In 2020, the Illuminating Engineering Society (IES) published ANSI/IES LP-6-20, Lighting Control Systems: Properties, Selection, and Specification. Drawing on the Lighting Controls Association’s Education Express offering as a primary source, this 111-page Lighting Practice and American National Standard provides an excellent foundation for designing with lighting control systems.
Lighting controls
Lighting controls are devices and systems that enable the right amount and color of light to be produced when and where it is needed, while potentially generating useful operating data. Combinations of inputs (manual, occupancy, time, light) and outputs (dimmed, stepped reduction, On/Off, BMS commands) constitute a menu of major lighting control strategies used to support visual needs and/or energy management.
Because of the latter, lighting controls are required by the majority of commercial building energy codes and promoted by utility rebate programs. Devices may operate standalone or connect within systems using wiring or wireless communication. Connection within a network facilitates single seat control, programmability, data extraction, and comprehensive integration with other building systems via single or limited points of access to the network.
Lighting Control Systems: Properties, Selection, and Specification is a comprehensive and excellent primer for the rapidly expanding world of lighting control. Basic concepts, control strategies, controlled light source behavior, wiring, protocols, control equipment, and applicable standards are included. One area bears special attention, which is incorporating controls into lighting design. Good design practices and a disciplined approach are important with lighting controls, particularly as control systems become more complex.
The IES publication goes into significant detail by inserting design considerations when describing technology. It also outlines major design considerations, which will be the focus of this article. In a nutshell, as IES states, “A successful lighting control system satisfies the design intent and owner’s operational needs.”
Design considerations
As with designing a lighting system, lighting control system design begins with understanding the user and the owner project requirements. What does the owner want the lighting controls to do, and what requirements and limitations exist regulating their implementation in the design?
At the user level, automatic controls should be reasonably unobtrusive in effect (often necessitating dimming) and able to be overridden where necessary, and all manual controls should be conveniently located and intuitive to operate. All controls should be maintainable by the facility staff, which may require training to be provisioned for this purpose.
At the application and organizational level, owner requirements should be defined, with a design document called the Owner Project Requirements (OPR) being recommended. This will include facility and/or space purpose, operating schedules, applicable codes and standards, integration, project goals, and preferred vendors. The OPR may start the project somewhat vague and become fleshed out over time.
Control zoning
Control zones deserve special attention as they define the relationship between the lighting and its control system by serving as a primary building block of the control system design. A control zone (aka, group, channel) is one or more light sources simultaneously controlled by a lighting control output. A simple example is a row of luminaires adjacent to windows, which may be zoned for daylight response while also being grouped in a larger zone for vacancy sensor-based shutoff.
Because of energy codes, the overall trend is toward smaller zoning, which generally makes the lighting control solution more flexible, responsive, and energy-saving while generally increasing the occupant experience and comfort of the space. While energy codes serve as a minimum goal for control zoning in new and major renovation projects, additional zoning may be required for other purposes such as visual needs. For example, in a classroom, the lights near the windows may be zoned within daylight zone(s) for daylight response and all lights zoned for automatic shutoff with manual On (override). For teaching purposes, however, lighting in the teaching area (and luminaires dedicated to the whiteboard) may be separately zoned from the student area with manual dimming. An emerging trend is luminaire level lighting control (LLLC). This typically provides the greatest savings, design flexibility, and occupant experience all while helping to satisfy energy codes and LEED and other rating systems.
In the design, control zones may be expressed either as a written schedule (tabular) or as a visual plan (graphical, which may include color coding). Either way, the intent—what lighting groups are assigned to what control strategies—should be clearly articulated, which may entail accommodating detailed and overlapping strategies. The groupings should make sense for the application, with luminaires grouped for commonality in strategy, location, and purpose.
Design deliverables
IES states, “The more types of information that designers can include with their deliverables, and the greater their attention to facility personnel and users, the more likely the installed control system will be valued, understood, accepted, and maintained, while providing long-term energy savings and environmental benefits.” Along with the control zone plan, a critical document—one that is required for the owner by many energy codes—is the controls narrative or control system’s Basis of Design (BOD), foundational to expressing the design intent.
The controls narrative ideally restates the owner requirements and then describes how the lighting control system will functionally satisfy these requirements. Integral to the narrative is the sequence of operations, which defines how the control system will behave in response to various conditions or inputs. It may be written in a consistent format or put together as a matrix, while potentially referring other design documents such as wiring and networking diagrams, control zoning plan, equipment specifications, and product data. The result is a roadmap for the lighting control solution for all project stakeholders.
Additional deliverables include equipment specifications, one-line diagrams, and lighting and relay panel schedules.
Commissioning
The Commissioning Process provides a quality assurance process to ensure installed systems satisfy owner requirements and the design intent. By producing an OPR and BOD, the designer has taken significant commissioning steps. Additional important steps include verifying specified equipment arrives at the jobsite in good order, functional testing of a sampling of control points, training of facility personnel so they can maintain the system, and turnover of documentation (Systems Manual) to the owner.
A good lighting design includes a good controls design
Effectively designing a lighting control system, even highly complex solutions, relies on familiar design best practices, though it may require a disciplined approach. By adopting these best practices and applying them to a knowledge base of control technology, designers position themselves for a broad range of project types. Lighting Control Systems: Properties, Selection, and Specification provides an excellent foundation for learning about the expanding world of lighting control, along with Lighting Controls Association Education Express courses.
Click here to order ANSI/IES LP-6-20.
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