Application Issues With Lighting Control Systemstest

By Craig DiLouie

November 2015

Fully realizing the value of lighting controls requires proper application. This process involves gathering information about the application, complying with energy codes where applicable, taking advantage of available rebates, and choosing the most appropriate equipment based on the application and physical limitations to installation.

Before planning a lighting control upgrade, managers should conduct a walk-through of the building to evaluate control opportunities and needs. The goal is to identify visual needs, occupancy patterns, areas of ample daylight, energy use and physical limitations. Lighting audits that use data loggers to measure lighting use can provide detailed, useful information.

Managers also must consider code issues. Most commercial building energy codes require that a new device replacing a lighting control device must comply with the code’s lighting-control requirements. Energy codes based on ASHRAE/IES Standard 90.1-2010/13 require compliance with automatic shutoff lighting control requirements if 10 percent or more of the connected lighting load is replaced as part of a lamp-ballast or light fixture upgrade. Managers should check the local code to understand the requirements that apply to a project.

As for rebates, active commercial lighting rebate programs cover more than 70 percent of the United States. These rebates reward energy efficiency with a cash payment that can significantly reduce the cost of installation and make the investment more attractive.

Existing building applications

Seventy percent of lamps in existing institutional and commercial buildings are not controlled by a manual dimmer or automatic light-reduction or shutoff device, according to the U.S. Department of Energy, presenting managers with major opportunities for energy savings.

For spaces that are consistently occupied, managers should consider time-based controls. This approach involves installing lighting control panels with time-clocks next to the circuit breaker panel or upgrading the panel itself to programmable circuit breakers. For intermittently occupied spaces, managers can consider occupancy sensors and interval timer switches. In spaces with ample daylight, consider daylight harvesting controls, which involves installing photosensors and, where applicable, dimmable lighting.

The primary challenge to incorporating advanced lighting controls in existing buildings are physical limitations related to installing new wiring. When installers must use existing wiring, a good first step is to install wall-switch replacement controls, such as occupancy sensors, and use power line carrier technologies, such as line-voltage dimming ballasts. Some control systems feature a line-voltage conductor as a communication bus, simplifying wiring installation.

Alternately, managers can specify wireless controls to gain flexibility and establish allow control points anywhere within range. Another option is to replace existing fixtures with those featuring onboard controls. For example, consider installing bi-level light fixtures with integral occupancy sensors in stairwells and on the building perimeter.

When new wiring is an option — either within an accessible ceiling or within a raceway surface-mounted on an inaccessible ceiling — low-voltage wiring can connect devices within local systems and to a central point for building lighting control.

Intelligent lighting control systems are suited to existing buildings because installers can use one low-voltage wiring bus to connect intelligent devices implementing multiple strategies, which reduces cost.

With intelligent control systems, zoning and rezoning is implemented based on software, not rewiring, and zoning can be as small as individual light fixtures. Installers can calibrate the controls remotely, reducing commissioning, and the devices can report information about energy use and operating status to a central control point.