Key Considerations in Radiant Barrier Technology

Radiant barrier technology seems to be the rage today and for good reason - it works.

The unconditioned space of a building can reach extreme temperatures. For example, in the United States, an unprotected attic can reach 165 degrees Fahrenheit (73.8 degrees Celsius) during the summer. This heat radiates into the home or office, causing the air conditioning to have to work harder to cool the building. Energy Is lost, reducing the level of energy efficiency.

Similar considerations must be given in warehouse, industrial, and storage facilities. In an environment that is already difficult to control, there are two other factors – productivity and safety. Excessive heat can lead to a reduction in the amount of time workers may spend in a space. This reduces productivity. At the same time, if management requires greater lengths to be spent working in extreme heat, the workers’ safety becomes a serious issue.

Radiant barrier and reflective foil technology has been with us since the 1920s, during which it was used in early efforts to reflect heat from homes that had no air conditioning system. In the 1940s, other commercially available radiant barrier products were made available, but it was in the 1950s that the product first gained the attention of scientists and engineers.

Clark E. Beck, who worked at Wright Air Force Base in Ohio, solved a problem for the National Aeronautic and Space Association (NASA). Astronauts needed to work unencumbered inside their spacecraft. However, the temperatures in space ranged from -273 degrees Celsius to as high as 230 degrees Celsius.

It was determined that protecting the astronauts in the cabin of their spacecraft would require traditional insulation that was more than seven feet thick. However, Beck pioneered the use of reflective aluminum and radiant barrier technology which prevented more than 95 percent of the radiant energy from entering the cabin of the capsule, keeping astronauts comfortable and safe.

The uses of that radiant barrier have spun off into the modern day work and can be seen in firefighting equipment, other types of protective clothing, and various types of insulation.

With the growing interest in “green” building, radiant barriers are increasing in use since they can substantially reduce energy costs, a fact recognized by the U.S. Department of Energy. An independent 2010 study by the group ConSol determined that radiant barrier technology sheathing is a top component to energy efficiency when building a new home.

It is estimated that radiant barrier technology, when correctly installed, can block up to 97 percent of the sun’s radiant energy from entering the home. This has been shown to reduce attic temperatures by as much as 30 degrees Fahrenheit and energy costs by as much as 17 percent.

Typically, radiant barriers are made of an aluminum sheathing that attaches to the underside of roof decking material. In the construction phase, this decking or roof panels may already include the radiant barrier sheathing, saving time and money down the road.

In the United States, standards in home building are established by the American Society of Testing and Materials International (ASTMI), which states that a radiant barrier must block 90 percent of heat energy, even though there are no government regulations that prevent or limit the claim of “radiant barrier.”

Many building owners may choose to turn to the range of paint products that claim to be radiant barriers.

However, in testing sponsored by the Reflective Insulation Manufacturers Association (RIMA), 17 ceramic or aluminum-infused paint products failed to meet the ASTMI standards. Only five of the paints tested met the lesser standard of blocking 25 percent of heat energy. In this case, they qualify for the label Interior Radiant Control Coating (IRCC), not radiant barrier.

“Be sure to do your homework before purchasing one of these paint products,” Mary Edmonston, the executive director of RIMA said. “If it’s being called “radiant barrier paint,’ beware.”

However, it is important to note that paints can provide limited protection at a lower cost than radiant barrier sheathing. However, care must be taken to follow the directions on the paint, frequently mix it to prevent the aluminum from settling, and to ensure that the proper number of coats is applied evenly throughout the attic or space.

The other key consideration, which applies to sheathing, is in terms of how a radiant barrier handles moisture during and after the construction phase.

Radiant barrier sheathing typically consists of a structural panel with a layer of aluminum adhered to the surface. Some manufacturers perforate the foil layer to protect against moisture issues. Yet this will not necessarily allow the panel to breathe, as not all manufacturers extend the perforations into the substrata of the panel.

An added challenge is that the adhesive used to apply the radiant barrier to the substrate can sometimes fill in the perforations, decreasing the ability of moisture in the panel to escape.

Those who are retrofitting their buildings, whether they are residential, commercial, or industrial, can see a noticeable difference in energy costs by installing a radiant barrier. However, it takes time and study to determine the right radiant barrier or Interior Radiant Control Barrier for a building’s particular needs.

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