Specifying Flooring to Maximize the Benefits of Light

By Susan L. Monroe

It has been proven that exposure to sufficient levels of light in healthcare facilities — daylight or bright artificial light — has a strong positive impact on the patient experience, aiding in wayfinding, promoting comfort, mental wellness and physical healing, and reducing the length of stay in hospital for some. Lighting has its benefits for healthcare staff, too. It has been found to increase job satisfaction, contribute to adaptive circadian rhythms, lower stress, improve mood and decrease the potential for medical errors. Given this, it is important to incorporate flooring with high light reflectance values (LRVs) into hospital spaces to help harvest natural sunlight and increase illumination.

Visual Comfort and Glare
All materials reflect light. Light-coloured floors reflect more light than dark ones. And smooth surfaces reflect light directly, while textured surfaces scatter the light causing it to be less bright in one area. When a large amount of light is directionally reflected, glare can result. The eyes perceive glare when the luminosity in the visual field is greater than that which they are adapted. This can result in discomfort, visual impairment or both.

There are two types of glare: direct and indirect. Direct glare results when a high light source like the sun is present in the field of view. Indirect glare is caused by the reflection of high brightness on a polished surface, such as the reflection of the sun off a mirror. Smooth surfaces are more likely to cause direct glare than textured surfaces.

In most healthcare settings, flooring with textured, non-glossy or matte finishes are preferable to highly polished surfaces. This is especially true in senior or assisted living facilities. With age, less light reaches the back of the eyes, pupils get smaller and the lenses inside the eyes become thicker, absorbing and scattering more light and adding a ‘luminous veil’ over images on the retina. These vision impairments raise safety concerns for seniors. They reduce the contrast and sharpness of objects, vividness of colours and require considerably more light for seniors to see properly than their younger counterparts. Because those 65 and older need higher light illuminance, freedom from glare and enhanced luminance or chromatic contrasts, flooring surfaces in corridors and common areas of senior living facilities should not contain strong or highly contrasting patterns nor highly reflective flooring.

Flooring Light Reflectance Values
Bright spaces aren’t just about light sources — they are about integrated systems. The use of flooring with high LRVs increases operational efficiencies in a healthcare facility by maximizing the inputs of the artificial and natural light sources to increase illumination in the space without the use of additional energy. In fact, the use of flooring with high LRVs can decrease artificial lighting needs resulting in energy cost savings.

Traditionally, it has been believed that wall and ceiling reflectivity more significantly impacts the luminance of a space than flooring, but research indicates flooring is an effective surface for efficiently reflecting light.

While hospital beds, equipment and patient room furniture do cover areas of the floor, they do not provide complete coverage nor interfere with the floor’s ability to reflect light any more than curtains and mounted equipment impede the reflectivity of walls against which they are placed.

LRV is the total quantity of visible and usable light reflected by a surface in all directions and at all wavelengths when illuminated by a light source. LRVs of flooring and other surfaces significantly impacts both natural light and artificial lighting distribution within a space. On a scale from zero to 100 per cent, a LRV of zero represents total surface light absorption and 100 indicates total light reflection. When higher reflectance flooring is used, more light, from all sources, is reflected back into the space and luminance levels are increased. Rather than adding more lighting assemblies or increasing the intensity of existing units, utilizing light reflective surfaces is a cost-effective way to improve illumination.

The Illumination Engineering Society of North America recommends that LRVs for flooring be 20 to 30 per cent in operating rooms. Flooring products that have at least a 25 per cent surface LRV can contribute to LEED credits.

A recent study by Pennsylvania State University looked at the impact of flooring with high LRVs on the operating lighting energy and lighting quality in a healthcare setting, such as a hospital or medical facility. The study covered four different types of spaces: a corridor, patient room, exam room and cardiac catheterization lab. In each of these settings, researchers assessed the horizontal and vertical illuminance levels of a representative area of the spaces. Horizontal illuminance is the amount of light falling onto a horizontal surface like the floor, and vertical illuminance describes the illuminance landing on a vertical surface, such as a wall.

For the study, lighting conditions in each of the settings were measured for floor reflectance values of 10, 30, 45 and 60 per cent; wall reflectance values of 20, 40, 60 and 80 per cent; and ceiling reflectance values of 60 and 80 per cent. Differences in the average values were evaluated to determine the potential for energy savings as the floor reflectance changed, relative to the expected performance with a 20 per cent reflectance floor. Study results indicate as the LRV of the flooring increased, so did the illumination levels of the spaces. The findings conclude that higher reflectance flooring can increase illuminance levels for a given lighting system, reducing energy consumption and resulting in energy savings for a space design that is finely tuned to achieve a specific target illuminance level.

The lighting improvement will be more substantial in spaces that have higher reflectance ceilings and perimeter walls. As the study shows, illuminance increases steadily as illuminance of ceilings and walls increases. The greatest increases in luminance occurred in spaces where the ceiling and walls had reflectance values of 80 per cent. It’s not so much the lighting or the light source that effectively increases luminance but the amount of light available for the space. This can be increased from floor reflectivity.

Reducing Energy Costs
Lighting is one of the single largest consumers of electricity in hospitals, representing an average of 16 per cent of total energy consumption and about 27 billion kilowatt hours or 43 per cent of annual electricity use. Specifying flooring with high LRVs provides opportunity to reduce energy costs by maximizing available light throughout a space.

To ensure light is sufficiently reflected, select lighter coloured flooring. Avoid extremely dark coloured flooring materials as these surfaces can require more installed lighting power to meet illuminance levels, resulting in higher costs. Reflectance will vary based on the type and colour of the surface.

In a hospital corridor, where the LRV of flooring material was raised from 20 to 30, 45 and 60 per cent in the Penn State study, electricity savings amounted to between three and 22 per cent of the lighting energy that would otherwise be consumed depending upon the reflectance of the ceiling and walls.

Wall reflectance can increase the interreflections within a space, which has a significant impact on high reflectance flooring. When the wall reflectance is 80 per cent versus 40 per cent, the savings between a 20 and 60 per cent reflective floor more than doubles.

Final Insights
While healthcare facilities are lit by a combination of electric lighting and natural daylight, there is a strong preference for daylight. Electric light is needed throughout all parts of the building to illuminate spaces where natural light cannot be present. However, the need for artificial lighting can be reduced, not only by efficient utilization of sunlight wherever possible but by the use of flooring with high LRVs. Through the use of daylight, which is delivered at no cost, and flooring with high LRVs, healthcare facilities can improve patient outcomes and staff performance and reduce their electricity usage, positively impacting the facility’s bottom line.

Susan L. Monroe is director of environmental, health and safety, and product stewardship and quality at Armstrong Flooring, a leading global manufacturer of flooring products. She can be reached at [email protected].

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