blog
Healthy, comfortable indoor environments are crucial for any metal building, and proper ventilation is a key factor. Adequate airflow aided by concepts such as the chimney effect and cross ventilation can help regulate temperatures, keep moisture buildup to a minimum and make the air safer for those inside a structure. On top of that, it can help extend the structure’s lifespan by warding off mold, mildew and corrosion.
A building’s ideal approach to airflow will vary based on factors such as its size, use, architecture and output, but passive approaches such as those mentioned above are popular due to their efficient, cost-effective nature. At Metallic Products, we believe the more a person knows about the concepts and components that aid healthy ventilation, the better able they are to look out for their people and property. Here, we offer a deep dive into passive airflow — its scientific principles and the accessories that make it possible.
Passive ventilation approaches such as those that use the chimney effect are eco-friendly and cost-effective.
Before diving into the ways metal building owners foster effective passive ventilation, it’s important to understand what that concept means. So, what is passive ventilation? It’s a natural means of encouraging healthy airflow achieved without mechanical fans or electrical systems.
A passive ventilation system relies on natural wind and scientific principles such as temperature differentials and air pressure to move air through a space. Because it accomplishes its work without electricity, this approach is often viewed as an eco-friendly option that’s easier on the budget — while remaining effective.
It’s important to note that, although passive ventilation is effective, it’s often only part of the solution for a steel building’s airflow needs. Industrial operations frequently take a hybrid approach to ventilation, marrying passive and mechanical solutions in ways that keep air moving. Let’s take a look at some of the most common methods of passive ventilation.
The chimney effect is a ventilation concept that centers on the idea that warm, less dense air rises while heavier cool air remains lower to the ground. It’s also known as the stack effect, due to the idea that air of varying densities will sit on top of one another.
Metal building owners and contractors can optimize the chimney effect by installing intake vents or louvers low on a structure and situating ridge vents at the roof’s highest point. When installed correctly, this setup fosters a continuous system where cool, fresh air is ushered into the space while warm, stale air is exhausted. Although effective for a wide range of buildings, the chimney effect is ideal for tall structures or those with higher ceilings, as the more pronounced temperature differentials aid in air movement.
The wind effect, also known as cross ventilation, is the idea that you can cool a space by ushering fresh air in one side of a building — and warm air out another. This aptly named approach to airflow relies on wind power.
When wind approaches a structure, the building’s windward side experiences high pressure while its leeward side — or the side shielded from the wind — experiences low pressure. By placing louvers and intake vents on the side of the building experiencing the wind, and exhaust vents on the other side, a building owner or contractor can use pressure differences to their advantage. The wind effect is especially useful for buildings with open or semi-open designs that allow for unimpeded airflow.
Bernoulli’s principle ventilation is a passive approach to airflow that hinges on the speed and pressure of the air passing over a structure. As mathematician Daniel Bernoulli stated, as the speed of a fluid (which, in this case, includes air) increases, pressure decreases.
In the metal building world, ridge vents and louvers regularly contribute to Bernoulli’s principle ventilation. As air moves over these strategically placed openings, velocity increases while pressure drops. This combination draws warm, stale air out while ushering fresh air in through the intake vents. Windy environments lend themselves to Bernoulli’s principle ventilation.
The low profile ridge vent offers warm, stale air, fumes and smells an opportunity to escape.
There are a few key steel building ventilation accessories that regularly factor into passive approaches to airflow.
• Ridge Vents: Situated at the peak of a metal building’s roof, ridge vents give warm, stale air a place to escape.
• Wall Louvers: Located near a metal building’s lowest point, the wall louver helps to regulate environments by allowing fresh, cool air in.
• Gravity Vents: A blanket term for a range of products such as round vents and turbine vents, gravity vents encourage airflow and regulate temperatures, particularly in areas such as attics, lofts or warehouses.
Remember, it isn’t enough to simply incorporate these ventilation accessories into a steel building. They must be installed in the right places — and the accessories themselves must be suited to a structure’s unique needs. Buildings of various sizes, uses and output will have different airflow needs. You’ll want to make sure your gravity or ridge vent’s throat size is up to the task, for instance, and that your wall louver provides the amount of control your operations need over airflow. We recommend working closely with a trusted accessories provider to ensure you have the right tools for the job — and that they’re installed where they should be.
Passive ventilation can be a powerful and effective way to keep a metal building safe and healthy, but it takes careful planning to ensure optimum success. If you have questions about any of the above, or if you’re interested in incorporating passive ventilation approaches into your steel buildings, feel free to contact Metallic Products. Our ventilation pros love talking shop, and we’d be glad to help you find the right solution for your next project.
