Cool metal roofing is primarily used to reduce cooling/heating loads on new construction and on retrofit roofing applications for steel buildings. The U.S. Environment Protection Agency has estimated that the use of cool metal roofing can save up to 40% cooling energy on homes and buildings.

The desirable attributes of cool metal roofing for steel buildings are:

· Durability. Metal roofs are resistant to wind, rain, hail, snow, and ice. This durability makes them superior to organic roofing materials that are easily degraded when exposed to changing weather conditions.

· Lightweight. Structural savings can be realized with metal roofing, when compared to other much heavier roofing options. For example, the weight of steel roofing panels ranges from 0.7 to 1.3 pounds per square foot, while that of asphalt shingles averages 2 to 2.5 pounds per square foot. This lightweight attribute is also an advantage specially for steel buildings located in earthquake prone areas.

· Fire Resistant. Metals don’t burn. Many metal roofs have been certified to meet Class A, B, and C fire ratings. In fact, many insurance companies offer reduced premiums due to the high fire resistance attribute of metal roofing.

· Aesthetics. Because they can be coated with various colors and patterns and they can be shaped into a wide variety of functional profiles, cool metal roofing products greatly enhance the appearance of steel buildings. They are a favorite of architects due to their design flexibility. The colors of painted metal roofing not only lengthen the life of the roofs but they can also be selected to match the exterior color schemes of the steel buildings.

· Wind Uplift Resistant. Cool metal roofing panels can be constructed to conform to the highest wind uplift rating from UL. In hurricane-prone areas, metal roofing is the product of choice, because they have demonstrated their ability to outperform other roofing products in severe wind conditions.

Source:http://www.wbdg.org/resources/coolmetalroofing.php

Metal roofing has been in existence for many centuries. Used as roofing material, metal roofing for any building is designed to provide protection from the elements, allows rain and melting snow to flow off the roof, and to keep the occupants and contents dry and comfortable. Metal roofing is popular because it is durable, recyclable, fire resistant, low weight, and low life-cycle cost.

Metal roofing products are available in a variety of metals, but for steel buildings, the predominant metal roofing substrate is metallic-coated steel panels or sheets. The choices for metallic coatings include zinc (galvanized), 55% aluminium-zinc alloy (Galvalume® ), 5% aluminium-zinc alloy (Galfan®), aluminium and lead-tin alloy (terne).

Cool metal roofing for steel buildings, improves energy efficiency by providing high levels of solar reflectance and high thermal emittance. No matter where your steel building is located, cool metal roofing can be engineered to meet the temperature requirements of the structure. For steel buildings in cold climates, cool metal roofing can provide the desired high solar reflectance and low thermal emittance. For steel buildings in hot climates, cool metal roofing can provide the desired high reflectance and high thermal emittance.

Cool metal roofing products for steel buildings include unpainted metal, pre-painted metal, and granular-coated metal. Whether they are for steep-slope or low-slope applications, these products come in a wide variety of finishes, colors, textures, and profiles.

In effect, cool metal roofing for steel buildings, saves energy and electricity costs by reducing the use of cooling and heating equipments. Steel roof panels with oven-cured, pre-painted organic coatings that include the new “cool pigment” technology still offer high total solar reflectance and high thermal emittance even if they come in darker colors.

Source:http://www.wbdg.org/resources/coolmetalroofing.php