Lighting control design insights
- By referencing a standard practice, design and documentation can be simplified to reduce confusion and errors during construction, commissioning and use of lighting control systems.
- ANSI/IES LP-16-22 provides a standard for documenting lighting control design intent.
- The control intent narrative and the sequence of operations are two documents outlined in ANSI/IES LP-16-22 that define lighting controls system.
ANSI/IES LP-16-22, Lighting Practice: Documenting Control Intent Narratives (CIN) and Sequences of Operations (SOO), as its primary objective, provides a standard for documenting lighting control design intent. Once that intent is developed by the designer, in coordination with the owner, user and/or architect, it needs to be translated into contractually enforceable and buildable construction documents that are clear and easy to understand by the contractor, manufacturer and installer.
The inaugural 2022 edition of LP-16, developed in collaboration between the American National Standards Institute (ANSI) and the Illuminating Engineering Society (IES), is not intended to be a standalone document or a design manual. In coordination with ANSI/IES LP-6, Lighting Practice: Lighting Control Systems – Properties, Selection and Specification and ANSI/IES LP-8, Lighting Practice: The Commissioning Process Applied to Lighting and Control Systems, LP-16 is intended to be a reference of best practices for developing and documenting the functionality of the lighting controls systems.
As a result, owners and occupants will be provided with a lighting system that functions as intended with less confusion and errors during the construction process.
Defining the CIN and SOO
ANSI/IES LP-16 outlines two documents that define the lighting controls system.
The CIN is meant to outline the requirements of the project and should be written in a format that is easily understood by all parties. The CIN should start with how the project owners and/or users intend the lighting controls system to operate including how the users will interact with the system and how the system should respond to inputs. If the overall lighting controls system is made up of multiple connected systems, the CIN should define how these systems will interact with each other.
The CIN should be written in complete sentences and in plain language and should complement the owner’s project requirements (OPR), conveying how the needs of the owners and/or users will be met by the lighting controls system. For example, electrical room lighting narrative might include:
“Electrical rooms should have two manual switches and should not rely solely on automatic shut-off. Normal lighting should be controlled by manual switch and occupancy sensor. Emergency lighting should be controlled by a separate manual switch and shall turn on to 100% upon loss of normal power.”
The SOO is meant to be a part of the construction documents and is intended to outline in precise terms and instructions how the lighting controls system shall perform and respond to inputs from individual occupants and connected systems and sensors. The SOO is an enforceable contract document and shall be written in unambiguous instructions to the contractor, integrator and/or commissioning agent.
An example that might be found in the SOO as it relates to electrical room lighting is as follows:
“A manual switch shall be provided to control all normal lights in the space. Ceiling occupancy sensors shall be provided such that all spaces within the room are within the minor motion range of the sensor, on all sides of free-standing equipment and shall be connected to the manual switch. Normal lighting shall turn off after 30 minutes of vacancy. Emergency lighting shall be controlled through a separate manual switch and shall be provided with a UL 924 relay. Emergency lighting shall turn on to 100% upon loss of normal power.”
It is important that the design of the lighting control system be considered at all phases of a project. Often, design of lighting controls is deferred to the later phases of the design process. This could lead to missed opportunities for integration or deviations from client or owner preferences outlined in earlier stages of design.
ANSI/IES LP-16 outlines ideal steps to consider at each major design milestone, including review and approval by applicable parties. Both the CIN and the SOO should be developed at different levels depending on the design phase as outlined below.
The CIN should start its development during the schematic design (SD) phase. Developed in conjunction with the OPR, the CIN should translate the overall needs of the owners and/or users into a space-by-space description of the lighting controls system. If the owner and/or user needs remote control or integration with heating, ventilation and air-conditioning (HVAC) or audiovisual (AV) systems, those requirements should be included in the CIN during this phase.
Local codes, standards and certification standards that will affect the design of the lighting control system should also be noted in the CIN at this time. Particular attention should be given to the locally adopted energy code. Although the two primary standards adopted as local energy codes, namely ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings and the International Energy Conservation Code, are aligning version by version, understanding the minimum requirements of the adopted version can have significant effects on control devices requirements, control strategies and sequences of operation.
At the end of the SD phase, the CIN should be a thorough outline of the system and the design team should solicit feedback and approval of the approach by the owners and/or users. The SOO is typically not defined during this design phase.
The design development (DD) phase is the most critical time in the development of both the CIN and the SOO. During this time, the designer will detail out all the spaces in the project and may further describe each space’s intent. During SD, the CIN may indicate that conference room lighting controls shall integrate with the mechanical systems.
During the DD phase, this requirement may be refined to indicate that the office lighting controls shall integrate to the building’s building automation system (BAS) through occupancy sensor dry contacts for demand control ventilation. The CIN may also detail the differences between large and small conference rooms as well as ones that have integration with shades and AV systems. If the conference room has multiple zones, such as general lighting, conference table pendant and perimeter wall-wash, the designer should detail out how those different zones may be triggered.
DD is also the phase when the SOO starts to detail the system requirements as outlined in the CIN. Each space within the CIN should have a corresponding space in the SOO. At this stage in the design, it may be too early to define exact thresholds and setpoints, but the structure of the SOO should be set up to easily include those later.
In the above multiple zone conference room example (see Figure 2), the SOO may define each zone with multiple setpoints and use a placeholder for the precise values:
- General lighting: a: 0%; b: x%, c: y%; d: z%; e: 100%.
- Conference table pendant: a: 0%; b: x%, c: y%; d: z%; e: 100%.
- Perimeter wall-wash: a: 0%; b: x%, c: y%; d: z%; e: 100%.
Just as during the SD phase, it is important that the owners and/or users review and provide feedback and ideally approval, of both the CIN and SOO. If the design team works closely with the owners and/or users during SD and DD, the CIN should be essentially complete at this point and the SOO should not need major revisions.
In the construction documents (CD) phase, the SOO turns into a contractually enforceable document. At this point, the exact requirements for each space shall be detailed and aligned with all other documentation such as the specifications, system diagrams, zoning requirements and panel or relay schedules.
If the design team has worked closely with the owners and/or users, this phase should mostly consist of further detailing out each space. If major changes arise during the CD phase, it is important that the OPR is referenced for compliance and the CIN is updated to align with the new direction.
The CD phase is also the last chance to verify that all sequences meet the minimum requirements of the locally adopted energy code. At the end of the CD phase, the CIN, SOO, drawings and specifications shall be in full alignment and the owners and/or users shall approve the complete set of documents before bid and construction.
Lighting control strategies
Section 5 of ANSI/IES LP-16-22 details several common control strategies, both by strategy and by space type. Within the text, examples are provided for both the CIN and the SOO. It is not the intent of the standard for a designer to copy these examples verbatim but use them as a reference and to tailor them to a specific project.
By reviewing the examples, a designer can understand the difference in language and level of detail between the CIN and SOO. Although not exhaustive, the standard does reference several control strategies, such as high-end/low-end trim, emergency response, room partitioning and spectrum adjustment that may not be found in every project type and therefore provide a level of detail that a designer may not arrive at when first considering how to develop those strategies into the CIN and SOO.
For this reason, it is important to reference the standard for guidance and examples on each new project.
Integration with other systems
As lighting control systems become more sophisticated, some can control or interface with other building systems such as AV, HVAC, security systems or motorized window shade controllers. This interface often involves multiple contractors working together to realize the design intent.
Components that allow for communication with the lighting control system and implementation of the lighting control SOO are not part of the lighting control package, such as touch-panels, thermostats, network switches or communication gateways. When components that interface with other systems are part of the lighting control package, the contractor and integrator need to fully understand what needs to be communicated and how, to achieve the desired functionality.
Clear, concise and complete documentation is necessary, to ensure that all parties understand their scope of work and how the systems need to communicate to achieve the desired result. Section 6 of ANSI/IES LP-16-22 provides examples of how these other systems may integrate with the lighting control system, which system initiates an operation and how each system shall respond.
Lighting control matrix
For large projects with complex control strategies or significant quantities of differently controlled spaces, a written SOO included in the specifications may be the best way to document the lighting control functionality. For many projects, however, having as much information in the drawing set is the best approach to ensure the contractor, manufacturer and integrator have the complete picture. This is where a lighting control matrix can provide a complete and concise representation of the design intent.
The lighting control matrix should still consider all the elements of the SOO. This may require the lighting control matrix to evolve through the design phases to not appear incomplete. For example, in may be useful to include the matrix in an SD drawing set to cover control intent for preliminary pricing but at this point, setpoints and scenes may not yet be defined. To avoid incorrect information or blank cells, it may be advantageous to hide some columns of the matrix, bringing them back at later phases when the intent has been developed.
Section 7 of ANSI/IES LP-16-22 outlines four phases of documentation (SD, DD, CD and installation and commissioning) and provides example matrices showing the necessary information at each phase.
Note: By the fourth phase, the matrix should have just as much information describing the functionality of the control system as a written SOO included in the specifications. The matrix may include a long list of keynotes to clarify intent that does not fit nicely in a matrix cell.
Integrating lighting controls
Through a detailed process of defining the control intent and translating that intent into a clear and contractually enforceable SOO, the lighting controls system designer can provide documentation to ensure the lighting control system is designed, installed and programmed as required to meet the needs of the space and its users.
Working with the owner, user and/or architect to define how a space should behave and then detailing that behavior in the construction documents into a system that the contractor, integrator and commissioning provider shall turn over will result in a system that is easier to install, use and maintain; is more energy efficient; and complements the architecture and lighting design of the space.
ANSI/IES LP-16, a consensus-based reference standard, is a tool that every lighting controls system designer should use and reference for every project to simplify the design and documentation of the lighting controls system. As control systems become more complex and more building systems become integrated with lighting controls, ANSI/IES LP-16-22 and its future revisions will be an indispensable tool of the design process.
- Understand the difference between the control intent narrative and the sequence of operations and how they are used.
- Identify different standardized control strategies and learn to integrate their requirements into design and construction documents.
- Understand how to use a lighting control matrix to simplify lighting control sequence of operations.
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