How to Take Control: Design guidance for lighting controls

Published On
Apr 15, 2022

Lighting control devices and systems enable the right amount and color of light to be produced where and when it is needed, while potentially producing useful operating data. Combinations of inputs (manual, time, occupancy light) and outputs (dimming, switching, color tuning, signals and data for other systems) offer a menu of strategies that support visual needs and energy management.

Within the larger LED revolution, a quieter one occurred in this category. Relatively rare 15–20 years ago, lighting controls have since become normal in new nonresidential construction due to building energy codes. Supported by utility rebates, they are also common in retrofits. According to the Department of Energy, by 2018, at least half of all commercial building floorspace was controlled by occupancy sensing or some other form of management.

During this time, control zones have steadily reduced in size to as small as single luminaires, with overlapping zones being common. Networking and wireless communication competed against traditional control hardwiring. Once the province of spaces such as conference rooms, dimming is widely available due to the inherent controllability of LED sources. Color tuning, notably tunable white, quickly developed as another readily accessible dimension of control.

The culmination of the lighting controls revolution is networking through dedicated low-voltage control wiring or wireless communication. This facilitates global single-seat control and building integration and could be foundational to an internet of things (IoT) scheme. Today, its ultimate expression entails automation, high flexibility, substantial energy savings and the potential to go far beyond energy to support user satisfaction and comfort as well as business operations through building operating data.

For electrical contractors who want to stay ahead of the curve, this means education and training. Those that design systems would likely benefit from learning about best practices as much as manufacturer training on setup and installation. Because lighting control systems are becoming more complex, good design practices and disciplined approaches are worth understanding.

In 2020 and 2021, the Illuminating Engineering Society (IES) published two lighting practices that can prove helpful. ANSI/IES LP-6-20, “Lighting Control Systems: Properties, Selection, and Specification,” offers a foundation in lighting controls. ANSI/IES LP-12-21, “IoT Connected Lighting” goes farther by focusing on networked lighting and IoT applications.

This article summarizes some of the design processes and key related considerations involved when designing with and specifying lighting controls, and then focuses on what’s needed for the most advanced systems.

Owner project requirements

A longstanding best practice for lighting design, building commissioning and effective lighting controls design is to understand the owner’s requirements. What does the owner want the lighting controls to do? What requirements and limitations affect the choice of the right solution?

A big part of this is user experience, because manual controls should be intuitive to use and conveniently located. Automatic controls, meanwhile, should be as minimally obtrusive as possible, which may necessitate dimming and the option to override when needed. The facility staff should be able to maintain all controls, which may require training.

All of these requirements should be described in the owner project requirements (OPR) design document, covering everything from space purpose, schedules, codes and standards, integration needs, preferred manufacturers and more. Note: the OPR may start off vague, it but should solidify over the course of the project.

Basis of design

Another best practice is to produce a basis of design (BOD), or a document that describes the intent or how the proposed design will satisfy the OPR. For lighting controls, this is typically called the written controls narrative and is required by the latest energy codes and standards.

In a nutshell, this narrative restates applicable owner requirements and then articulates how the proposed lighting control solution will functionally satisfy these requirements. The result is a common road map for the system that informs all participants on the project team and fuels the finished design.

A major feature of the narrative is the sequence of operations, which defines what the lighting control system will do in response to various inputs or conditions. The resulting document may be produced in a consistent text format or as a matrix, while referencing other design documents, such as wiring diagrams, as needed.

Control zoning plan

This important design document rides alongside the written narrative by showing the relationship between the control points and what lighting they control. A control zone (also called a group or channel) is one or more light sources simultaneously controlled by an output. In a classroom, for example, all luminaires may be zoned for automatic shutoff by a vacancy sensor, but the luminaires by the windows may be zoned for daylight response and the luminaires in the teaching and student areas may be separately zoned with dimmer switches.

The overall trend is toward smaller zoning as energy codes evolve toward flexibility and expected higher energy savings. Even so, they are a minimum, with additional zoning available for visual needs or even higher savings. The latest edition of the International Energy Conservation Code includes a compliance path based on luminaire-level lighting controls, which provides control zoning based on single luminaires. Otherwise, luminaires should be grouped for commonality in strategy, location and purpose.

The control zoning plan is typically articulated either in a tabular (written schedule) or graphical (visual/color-coded floor or lighting plan) format. Either way, the planned zoning should be clear, particularly when zones overlap.

Other design deliverables

Additional deliverables include equipment specifications, one-line diagrams and lighting and relay panel schedules. IES states in LP-6, “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.”

Commissioning

ASHRAE’s Principles of Building Commissioning (Guideline 0 and Standard 202) provides a quality-assurance process and step-by-step requirements for new buildings, though it can be applied in whole or in part to other types of projects, such as single systems.

Regarding lighting controls, besides delivering an OPR and BOD, other key elements include verifying specified equipment arrives at the job site in good order, functional testing of a sampling of control points and training facility personnel so they can maintain the system and documentation (systems manual) turnover to the owner. Of these, a written control narrative, functional testing and delivery of certain other documentation is required by a majority of commercial building energy codes.

Networked lighting and IoT

The above good design practices aid in furnishing an effective and properly functioning lighting control system. More advanced options, such as networked and integrated systems, may require a more disciplined approach and an understanding of subtle but important differences.

First off, IoT can be difficult to define because its features and benefits are evolving. In its simplest form, an IoT scheme networks sensors and computing devices that can be globally programmed, interoperate and generate and share data. This allows an operator to fine-tune system operation as needed to make it more responsive and energy saving, while generating building information that can be used for a range of services, such as space use and asset-tracking.

Lighting is considered potential infrastructure for an IoT solution, as luminaires are ubiquitous, connected to power and typically located at the ceiling plane. By inserting sensors/control points into these luminaires and networking them, we gain the ability to program and operate the system from a single access point and extract occupancy and other data that the software can use.

Major elements include the physical objects, data, network infrastructure and software. Communication may occur using a dedicated network, building network or the internet, with associated issues including managing data, response latency, cybersecurity and interoperability/integration. Data services may be built into the selected system or created using third-party apps.

When designing a centralized building-based networked control system, the first thing to note is that these projects are often more intensive than typical room-based control systems, requiring different expectations in terms of discipline and cost. The system’s designer should get involved as early as possible in the design process and be prepared to produce required design deliverables for the project stakeholders, which includes familiar players and maybe a commissioning agent, smart building program manager, building IT team and systems integrator. The relative role and influence of each of these players may differ based on the type of project and its goals, such as how many and which building systems will be required to interoperate.

Otherwise, during the programming phase, when the OPR is first formulated, the designer should be prepared to ask if data is being collected, what data is needed, whether any third parties will be contracted for tasks such as data analysis, system capabilities, level of expertise needed to operate and maintain the system and potential need for future-proofing. During the design phase, the designer may need to emphasize coordination to ensure the lighting control system properly integrates with other systems if needed, while providing network and cybersecurity requirements and information to the building IT team. A 6- to 12-month post-occupancy evaluation may be beneficial to confirm and tune outcomes.

Get control

The world of lighting controls has certainly come a long way in the last 10–20 years. While many devices remain relatively simple, generally the requirements, capabilities and systems have become more complex.

As always, education can be useful for electrical contractors to stay on or ahead of the curve to capture opportunities while minimizing risk.

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