By James C. Elledge, IFMA Fellow, CFM, FMA, RPA, RIAQM
Published in the July 2008 issue of Today’s Facility Manager
Q In order to reduce our energy consumption, I have proposed installing passive infrared occupancy sensors (PIR) in places such as restrooms, conference rooms, and some offices. I calculated the return on investment (ROI) to be less than one year. The response to my proposal was instead to place labels at light switches asking everyone to turn off the lights when leaving the room. Is there any evidence that I can use to show that this suggested method will not work effectively? Can I depend on employees turning off lights simply by being asked? More important, is there any study to support the use of PIR sensors?
Magellan’s Travel Supplies
Santa Barbara, CA
A One way to approach the energy reduction issue is to show management that you are complying with specific energy rules and regulations. The new ASHRAE 90.1-2004 cuts lighting power densities several ways:
- Exit sign wattage cannot exceed five watts per face, which essentially means LED-based signs must be used.
- More spaces will need lighting controls, including occupancy sensors and timers. On the controls side, Standard 90.1 requires that all lighting be controlled by an automatic shutoff device for buildings more than 5,000 square feet, and that each room has its own control that also automatically turns off lighting. Control systems meeting these requirements can be either time based or occupancy based. Large buildings with open areas use time management systems with lighting relay panels that are either independent systems or integrated with the mechanical building management systems (BMS). For small spaces, occupancy sensors are generally more cost-effective initially and provide a higher level of energy savings in the long run.
- Task lighting is now covered in lighting power densities, though a separate allowance is provided beyond the lighting power densities for built-in lighting.
You can read about the requirements here.This could help resolve the issue of automated control (sensor) or manual operation (employees). Thanks for your question.
Elledge,facility/office services manager for Dallas, TX-based Summit AllianceCompanies, is the recipient of the Distinguished Author Award from theInternational Facility Management Association (IFMA), is an IFMA Fellow, and isa member of TFM’sEditorial Advisory Board. All questions have been submitted via the “Ask TheExpert” portion of the magazine’s Web site. To pose a question, visit this link.