Ridge vents are fixed vents installed on the roof to ensure proper air ventilation inside steel buildings. Made of metal and usually covered with shingles, ridge vents will appear inconspicuous on roofs. Their widths vary, from 10 feet to 12 feet, with 9 inches and 12 inches throats. However, ridge vents may be customized to accommodate roofs with wider beams.

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.

Sufficient ventilation is important to any building most especially to steel buildings, which are susceptible to condensation. As discussed in the previous post about insulation, condensation is the process where water vapor changes to liquid. The higher the relative humidity inside the steel building, the greater the water vapor content.

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.

(to be continued)