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Insulation Systems and Vapor Retarders

Inside Insulation: Providing Superior Performance and Easy Installation

Heat moves toward cold. This is the basic idea behind all insulation products. By reducing the transfer or flow of heat, corporate conglomerates and homeowners alike can reduce their heating and cooling bills and increase the overall comfort of their buildings.

There are three modes of heat transfer: convection, conduction and radiation. Convection is the transfer of heat through moving air currents such as wind. Conduction is heat flow through a solid object such as a skillet on a stove. Radiation is the transfer of heat energy through infrared light waves. The best example of this is the sun. Light waves from the sun radiate to Earth and heat up the surfaces with which they come in contact. You cannot see these light waves, but when you step into the sunlight, you can feel them warming your skin.

The best way to prevent the transfer of heat from convection is by sealing all air infiltrations into the building. Testing completed by the Florida Solar Energy Center, Cocoa, Fla., stated that for an average 1,500-square-foot (139-m2) home in central Florida, infiltrations made up 10 percent of the home's heat gain/loss.

Typical mass insulations such as fiberglass or cellulose are used to slow the rate of heat transfer through conduction. Heat moves through these products at a slower rate than they would through another material such as wood or metal. The value used to measure the rate of heat transfer in these products is an R-value. The higher the R-value, the greater the resistance to heat flow.

Understanding radiant heat and corresponding insulation is slightly more technical. Radiation is a light wave and has no temperature. When these light waves strike a surface of a material, they transfer energy to the molecules of that material causing them to move faster and heat up. The terms used to describe the transfer and absorption of radiant heat are emissivity and reflectivity. Emissivity refers to the ability of the material to allow radiant heat to pass through. Reflectivity is the amount of radiant heat reflected or not transferred from a material. Emissivity and reflectivity are proportional. If a material has an emissivity of 0.85, then it has a reflectivity of 0.15. For example, wood has an emissivity of 0.9 and a reflectivity of 0.1, meaning it absorbs and transfers 90 percent of the radiant heat. Reflective insulation and radiant barriers reflect at least 90 percent, or 0.9, of the radiant heat and only allow 1 percent, or 0.1, of the radiation to transfer.

When architects select building insulation for a project, they do so based on the needs of their client (energy cost savings, comfort or aesthetics). Then they evaluate the building insulation options for the specifi c type of application-as in the case highlighted below, a metal building with little or no insulation. In addition, the architect may have an interest in seeking out products that could qualify the client's building for green building certification (LEED for Existing Buildings).

When selecting any type of insulation, the architect should always thoroughly review technical data, samples, installation sheets and product warranties. And they should work directly with the manufacturer to obtain a list of qualified installers in the location of the project.

 

Iron Works Fitness, a 20,000-square-foot (1,858-m2) fitness club in Hueytown, Ala., was looking to reduce air-conditioning costs and increase the comfort level of their patrons during hot Southern summers. Radiant heat emitted from the uninsulated metal roof down into the building, conductive heat worked its way throughout the building and convective heat infiltrated the building through small seams in the building envelope. Iron Works needed an effective solution to save money and minimize the fitness centers down time.

Iron Works decided to upgrade its insulation system with more than 10,000 square feet (929 m2) of Auburndale, Fla.-based Fi-Foil Co. Inc.'s RetroShield System. Installed by Energy Home Shield of Ocala, Fla., this exclusive system resulted in an approximate 15 to 20 percent reduction in monthly electric bills along with a cooler, more comfortable building. This reflective insulating system sealed off the air infiltrations, added an R-value of R-16 to the ceiling and reflected 97 percent of the radiant heat away from the building. And as an additional benefit of the simple installation process, Iron Works did not have to close for this retrofit. The owner is also able to maintain comfort at a 74 F (23 C) setting as opposed to 72 F (22 C) prior to installation.

According to Iron Works Fitness Owner Terry Brasseale, he wanted to find an affordable and efficient way to reduce his air-conditioning costs. "Our electric bill was $5,400 during the month of July. I had RetroShield installed in August, and our electric bill went down to $4,700. By September, our electric bill had declined to $3,400." Brasseale noticed another added advantage to having RetroShield installed. "We've even noticed that the amount of dust that accumulates on the gym equipment has reduced."

 

Matt Struss is corporate sales and marketing director for Fi-Foil Co. Inc., Auburndale, Fla.