirements and that the installed system performs and is maintainable in accordance with the design intent.
Communicating this design intent to the right members of the project team involves two best-practice documents defined in ANSI/IES LP-16: Documenting Control Intent Narratives and Sequence of Operations—the Control Intent Narrative (CIN) and Sequence of Operations (SOO). Taking the time to incorporate these documents into one’s design practice can result in the selection, proper installation, and programming of appropriate control solutions, with the value increasing depending on the project’s complexity.
In this column, I will explain these documents and introduce a new, free tool created by the Lighting Controls Association (LCA) to support designers adopting and using them as best practices.
Written for the owner and design team, the CIN provides a non-technical, non-enforceable description of the project goals and what the lighting control system needs to do to satisfy the owner’s requirements. In ANSI/IES LP-16, the IES outlines four major elements of a CIN: a general description of the project goals, control strategies needed to satisfy these goals, a basic description of the lighting control system, and a basic SOO for each general space type or specific space.
The CIN serves as a “living document” (amended and fleshed out over time) and the controls roadmap for the entire project team—a common guide and reference. Once approved, it serves as the basis for the SOO.
If the CIN is general; the SOO is where the rubber meets the road—converting a general description into an explanation of the control system that is specific, measurable, and contractually enforceable.
So, what does “sequence of operations” mean? A sequence is a series of events that happen one after the other. In the case of a lighting control solution, this sequence begins with a trigger (input that initiates a command) followed by enacted functions (how the lights should behave, a combination of a lighting control strategy and programming). One example is when someone leaves a private office (the sensor does not detect occupancy, producing a trigger), and then the lights turn off after a specific period of time. More-advanced sequences may have multiple triggers and functions that interact.
In the SOO, the designer defines these triggers and sequences for each space and control point. This may include any settings necessary to achieve the desired use of the space and other occupant needs, which are used to program the system.
There is no gold standard for an SOO, but its foundation includes the spaces defined by the CIN, triggers, and functions. The following information is also essential for inclusion in the SOO or supplemental documentation.
Zones/groups and addresses: A zone/group is one or more lights grouped and assigned to a designated control strategy. The group may be luminaires wired together or grouped via the luminaire address in the case of luminaire-level lighting control.
Architecture/topology: refers to the physical organization of devices and luminaires (architecture) and the connections between them (topology). Examples of architecture include networked and standalone devices. Examples of topology include daisy chain and mesh.
Setpoints: parameters for how the controls should respond. A typical setpoint in a luminaire is brightness (intensity). Another example is the sensitivity or timeout of a sensor. The SOO should clearly define the setpoints, their intended function, and the triggers that activate them.
Scenes (presets, cues, programs): pre-programmed functions of luminaires that are activated by triggers. The most common scenes identify the luminaire intensities required to create specific visual conditions, including fade rate (the amount of time needed for scene transitions). The SOO should identify how many scenes will be programmed and how they will be triggered.
Writing the SOO involves taking the CIN and specifying and measuring its outcomes. Due to the amount of information that may need to be portrayed, it can be helpful to break it down into a format such as a matrix. ANSI/IES LP-16 provides a good example of this. Vertically, there is a list of specific spaces or space types matched to columns identifying control strategies and components such as integration.
In Figure 1, there is a portion of another example SOO developed by the LCA based on the 2024 version of the International Energy Conservation Code (IECC). In the complete SOO, a matrix of office spaces, control strategies, and minimum setpoints required by code is presented in a quick-reading visual shorthand.
As an example, in this snippet focusing on occupant sensors, we see that the 2024 IECC requires a sensor to reduce lighting to no more than 20% of maximum lighting power within 20 minutes of vacancy detection in stairwells. When the sensor detects the stairwell as being occupied, the lights will turn on to full power or raise to a predetermined occupied level.
Figure 1 is a snapshot from a new tool that the LCA is developing—a series of Excel spreadsheets offering CIN/SOO documents for many major building types covered by the IECC and populated with requirements from the 2024 version covering control strategies and scenes as well as systems integration. Written by a lighting designer, these spreadsheets are freely available at LightingControlsAssociation.org and function as both a CIN and SOO. They are being published for educational purposes but can be used by designers as a starting point, modified based on specific project parameters. By removing the heavy lifting of getting a SOO started, it is our hope that we can accelerate the adoption of these best practices.
Adopting the best practices of the CIN and SOO from ANSI/IES LP-16 can facilitate appropriate control selection, smoother installation, and system programming that meets the operational intent of the space and satisfies its occupants. Developing a repeatable template can be time consuming, which is why the LCA is producing a series of CIN/SOO templates for many popular building types based on the latest version of the most-commonly adopted energy code. Please review the new templates and let us know what you think.
Gary Meshberg, LC, CLCP, LEED-AP, Member IES, is chair of the Lighting Controls Association, a council of NEMA.
