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November 29, 2012 -
Today's tip is to make sure that lighting occupancy sensors are operating correctly after installation. First, the manufacturer and facility manager can collaborate on start-up and field commissioning. Commissioning begins during design with selecting the right sensor and locating it correctly on the plans.
During field commissioning, installers should verify that the wiring connecting the sensor or power pack to the power and loads is correct. They also should verify sensor placement and orientation against specifications and drawings.
Installation might require two or even three primary adjustments. Managers should coordinate this phase of commissioning with furniture placement, because occupants occasionally move furniture or equipment.
The system's time-delay setting allows installers or in-house technicians to change the amount of time before the occupancy sensor turns off lights after it perceives the room is unoccupied. Shorter time delays produce higher energy savings, but may shorten lamp life due to more frequent switching. Longer time delays avoid continual on-off cycles and brief periods when an occupant is moving very little. Manufacturers often recommend time delays of no less than 15 minutes.
The sensitivity setting allows the installer or in-house technician to determine the amount of movement that will trigger the lights to turn or stay on or to shut off. Because sensitivity relates to coverage, changing the sensitivity changes the coverage area.
A light-level setting is available with models that offer a daylight-switching feature. It allows the installer or in-house technician to delay turning on the lights if the room receives enough daylight. Managers also might specify self-calibrating sensors, which automatically adjust their delay and sensitivity settings over time. But they should be aware that nuisance switching might be common for some time while the sensor is learning.
After commissioning ends, facility managers should meet with occupants to educate them about the controls as a way of ensuring the technology’s acceptance.
University of Texas at Austin, facility condition assessment, facility condition index
ESCO, energy audit, HVAC