4 FM quick reads on lighting
1. Planning Successful Lighting Retrofits
I'm Dan Hounsell, editor of Maintenance Solutions magazine. Today's topic is, successful lighting retrofits.
Lighting retrofits are increasingly popular because of the bottom-line benefits they offer institutional and commercial facilities. San Diego State University undertook a series of lighting retrofits in recent years, and it has specified light-emitting-diode (LED) technology for five different spaces on campus, including a lecture hall, a gymnasium, and a restroom with low ceilings that required the high-quality light that LEDs could provide.
Along with an improved quality of light, dimming capabilities in the lecture hall and the ability to run gymnasium lights at 60-65 percent capacity have contributed to the university's positive experience with LEDs, says John Eaddy, associate director of physical plant.
"Our experience has been outstanding," Eaddy says.
He has found the initial cost of LEDs to be higher than the cost of more traditional fixtures, but the reduced maintenance requirements and potential for energy savings have created a potentially lucrative payback for the university. Eaddy also looks for rebates from the state or local utility to help achieve a quicker return on investment.
"When we're going out and doing these projects, we're realistically looking for no more than a 2-1/2-year payback," Eaddy says. "We've been able to quantify and actually meet that goal, 9 out of 10 applications."
Eaddy hopes the success the university has had with T8s and LEDs for indoor applications translates to exterior applications. The university has retrofitted six parking structures with 32-watt T8 lamps and is conducting a test on the use of LEDs in campus streetlights.
Lighting projects continue at San Diego State, and contributions from the university's students will play a pivotal role, given their past interest in helping collect data for planning retrofits. As Eaddy discovered, the students' passion for working together with the physical plant department benefits the facilities, their operations and the university as a whole.
Occupancy Sensors Need Not Leave Occupants in the Dark, Shorten Lamp Life
Today's tip comes from James Piper, contributing editor for Building Operating Management magazine: Properly installed occupancy sensors won't leave occupants in the dark or reduce lamp life.
One of the biggest complaints concerning the occupancy sensor is that it can leave occupants in the dark if it falsely believes that the space is unoccupied. Most occupancy sensors work by detecting motion. Once detected, the sensor turns the lights on for a preset amount of time. Each time that motion is detected, the sensor's timer is reset. If no motion is sensed and the timer reaches its preset interval, the lights are turned off. If the space is still in use, the occupants can be left in the dark.
In most cases, the failure to detect occupants is the result of installation or application errors. To be effective the sensor needs to be able to see all or most of the space. Sensors have a limited viewing range and angle. Objects within the space or unusual room configurations can partially block the view of sensors, resulting in false readings. By selecting the right type of occupancy control and by properly placing that control, most false readings can be eliminated. If there still are concerns about leaving occupants in the dark, a single, low wattage fixture can be left switched on at all times to provide backup lighting.
A related concern is that, as a result of their frequent on off cycles, occupancy sensors kill lamp life. While there is no question that this frequent cycling does reduce lamp life as measured by total operating hours, it can actually extend the calendar life of the lamps, particularly in applications where light is only needed a small fraction of the time.
This has been a Building Operating Management Tip of the Day. Thanks for listening.
Five Lighting Maintenance Practices Can Ensure Quality
Today's tip from Building Operating Management comes from Frank Feist, a senior designer with MCLA: Keeping five points in mind can help ensure that facility maintenance practices maintain the lighting quality of a new design.
1. Don't re-lamp with lamps from different manufacturers or with different model numbers. Different color temperature lamps obviously look different, but even the same color temperature lamps from different manufacturers look different since they all use different proprietary mixes of phosphors, etc.
2. It may be cheaper to use a lower color rendering index (CRI) lamp, but it's not worth it if everyone looks like corpses. It also makes it more difficult to discern differences in colors; red especially tends to look dull and dead. In general if it has a CRI below 80, it shouldn't be used.
3. Screw-in compact fluorescent or LED lamps may fit in a fixture, but they won't provide the same quality (and sometimes even quantity) of light that the original incandescent lamp did. These fixtures are designed around a specific lamp, and reflectors can function significantly more poorly with a different one.
Very limited numbers of incandescent make it onto projects any more, and those are generally used for highly specific purposes for which fluorescent, LED or metal halide are not suited. Incandescent is less efficient, but it still has better color quality, true full range dimming, and is a point source that allows great optical control.
4. Group re-lamp if possible. It takes more effort to replace lamps as they burn out than it does to simply re-lamp all fixtures at scheduled intervals. This won't eliminate all spot re-lamping, but there will be far less of it.
5. Where wet location fixtures are used, the manufacturer may have particular instructions for re-lamping. These should be followed to avoid water ingress and fixture failure.