Mar 15, 2018

Quality lighting touches all corners, from our homes to our seniors
By Willard Warren

Here’s some “what’s new” in energy conservation and safety. Recent satellite photos reveal that sky glow at night is increasing in developing areas from new buildings, bright signage and newly paved roads lighted by LEDs, which all send direct and reflected light skyward. Streetlights should certainly be shielded better, but bright signage is a cultural favorite, especially in Asia. In New York, the city will soon require that every non-residential building post a sign indicating how much energy load reduction has been achieved.

Photovoltaic (PV) solar panels have dropped in price, and their efficiency has increased to where each sq ft is capable of generating up to 15 watts of AC or DC power. Low-rise buildings with a high fraction of roof area divided by wall area are good candidates for the installation of PV roof panels for site-generated renewable electrical power. Wiring the PV panels in series to reach 48 volts allows you to connect them directly to DC lighting loads using NEC Class 2, plug-and-play circuits at a much lower installation cost. Replacing screw-in incandescent lamps with screw-in LEDs will reduce load by 80 percent. My co-op, with its 400 apartments on a master meter, has given us up to 10, 10-W screwin LEDs, to replace our existing incandescents—a win-win for both.

In non-residential buildings, obsolete T12 fluorescent lamps, driven by equally obsolete magnetic ballasts, can be replaced by tubular LEDs (TLEDs) to cut load by at least 50 percent, by using one of these four measures: 1) Replace the existing luminaires with new LED units; 2) Replace T12 fluorescent lamps in existing units with UL listed Type (A) TLEDs, one for one. (Warning: Leave the magnetic ballasts in the circuit, but they will fail someday, so make sure that the TLEDs that replace the T12s will be compatible with the new electronic drivers that replace the failed magnetics.) A threelamp luminaire will likely need only two TLEDs to meet or beat the illuminance level of the three T12s; 3) Discard the T12 lamps and the magnetic ballasts and install UL listed Type (B) TLED lamps—each has its own internal driver, so connect the sockets directly to the power line; 4) Upgrade the existing luminaires with UL listed Type (C) TLEDs, and new external drivers, reflectors and sockets.

According to long-term studies done by both the NeuRA Foundation and Shell Point Retirement Community, the leading cause of accidental death among seniors, 65 and older, is from falls (onethird of all elderly people). One reason they fall is that their field of vision shrinks as they age and their peripheral vision, connected to their autonomous nervous system, no longer “sees” hazards in their path to alert them. The Number 1 warning in the NeuRA Foundation’s What We Know report for “Falls Prevention for Seniors” reads: “Make sure that lighting is not too dim or too direct and that light switches are easily accessible.” LED light sources are easily dimmable and should be installed in every bathroom and bedroom in residences, hospitals and nursing homes.

Seniors do not need total darkness to be able to fall asleep. TV news clips often show scenes where seniors have crashed their cars into homes, trees and gates at night. Eyes can play tricks in dim light while glary oncoming headlights can momentarily blind a driver. When going at only 30 miles per hour (44 ft per second) you need ¾ of a second just to hit the brakes, by which time you’ve traveled 33 more ft, before the brakes take hold. Direct glare and too-low light levels at night are “killers” for seniors.


Willard Warren

Willard Warren

Willard L. Warren, PE, LC, Fellow IES, DSA, is principal of Willard L. Warren... More info »