Insulating Against Radiant Heat

Traditional forms of mass insulation, like fiberglass, are effective in preventing heat transfer by conduction and convection, but they less effect on radiant heat. Between 80 and 90% of the radiant heat striking fiberglass will pass through or be "emitted". Radiant transfer typically has as much impact on the temperature in a building as conduction and convection. For more information on radiant barrier facings click here.

Commercial Buildings

It is said that close to 90% of all new commercial construction is a steel building system. The ease of construction makes a new steel building system more attractive to builders and owners alike. From carwashes to skyscrapers steel has, and will continue to lead the way. Steel buildings are great for workshops or manufacturing facilities, classrooms or church buildings, metal buildings are fast replacing less adaptable building systems. Today, more than ever our world is growing faster and more competitive. Architects and professional building designers are becoming more aware of the benefits of steel from a construction and economical standpoint. As new steel building systems are introduced, we see the bottom line improving on construction projects of all kinds. The ease of construction and versatility makes a steel building attractive for a variety of uses.

Insulating Against Radiant Heat

Traditional forms of mass insulation, like fiberglass, are effective in preventing heat transfer by conduction and convection, but they less effect on radiant heat. Between 80 and 90% of the radiant heat striking fiberglass will pass through or be "emitted". Radiant transfer typically has as much impact on the temperature in a building as conduction and convection. For more information on radiant barrier facings click here.

Heat Transfer

Effectively controlling temperature in a steel building requires insulation to be present along exterior walls and roof. When a temperature differential is present in an enclosed steel building, heat will work from warmer areas to colder areas until the temperature in the building has stabilized. At the point of thermal stabilization, the cooler (and heavier) air will be present at lower elevations and warmer air will be present at the roofline. The function of insulation is to help stabilize air temperature at more desirable levels. When it is hot outside, preventing heat from transferring into the building is the goal, and of course in the winter we want heat to remain inside.

Heat transfer occurs in three ways:

Conduction : Occurs in a solid or liquid when heat from one object is transferred by touch to another object. An example of this occurs when a pot on a stove will heat up by conductive heat transfer from an electric coil.

Convection : Occurs with the physical movement of air. There are two types of convectional heat movement. The first is natural, where hot air rises displacing the cold air and moving it down. The second type is forced or mechanical convection. This occurs when an object, like a fan, physically moves or "forces" the air to move.

Radiation : Occurs when an object is warmer or hotter than the air around it. For example, the sun, which is hotter than everything around it, radiates heat waves that travel through the air and is either absorbed by or reflected by the surface it comes in contact with.

Condensation Control

The condensation process occurs when warmer moist air comes in contact with cold surfaces such as framing members, windows and other thermally conductive accessories, or the colder region within the insulation itself (if moisture has penetrated the vapor retarder). Warm air, having the ability to contain more moisture than cold air, loses that ability when it comes in contact with cooler surfaces or regions. When this happens, excessive moisture in the air is released in the form of condensation. If this moisture collects in the insulation, the insulating value is decreased.

In dealing with condensation, air may be considered to be a mixture of two gases-dry air and water vapor. One thousand cubic feet of air at 75°F can hold up to 1.4 pints of water. At 45°F, it can hold only 0.5 pints.

Relative Humidity is a percentage measurement of the amount of water vapor present in the air in relation to the amount it is capable of holding at that temperature. Therefore, 50% Relative Humidity would mean that the air is carrying only one-half of the total amount of moisture that it could be holding at that particular temperature. Cold outside air is usually much drier than warm inside air. Therefore, you can lower the Relative Humidity by bringing in outside air to mix with and dilute the moist inside air. At 100% Relative Humidity, the air is "saturated."

The temperature at which the air is saturated and can no longer hold additional moisture is called the dew point temperature. Whenever air temperature drops below its dew point, excess moisture will be released in the form of condensation. Condensation problems are most likely to occur in climates where temperatures frequently dip to 35°F or colder over an extended period of time.