· Allowing airflow between rooms of steel buildings is important. Interior doors should always be open to allow for whole-building ventilation. However, for rooms that require privacy, installing louvers or transoms is one way of providing ventilation.

· For steel buildings with attics, ventilating the attic space creates a major reduction in heat transfer to air-conditioned rooms below. It has been found that a well ventilated attic is 30°F cooler than unventilated ones.

· Consider the use of motorized fans like ceiling and whole-building fans. This strategy can provide up to 9°F temperature drop at one tenth of the energy consumption of mechanical air-conditioning systems.

· Determine which of the two methods work well to achieve natural ventilation – closed-building approach or open-building approach. For hot and dry climates where there is a significant difference between day and night temperatures, a closed-building approach is ideal. A large building is open at night to allow cooler air to come in and closed during the day to keep out the hot daytime air.

For steel buildings in war and humid areas where there is not much difference between day and night temperatures, an open-building approach is best. An open-building approach means that daytime cross ventilation is encouraged to maintain comfortable indoor temperatures.

· Opt for open staircases because they provide stack effect ventilation for steel buildings.

Source: http://www.wbdg.org/resources/naturalventilation.php#

· To maximize wind-induced ventilation, sit the ridge of the steel building perpendicular to the summer winds. To approximate wind directions, refer to data contained in “wind rose” diagrams available at the National Oceanographic and Atmospheric Administration (NOAA).

Steel buildings are best sited where summer wind obstructions are minimal. A windbreak of evergreen trees planted around metal structures, are useful in lessening cold winter winds that typically come from the north. If designed properly, windbreaks can reduce the cost of heating and cooling, bringing down energy consumption.

· Natural ventilation is applicable to steel buildings that are narrow. Distributing fresh air to all portions of a wide steel building is very difficult. Steel buildings that have a maximum width of 45 feet can be naturally ventilated.

· Each room should have two openings, one for supply and one for exhaust. The exhaust should be preferably located high above the inlet to maximize the movement of air into and out of the building. Windows should be placed across the room so as to balance each other to maximize airflow within the room. This design also minimizes obstructions to airflow within the room.

· Ensure that all window openings are operable by the building occupants.

· Make provision for ridge vents. A ridge vent is an opening installed at the peak of a sloped roof that offers a good outlet for both buoyancy and wind-induced ventilation. It is important that ridge vents are free of obstructions to allow air to flow freely out of steel buildings.

Source: http://www.wbdg.org/resources/naturalventilation.php#

Natural ventilation would benefit the following types of steel buildings:

· Bus stations, picnic shelters, and other steel buildings where stringent space conditioning (space heating + space cooling) is not expected
· Barracks and other single- and multi-family housing projects
· Small, free standing steel buildings in warm and temperate climates
· Warehouses, maintenance pools, and other high-bay facilities in warm climates

The online encyclopedia defines natural ventilation as the process of supplying and removing air through an indoor space by natural means. Counting on natural forces such as wind and buoyancy, natural ventilation systems rely on variations of pressure to deliver fresh air through buildings. For steel buildings to have efficient natural ventilation, both types should be implemented.

Wind blows air through the openings in the wall on the windward side of steel buildings, and suck air out of openings on the leeward side and the roof. Temperature variations between warm air inside and cool air outside causes the air in steel buildings to rise and exit at the ceiling or ridge, and enter via lower openings in the wall.

In the same fashion, buoyancy caused by a difference in indoor-to-outdoor air density resulting from temperature and moisture differences allows a pressurized column of dense, cooled air to come in, and lighter, warmer, humid air to come out near the top of steel buildings.

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Source: http://www.wbdg.org/resources/naturalventilation.php#

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 for steel buildings are further categorized as through-fastened (overlapping panels) or standing seam (interlocking panels). Through-fastened metal roofing uses screws to directly attach it to purlins or the metal roof deck.  Steel shingle or standing seam roof uses hidden clips or fasteners to minimize the number of penetration through the steel panels. The concealed clips also permit expansion and contraction.

Structural metal roofing for steel buildings can be classified as low slope and steep slope. Roof slope or roof pitch determines the steepness of the angle of the roof. A low roof slope ranges from ¼:12 to 3:12. Any angle above 3:12 is considered steep slope.

Whether standing seam or through-fastened, low slope structural metal roofing system is, characterized by panels that run vertically on the roof surface. Typically, for roof slopes less than 3:12, special machines that crimp the panel seams together are used to ensure weather-tightness.

For steep slope structural metal roofing, vertical and horizontal profiles are available. The vertical panels consist of standing seam systems that are attached to underlying purlins with hidden clips or fastening flanges. Also available are various corrugated or tile facsimile metal roofs that overlap and are attached directly through the metal roofing panels. The interlocking or overlapping panels ensure weather-tightness.

Instead of transmitting loads through purlins, non-structural metal roofing systems for steel buildings transfer loads to the metal roof deck beneath them. The choices of styles for non-structural systems include vertical standing seam, corrugated, tile profiles, and a variety of horizontal panels.

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

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

Cool roofs are mostly used in commercial and industrial steel buildings application. What are cool roofs? A cool roof is a roof consisting of materials that has the ability to reflect the visible, infrared, and ultraviolet wavelengths of the sun, reducing heat transfer to the steel building. At the same time, it has the ability to radiate absorbed solar energy. These characteristics are better known as solar reflectance and thermal emittance. Most cool roofs for steel buildings are white or light-colored.

It has been proven that cool roofs can reduce the roof surface temperature by up to 100 degrees Fahrenheit, thus lessening the heat transferred into the steel building below. This translates to reduce energy costs, maintain comfortable interiors, lessen maintenance costs, enhance roof’s durability, and reduce urban heat island effect.

Some benefits of cool roofs for steel buildings are:

· Reduce steel building heat-gain
· Create savings by reducing the need for summertime air conditioning
· Increase the roof’s life expectancy as well as the steel building’s cooling equipment
· Increase the thermal efficiency of the roof insulation
· Reduce the demand for electricity by as much as 10% on hot summer days
· Reduce air pollution and greenhouse emissions resulting from the use of cooling equipments
· Provide energy savings even on sunny days when the weather is not necessarily hot

For steel buildings, metal roofing products in dark colors, even black, that are coated with “cool roof” pigments may not be as reflective as those in whites or light colors, but they can still provide energy savings over other paints.

Ridge vents can be singularly installed or seamed together for longer applications. Ridge vents come with accessories such as bird screens, rain caps, dampers, connector bars, and gutter splices. The last three are essential when installing multiple units in a continuous run.

Typically, a ridge vent is opened by a pull chain, but different opening mechanisms are also available at an additional cost. Ridge vents are great for low-pitched roofs as well as cathedral ceilings. To determine the size of ridge vent a steel building needs, it has been demonstrated that a 10-foot ridge vent can properly ventilate a 2,400 square foot steel building.

Circular vents are typically 20 inches in diameter. Each circular vent comes with a bird screen and a spring-loaded butterfly damper that locks open until released.

For small steel buildings, installing louvers is the best option. However, they are typically used in tandem with other ventilation systems such as ridge vents to ensure proper air exchange. They come in these sizes: 3 ft. x 3 ft., 3 ft x 4 ft., 3 ft. x 4 ft., and 4 ft. x 4 ft. Louvers can be installed in any unobstructed area of a steel building’s walls.

Crosswise ventilation is necessary for some steel buildings. This can be achieved by placing louvers along the base of the steel building to increase the efficiency of the ridge vent on the roof. For steel buildings that are to be inhabited by people or livestock, suppliers can help owners calculate the sufficient amount of ventilation needed by using tried and tested formulas.

Aside from preventing condensation, ventilation is also necessary for heat reduction, exhaust of noxious fumes, or simply pull in some fresh outside air for steel buildings.

This means that to prevent condensation from occurring, maintaining a relative inside humidity of less than 60% is important. The best solution to lowering the indoor relative humidity of steel buildings is to bring in outside air to mix with the inside air. This is achieved through proper ventilation.

Ventilation, or air exchanges, lets outside air into steel buildings and at the same time lets warm moist inside air escape. There are a number of factors that contribute to an extremely high moisture content inside steel buildings, making ventilation crucial. One concrete example is a barn used as shelter for livestock, such as horses.

A single horse excretes approximately 2 gallons of moisture, in the form of sweat, into the air everyday. In addition, the urine of the same horse also expels moisture into the air. Without a proper ventilation system in place, moisture will collect on the roof of the steel building and create a moist environment that can lead to respiratory ailments and fungal growth.

A steel building used as a barn, should be designed to have enough ventilation to ensure six to eight air exchanges per hour. This is achieved through ventilation systems such as ridge vents, circular vents, and louvers. These may be used alone or in combination.

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The following are the typical dimensions of steel buildings used as backyard storage and garden sheds:

Width: The width ranges from 14 feet up to 20 feet but can be larger depending on needs.

Length: The length of the steel building really depends on the particular needs of the owner. The arched type of steel buildings allow for structures of any length.

The following benefits are realized when prefabricated steel buildings are used:

Custom design - Prefabricated steel buildings are custom-designed based on the owners’ specific needs and budget. No matter what size is ordered, manufacturers will engineer and manufacture the steel buildings to suit your purpose.

Affordable - More often than not, suppliers of prefabricated steel buildings also own the factories that manufacture the metal structures. Therefore, they can offer steel building kits at factory prices.

Clear span interiors- Structures that are meant for storage should have maximum usable interior space. This is one of the unique benefits offered by prefabricated steel buildings. Their truss-less design ensures that you have enough room for racking, shelving, and parking large vehicles such backhoes, tractors, and recreational vehicles.

50 years warranty - Reputable prefabricated steel building manufacturers are so confident in the durability and strength of these metal structures that they provide up to 50 years of structural warranty to their products.

Backyard storage and garden sheds are extensions of your house and they should be in tune with its style. This is not a problem for steel buildings. Modern prefabricated steel buildings can be accessorized with different architectural finishes, such as brick or stucco, and a wide variety of paint options, to make them look like conventional structures and blend in with your house and the rest of the neighborhood.