Thermal Insulation Options for Metal Buildings

Thermal Insulation Options for Metal Buildings

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Mohammad Arif KamalAn energy efficient building envelope contains both a thermal barrier and an air barrier. The key to an effective thermal barrier is proper installation of quality insulation products. Metal, commonly used in building construction, lacks the ability to naturally insulate itself, like rubber. Insulation drastically lowers the amount of money spent on heating and cooling a building by lowering the amount of heat or cool air needed. Metal Building Insulation improves the energy efficiency of the building, reduces transmission of exterior sound to the interior of the building and absorbs reverberating sounds within the building. By reducing the amount of energy spent heating and cooling households and buildings, insulation is in turn reducing pollution, like carbon dioxide emissions. It is difficult to characterize insulation because many materials come in a variety of forms. The insulation industry continues to develop new products to meet the increasing demand for specialized products. But generally the most common insulation is of the following two types:

Fiber Insulation

–    Fiberglass products come in batt, roll and loose-fill form, as well as a high-density board material. Many manufacturers use recycled glass in the production process. Fiberglass is used for insulating virtually every building component, from foundation walls to attics to ductwork.
–    Cellulose insulation, made from recycled newsprint, comes primarily in loose-fill form. Loose-fill cellulose is used for insulating attics and can be used for walls and floors when installed with a binder or netting. Because of its high density, cellulose has the advantage of helping stop air leaks in addition to providing insulation value.
–    Rock and mineral wool insulation is mainly available as a loose-fill product. It is fireproof and many manufacturers use recycled materials in the production process.

Foams

–    Extruded polystyrene (XPS), a foam product, is a homogenous polystyrene produced primarily by three manufactures with characteristic colors of blue, pink, and green.
–    Polyisocyanurate and polyurethane are insulating foams with some of the highest available Rvalues per inch. They are not designed for use below-grade, unlike the polystyrene foam insulation products.
–    Open-cell polyurethane foam is used primarily to seal air leaks and provide an insulating layer.
–    Polyicynene foam, used primarily to seal air leaks and provide an insulating layer, is made with carbon dioxide rather than more polluting gases, such as pentane or hydro-chlorofluorocarbons (HCFC), used in other foams.

Insulation and the Environment

There has been considerable study and debate about potential negative environmental and health impacts of insulation products. These concerns range from detrimental health effects for the individual installer to depletion of the earth’s ozone layer. Concerns exist when the individual installer breathes in fiberglass and mineral wool fibers; as yet, there is no accepted universal proof that either is a carcinogen. Using cellulose raises flammability issues. However, fire retardant chemicals are added to cellulose; this, along with its greater density, provides the same or greater fire safety when compared to other insulation products. For years, foam products contained CFCs, which are the blowing agents, which helped create the lightweight foams. CFCs are quite detrimental to the earth’s ozone layer. Blowing agents now used are pentane, HCFCs or carbon dioxide.

Expanded polystyrene uses pentane. Pentane has no impact on the ozone layer, but has been implicated in increasing smog formation. The insulation materials of extruded polystyrene, polyisocyanurate and polyurethane use primarily HCFCs. These are 90% less harmful to the ozone layer than CFCs. Some companies are moving to non-HCFC blowing agents. Finally, open-cell polyurethane uses carbon dioxide as a blowing agent. The carbon dioxide does not affect the ozone layer unlike other blowing agents.

Thermal Insulation Techniques for Metal Buildings

Metal and steel buildings may be durable, but this choice of construction materials also presents a challenge when looking for insulation to use on such buildings. Choosing the right insulation for a metal building kit helps to reduce energy consumption and, in some states, allow those constructing the building to claim tax incentives for making the effort to save energy. Steel and metal panels alone offer no protection from the outside temperature, meaning there is no natural barrier to heat and cold. Metal building insulation comes in a variety of options for pre-engineered insulation options. The most common types of metal building insulation are reflective insulation, fiberglass insulation, rigid foam insulation and spray foam insulation. Adding the right type of insulation helps to control the conduction of outside temperatures. The result will be a building that stays cooler in warmer months and warmer once the temperature drops. There are four basic types of insulation, all of which can have their place in metal or steel buildings [1].

Loose Fill Insulation

Thermal Insulation Options 1This type of insulation consists of loose fibers or fiber pellets. These fibers are blown into building cavities with special equipment. Loose-fill insulation can be more expensive, but does fill corners better and reduces air leakage. Additionally, this type of insulation provides a better sound barrier. Cellulose fiber is made from recycled newspapers that have been chemically treated to be flame retardant and resistant to moisture. This is a good option when looking to take advantage of green construction perks. Loose fill insulation is generally used in walls, attics and floors where it is applied through a moist-spray technique or a dry-pack process. Rock wool or fiberglass provides fuller coverage that is better for steel or metal buildings where it is applied using a Blow-in-Blanket system that blows the insulation into open stud cavities. Loose-fill insulation has a R-3 to R-4 value per inch. Cellulose fiber increases the insulating value by 30 percent over rock wool or other materials

Batt and blanket insulation

Thermal Insulation Options 2Mineral fiber consisting of rock wool or processed fiberglass is typically used for this type of insulation. Batt insulation is usually the most inexpensive of the insulation available for use in walls. However, it has to be installed carefully to be effective. Batt insulation is generally used in floors, ceilings and walls. Batt insulation works best for stud spacing of 16-24 inches or a standard joist. Some forms of batt insulation include a radiant barrier backing. This is especially effective in steel or metal buildings due to the lack of natural insulation. Blanket insulation comes in rolls cut to specification and batt insulation typically comes in lengths in 4-8 ft. lengths. Both forms of insulation have an R-value of R-3 per inch.

Rigid board insulation

Thermal Insulation Options 3This type of insulation is usually made from polyurethane, fiberglass or polystyrene. It can be cut to the desired thickness, increasing the insulating value from R-4 to R-8 per inch. Rigid board insulation is best for reproofing on flat roofs. It is also good for use on basement walls or as perimeter insulation in cathedral ceilings. It can also be used on concrete slab edges. This insulation needs to be covered with 1/2-inch gypsum board or other flame-retardant materials when applied to interior spaces. Weather-proof facing is required for exterior applications. Local municipalities may require additional covering.

Spray foam insulation

Thermal Insulation Options 4This type of insulation is liquid and contains a foaming agent and a polymer such as polyurethane. The liquid mixture is sprayed into walls, floors and ceilings. Spray foam insulation expands as it is applied and turns into a solid cellular plastic consisting of air-filled cells. This type of insulation is good for steel and metal buildings because it fills every space, no matter how small. This type of insulation is ideal for usually shaped designs or getting around obstructions. Spray foam insulation is more expensive than batt insulation, but provides a better air barrier. This is a major plus for metal and steel buildings. Additionally, spray foam insulation does not require caulking and other additional barriers since it is already airtight.

Fiberglass insulation

Fiberglass is usually the material of choice for insulation used in steel and metal buildings. Black or white vinyl fencing laminated on one side is usually a feature of the insulation to prevent moisture. White facing is sometimes used to counter the impact of ambient light by reflecting it away from the surface of the building. Fiberglass insulation and mineral wool insulation, in terms of metal building, provide a structure with numerous advantages. Some of these benefits include:

–    Controlled Heat Flow
–    Condensation Prevention
–    Noise Control
–    Increased Lighting Efficiency

The primary concern with proper insulation is controlling heat flow. Through proper use of fiberglass and mineral wool in metal building, the internal temperature is maintained despite external temperature. Using a vapor retarder facing can deter water from seeping into the insulation, protecting the building’s interior. Noise transmission-external noise penetrating the building and internal noise leaving the building-is greatly limited by insulation, which limits sound transmission by absorbing the reverberations. Lighting efficiency is increased as a result of laminated facings on insulation, which reflect existent light, cutting down on overall lighting costs.

Reflective Foil Bubble Insulation

Thermal Insulation Options 5The most effective form of metal building insulation to use is reflective foil bubble insulation. Foil bubble insulation for metal buildings uses a layer of polyethylene bubbles surrounded by layers of radiant barrier reflective foil that reflects radiant heat out of your metal building in hot climates and keeps the interior heat in during cold months. The bubble wrap insulation for metal buildings creates a more uniform temperature inside the metal building as well as creating a vapor barrier, eliminating condensation issues. Metal building radiant barrier and bubble foil insulation is a forward thinking alternative that uses the advantage of this natural metal insulation. Reflective bubble insulation is also unaffected by humidity or moisture, whereas fiberglass insulation absorbs water, making it an even less effective metal building insulator. Installing Bubble Insulation is very clean and easy and does not require any special clothing or breathing equipment. Installing fiberglass building insulation, however, can be very dirty, itchy and uncomfortable because of the loose fibers [2].

Thermal Insulation Options 6Benefits of using Bubble Foil Insulation for Metal or Steel Buildings:

–    Effective in extreme temperatures – both hot and cold
–    Strong but clean, lightweight and flexible
–    Eliminates condensation inside metal buildings
–    Easy installation – easy to cut and can be stapled, nailed or glued into Thermal Insulation Options 7place
–    Safe to handle with no special clothing or breathing equipment
–    Reflects 96% of Radiant Heat
–    Waterproof, Non absorbent surface

Protection from Condensation

When insulating a metal building, a vapor barrier is an important factor. Since steel conducts heat, a metal building naturally transfers heat energy in and out. This causes condensation to occur inside metal buildings when there is a significant temperature difference outside the building. Condensation is a major concern in metal and steel buildings. To remedy these problems, steel building insulation needs to use the most effective insulation material and vapor barrier. Insulation serves to protect a metal building from condensation, which can cause damage over time. Insulation creates a vapor barrier to reduce how much condensation takes place directly on the steel panels. Using Bubble Foil Insulation resolves this problem by being the most effective insulation material and vapor barrier. Another issues with a steel or metal building is humidity. A concrete foundation that is not fully cured can be a contributing factor to increased humidity and condensation. Steel or metal buildings located in colder climates can experience condensation from exposure to ice and frost. A regular pattern of freezing and thawing can cause frost to melt, drip water and produce condensation. Insulation placed around the red iron before metal sheeting is installed creates a “thermal break” between outside sheeting and internal framing to prevent condensation.

Protection from Mold

Insulation that is not properly installed may trap mold within the walls of a steel building. Improper maintenance is another common cause of mold in steel buildings. Animals and birds may damage insulation in metal buildings as they try to create a home. It is not always possible to prevent every possible cause of mold. The best defense is to be aware of what is going on inside the walls of a building. This is accomplished with regular inspections using special equipment to detect possible insulation issues. Once an issue is inspected, the area in question needs to be opened to correct the issue. This may include replacing insulation that is damaged.

Conclusion

Metal Building Insulation improves the energy efficiency of the building, reduces transmission of exterior sound to the interior of the building and absorbs reverberating sounds within the building. Any of the four basic types of insulation may be used in metal and steel buildings. The choice of materials used depends on several factors, such as where the building is located and how the overall structure is designed. Most metal buildings use different types of insulation for different parts of a building. If properly installed and maintained, a steel or metal building can be highly durable, energy-efficient and well-insulated for many years.

References

–    www.buildingsguide.com/blog/insulation-options-metal-or-steel-buildings
–    www.ecofoil.com/Applications/Metal-Building-Insulation

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