Lighting for Universal Design

Lighting for Universal Design

(Parte 1 de 3)

becoming an increasingly more familiar term in our vernacular. The concept, initiated by Ron Mace in the 1970s, addresses the ability of humans to live comfortably in our built environment. How can we accommodate the needs of a broader segment of our population, in fact, the broadest segment of our population? What types of homes, buildings, and public spaces would allow almost everyone to feel comfortable, to navigate without restriction, despite any physical or sensory impairment? What types of spaces would just make life easier for those of us who are getting older, or even the very young among us?

Aging-in-place is a popular phrase used by the National

Association of Homebuilders (NAHB) today. An eponymous CBS News segment recently showcased a family of multiple generations, right up to the great grandmother, all living together in close quarters, under one roof. This is becoming more and more common. Remember when we “baby boomers” were growing up in urban neighborhoods as children? Children, parents, grandparents, aunts, uncles, and cousins often lived within a few blocks of each other, if not in the same apartment building across the hall from one another. There wasn’t a day that went by when we didn’t see each other, at least once. Everyone’s door was open at any time to family and neighbors. We didn’t need to make special “plans” to visit, no one had to check their calendar; we just walked right in. The coffee pot was always ready and perking on the stove, and some freshly baked cake or biscotti was just coming out of the oven, or homemade tomato sauce bubbling in the pot, ready for that crust of Italian bread to dunk. Life was simple. We took care of each other. “Nursing home” wasn’t in our vocabulary.

That culture was lost to most Americans over the past few decades, but now there is a desire to return to that simple life. People resist being placed in “assisted-living facilities”; no one wants to leave their homes. We yearn to have family around to take care of us once again. So, homes are being built for “sandwich” generations. Master bedrooms, as well as bedroom suites for grandparents, are appearing on the first floor. Doorways and hallways are wider to accommodate any peripheral walking or wheelchair devices we may need, or just to allow large pieces of furniture to be moved easily. Front entries are step-free, and thresholds throughout the house are smooth. Door handles are levers, not knobs, and microwaves are low enough that even a not-so-tall person can reach them.

So, physical barriers are being mitigated. Now, how do we navigate these spaces? First of all, if we are sighted, we need to see. Lighting is the key element. If we aren’t sighted, we need to orient ourselves.

Light––Or Lighting?

Have you ever thought about the difference between light and lighting? Lighting is the application of light. We have endless means of creating light these days––windows, for one; then, we have a variety of lightbulbs, thousands of decorative luminaires, and more popular than ever––the return of the candle. What we do with these tools, where we place them, how much area we light with them, what color “white” light we choose, what shadows we cast, or which artwork we accent ––the effects we create––this is lighting. As in the theatre, we evoke emotion through lighting. Although we are generally unaware of it, we design our lighting every day. Lighting has an infinite capacity to improve our living environment, visually, aesthetically, and functionally. With energy in high-crisis mode today, lighting responsibly is our duty. And, fortunately, designing lighting that respects energy limits aligns perfectly with lighting that benefits young eyes, aging eyes, and everything in between.

The Aging Eye

With all the good things that come with aging––wisdom, character, personal and professional accomplishments––so come the not-so-good things. Our vision deteriorates dramatically through the normal aging process. Before age 65, we undergo optical changes, and after age 65, neural changes.

Optical Changes

The retina, which is actually part of our brain, is a network of cells that includes photoreceptors, or light detectors, located at the rear lining of the eye. Increasingly less light reaches the retina (reduced retinal luminance) as we age, because our pupils get smaller, a condition known as senile miosis; and our crystalline lens becomes thicker. More and larger protein molecules accumulate and scatter through the crystalline lens, causing increased stray light and disability glare, or glare that prevents us from performing our task. We also experience reduced retinal contrast and color saturation, so we don’t see images as clearly. Add to that presbyopia, or loss of accommodation, which means we cannot adapt as

DESIGN universal

Patricia Rizzo

UNIVERSAL design

Light And Lighting

Light touches every part of our lives, from the moment we are born until the moment we die, and maybe beyond. It sustains us; allows us to see; allows us to sense the time of day; to sense the season; and it regulates our 24-hour circadian clock, the sleep/wake cycle that we take for granted. We feel joy when the sun shines, and perhaps romance when the moon shines. Shadows intrigue, or frighten us; bright light protects us, makes us feel safe. Light is a constant companion.

In this article, I intend to talk about lighting, specifically lighting for universal design. You’ve no doubt read about universal design in previous issues of Ultimate Home Design. Universal design is synopsis

Lighting is the application of light. What we do with lights, where we place them, how much area we light with them, what color “white” light we choose, what shadows we cast, or which artwork we accent––the effects we create––this is lighting.

As we get older we need more light, but it must be more shielded, balanced, and uniform light.

Lighting that is the most effective for an application while using the least amount of energy can be considered energy-efficient.

Lighting for universal design is lighting that grows and shrinks as we do; it lives with us, and adapts to our needs.

(Figure 1) Conceal light source within opaque shade (left) or diffuse glass (below) to protect eyes from glare.

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“Designing lighting that respects energy limits aligns perfectly with lighting that benefits young eyes, aging eyes, and everything in between.”

Energy-Efficient Lighting

A frequent misconception is that energy-efficient lighting equals fluorescent lighting. More accurately, lighting that is the most effective for an application while using the least amount of energy can be considered energy-efficient. In certain instances, that may mean that even your basic incandescent bulb is the most “efficient” for your purposes.

Let’s define efficiency in absolute terms. Efficiency is a term typically used to describe the performance of a lighting fixture, or luminaire, and is expressed as a percentage. For example, a linear fluorescent pendant used in an office may have an efficiency of 76 percent. This takes into account the efficacy of the light source itself, in this case the fluorescent bulb and the light loss due to absorption or entrapment by the fixture. Luminaire efficiency is the ratio of the light output emitted by a luminaire to the light output emitted by the lamp-ballast combination (Rea, 2000); it indicates how much of the lamp’s light output the luminaire’s optical system directs out of the luminaire.

How about efficacy? An awkward word, but that is the metric used to describe the number of lumens emitted by a light source for every watt of energy consumed. Think of it the way you would consider miles per gallon (mpg) in the automotive world. Lumens per watt (lm/W) indicate how efficacious a lightbulb is in absolute terms. The incandescent bulb, which has been with us since 1879, is still going strong; it averages 14 lm/W. However, only about 10 percent of the energy consumed by an incandescent lamp results in radiation that is within the visible spectrum, or seen as light, while the other 90 percent is radiated as heat.

Fluorescents

Linear fluorescent sources, the long tubes we’re used to seeing in industrial fixtures, and often relegated to the garage and basement, average 80 to 100 lm/W. These sources, such as T5 (5/8 of an inch in diameter) and T8 (8/8 of an inch, or 1 inch in diameter) now use a rare earth tri-phosphor coating in their glass envelopes, vastly improving the color they emit and their ability to render color (such as your skin tone, or your drapery fabric). They operate on electronic ballasts instead of the heavier, noisier, flicker-causing magnetic ballasts we’re familiar with, making them even more efficient and less obnoxious. The hum and buzz, and greenish color, so long associated with fluorescents has virtually vanished.

Compact fluorescent lamps (CFLs) are the smaller variety designed to replace incandescent bulbs. They come in shapes resembling ice cream twist cones and short bent tubes. They may have a screw base for standard luminaires or a pin base that requires a dedicated socket. CFLs have

DESIGN universal

(Figure 3 Above) Valance conceals linear fluorescents providing soft ambient light and eliminating the need for downlights. (Figure 3b Right) Cove is designed to extend from columns, blending into architecture, and provides soft, indirect lighting for passage in hallway.

glare, and a reduced ability to adapt to large changes in brightness. So what would alleviate these transitions?

Lighting Solutions

As we get older, we need more light, but it must be more shielded, balanced, and uniform light. A few tips include:

• Avoid direct glare caused by exposed lightbulbs. Place some kind of translucent material between you and the light source if you can see the lightbulb while standing or sitting. Select luminaires with some type of shade or diffuser (Figure 1).

• Avoid glossy surfaces, especially on floors or countertops; they become mirrors, reflecting the brightness of the light source and increasing the impression of glare. • Avoid placing bright luminaires against dark ceilings.

• Use indirect lighting whenever possible; it fills in the shadows and creates a soft, glare-free environment while seeming brighter than a directly lit environment (Figure 2).

• Conceal linear fluorescent luminaires behind a decorative fascia, creating a cove or valance. This works especially well when you have nine-foot ceilings or higher, allowing the light to wash the walls and ceilings so your room surfaces become an extension of your light source (Figure 3).

• Use light color finishes on walls and ceilings to soften the effects of bright light sources and to reduce shadows.

• Avoid making the interior of your home too dark compared to the exterior; use dimmers to balance the brightness of your table lamps, floor lamps, and chandeliers. Balancing light levels within spaces and between adjacent spaces is important, since our accommodation is reduced. We can’t negotiate sharp transitions from bright to dark spaces and vice versa as easily.

• Provide good contrast between transition areas. For example, around a doorway, lighting horizontally and vertically around a door jamb is a helpful cue for someone who has a hard time focusing clearly. During the day, contrasting paint colors between wall and door jamb will work well, but illuminated delineation is needed at night. Think about waking up in the middle of the night and trying to orient yourself to the room configuration. Light that is just bright enough to enable you to see and guide you to where you want to go, without being so bright as to disturb you, is very helpful––a type of large area night-light.

• Maintain uniform illumination where possible. Oftentimes the way recessed or track lighting is located creates scallops of light on our walls or floors. These patterns, or pools, of light can be confusing and disorienting (Figure 4).

• Place more light close to the task. If you are writing at your desk, place your desk lamp opposite your writing hand to avoid working in your own shadow. This is true with overhead lights as well. In your kitchen, make sure the downlight over your sink or stove is in front of you, not over your shoulder.

DESIGNuniversal quickly to sharp changes in brightness, and there you have it: the mandatory optical change package that we are forced to live with. And that’s the good news!

Neural Changes

After age 65, our neuron density is reduced. Fewer neurons means limited image enhancement, reduced visual field, and photophobia, or discomfort glare. Diseases such as the following become more common: • Cataracts––an opacity developing in the lens

• Glaucoma––progressive and visual field loss as the result of a number of diseases that affect the eye

• Macular degeneration––changes to the pigmentation in the macular, a circular yellow-pigmented area of the retina, 2 to 3 millimeters in diameter

• Diabetic retinopathy––results from chronic diabetes mellitus, which effectively destroys parts of the retina through the changes it produces in the vascular system that supplies the retina (Boyce, 2003)

What this all means is that we don’t see as well. Less light reaches the retina; there is reduced retinal contrast and color saturation, loss of accommodation, increased sensitivity to

(Figure 2) Linear fluorescent lights above and below cabinets fill in shadowsand increase the impression of brightness while producing a glare-free environment.

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Energy-Efficient Lighting, The Aging Eye, And Universal Design

Revisiting the issues that characterize our visual needs as we get older, we know we must respect glare, accommodation, orientation, and way-finding; and we must minimize equipment replacement in order to avoid climbing ladders, thus inviting accidents. Here are some ways fluorescent and LED sources comply:

Fluorescent Sources

Linear fluorescents make wonderful indirect sources, addressing many of the aging eye issues. They cover a greater area than incandescent sources; linear fluorescents lend themselves to architectural applications such as coves and valances. They can provide soft indirect lighting that fills in shadows, minimizes glare, and utilizes the room surfaces as light sources, while being easily concealed behind decorative moldings. Both linear fluorescents and CFLs have a higher efficacy than incandescents, emitting approximately 4x as much light for equal wattage consumed, which translates to one-fourth of the operating cost. They live approximately 10x as long as incandescents, so they require less frequent replacement, which saves money while reducing the risk of falls. CFLs are extremely well suited to table and floor lamps, as well as sconces if housed within a diffuse or colored shade.

(Parte 1 de 3)

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