Guest post by C. Webster Marsh
Modern lighting control systems require a lot more components than they used to. As a result, a lighting controls designer’s job has come to include the documentation required to fully specify a system, which includes well-defined devices, narratives, and sequences. This column is the first part of a multi-part series that hopes to identify how lighting controls interact with each other and how best to implement a documentation style that is shared with current industry trends.
This first part will look at a generic office building, which is a common application for lighting controls. In this breakdown, each space has the following:
- A list of functions for how occupants will use the space. This helps communicate the intent for the space and it should align with project programming and the Owner Project Requirements.
- A visual layout of luminaires and zones. This identifies each luminaire and its colored control zone, but it doesn’t need to use colors. An effective zoning diagram only needs to identify each zone using some unique identification method (e.g. colors, zone numbers, outlines, etc.).
- A visual layout of controls devices in the space. This identifies each control device and its approximate mounting location. It’s best to provide any details about these devices that make them functionally unique from each other, such as identifying occupancy and vacancy sensors.
- A sequence of operations for the devices and zones. This communicates the intent of each control device, their controlled zones, and their hierarchy in relation to each other. In simple applications hierarchy may not be as critical, but it becomes essential in complex applications with large quantities of zones and devices.
Legend:
Janitor Closet
A Janitor Closet oftentimes will have one control zone and, depending on energy code, will make use of a wallbox or ceiling mounted vacancy sensor with a manual momentary switch to turn the lighting on.
Corridor
A Corridor rarely has manual overrides, unless timeclocks are utilized, and so an occupancy sensor for on and off functionality is all that is required for energy code compliance. More complex controls designs for Corridors will be shown in later parts of this series.
Conference Room
A Conference Room is often a multipurpose space that requires a flexible zoning scheme and multiple devices with a specified hierarchy. Because of this, the controls designer should identify an order of operations via the sequence of operations to provide a successful design. In this example, the daylight sensor functionality is dependent upon the state of the lighting and how it performs in relation to the task surface brightness. This is known as Closed-Loop dimming, since the lighting dims actively to maintain a target illuminance on the task surface, in this case the conference table.
Open Office
An Open Office can be an even more complex design scheme with a high number of zones, responding to different devices, and so communicating hierarchy is critical so as to avoid unwanted behaviors, such as daylight zones turning on when the space is unoccupied and turning off when the space is occupied and not receiving sufficient daylight. The examples shown in this part identify both Open-Loop and Closed-Loop daylight dimming. As can be seen in the graphic, Closed-Loop dimming requires more devices and zoning in order to accurately monitor and adjust the task surface illuminance. In Open-Loop dimming only one sensor per window direction is required here, since it is only monitoring daylight entering the space.
Conclusion
While these simple examples of the intricate interactions that lighting controls devices can have, hopefully they have helped communicate how effective documentation can improve one’s understanding of how the system is expected to perform. More complex examples will be forthcoming in future parts to this series, but the overall aesthetic will remain the same and will implement best industry practices.
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