Humidity in Metal Buildings: Ensuring Safe Structures that Serve Operations Well

Humidity in metal buildings can be a complicated issue, one with large — and lasting — repercussions. While humid conditions can be uncomfortable and unhealthy for the people who work inside of a structure, excess moisture can impact the well-being of a structure and its equipment, as well. A well-planned ventilation approach paired with adequate attention throughout the metal building’s lifespan can make all the difference.

Here, Metallic Products’ airflow pros cover what metal building contractors and owners should know. From answers to basic questions such as “What is humidity?” to its impacts and ways to avoid costly issues, we’re here to keep your metal buildings serving you well.

What is Humidity?

Before we delve into its impacts and considerations for metal buildings, let’s go back to basics. What is humidity? The term refers to the amount of water vapor in the air. It serves as a measure of how moist or dry the air is and can be broken down into three main types.

It’s important to pay attention to indoor humidity levels throughout the year — and right issues as quickly as possible.

• Relative Humidity (RH): A metric often referenced in weather forecasts, relative humidity is a measure of how much moisture is in the air compared to the maximum amount that air could hold at a specific temperature. It’s shown as a percentage. High relative humidity indicates more moisture, while lower percentages indicate drier air.
• Specific Humidity: The ratio of the mass of water vapor to the total mass of moist air. Although this measure is referred to less commonly in everyday life, specific humidity is useful for industrial processes where precise humidity control is necessary.
• Absolute Humidity: The total amount of water vapor within a volume of air, as measured in grams of water per cubic meter. Absolute humidity changes as temperature or pressure shifts and is not referenced as often as the measures mentioned above.

How Does Humidity Affect Buildings and Operations?

Humidity is unavoidable, but it should be kept at a healthy level within a metal building. What’s ideal will vary, however, based on factors such as geographic region and the type of work you do. Experts generally recommend keeping relative humidity at about 30% to 50% for steel structures. Let’s look at the effects off-balance humidity can have on your metal structures and work.

High Humidity and Your Metal Buildings

Managing humidity in metal buildings plays a key role in creating healthy, comfortable environments while extending a structure’s lifespan.

Elevated moisture levels inside your metal buildings can lead to a number of issues.

• Rust & Corrosion Formation: High relative humidity levels can lead to oxidation on metal surfaces. Over time, a building’s structural integrity can degrade, not just creating safety hazards, but lowering a structure’s lifespan.
• Water Damage: When warm, humid air comes in contact with cool surfaces on or inside of your metal buildings, it results in condensation. That condensation can result in damaged insulation, water stains that impact aesthetics and reduced performance of your costly electronics and machinery.
• Mold & Mildew Formation: Stagnant condensation inside a building has the potential to fuel the growth of mold and mildew — particularly in warm conditions. In addition to creating odors and stains, it can lead to health concerns for those who frequent the building.
• Operational & Production Issues: Elevated humidity can impact processes such as painting, assembly and welding, introducing production delays or lowering the quality of the finished product.
• Issues with Climate Control & Energy Costs: High humidity levels often require HVAC systems and ventilation accessories to work harder, resulting in higher bills — and the potential for increased repair and replacement needs.

Low Humidity and Your Steel Buildings

Although discussion often centers around elevated moisture levels, low humidity can also impact steel buildings in negative ways.

• Static Electricity Buildup: Dry air elevates the risk of static electricity, which can be hazardous for structures which house electronic components, flammable materials or sensitive equipment.
• Reduced Process Efficiency: Extremely low humidity has the potential to result in equipment malfunctions or impact quality control. This is especially true for processes that hinge on healthy moisture levels, such as chemical applications, painting processes and material storage.
• Cracking & Warping of Non-Metal Building Components: Wood, rubber and certain plastics are especially vulnerable to low humidity, often cracking, shrinking or drying out when levels fall below what is ideal. When this happens to components such as window insulation or door seals, it leaves buildings vulnerable to air or moisture intrusion — and pests.

Watch Metallic Products VP Samuel Gray explain how ventilation accessories and insulation go hand in hand to keep condensation under control.

How to Control Humidity in Your Metal Building

Keeping moisture at an ideal level isn’t always cut and dried, but it is possible when gone about the right way. Here are a few tips from our ventilation pros regarding how to control humidity in your metal building.

• Incorporate Ventilation Accessories that Serve Your Unique Structure: It isn’t enough to have ventilation accessories in place. It’s important to have the right ones — incorporated the right way. Ridge vents whose throat sizes can’t provide the amount of air movement needed for operational output, for instance, won’t do much good. Likewise, accessories in the wrong place, such as large ceiling fans mounted below ridge vents, or louvers that don’t feed air where needed, can cancel ventilation efforts out. We recommend working closely with your accessory provider from a project’s start to position your build for success.
• Ensure Your Accessories & Insulation Work Together: Quality insulation inside a metal building helps keep temperature fluctuations to a minimum — and reduces the risk of unwanted condensation. Even so, it’s just part of the puzzle. That insulation needs to be able to breathe, and ventilation accessories such as louvers and ridge vents play a key role in allowing that to happen. Without airflow, moisture buildup becomes trapped, leaving your building vulnerable to the aforementioned concerns.
• Monitor Moisture Throughout the Year: Humidity in metal buildings is closely linked to moisture and temperature levels both inside the structure itself — and in the outdoor vicinity. Because those factors will ebb and flow as seasons change and manufacturing or production levels ramp up, your methods of control will need to follow suit. You’ll likely need to increase airflow during hot summer months, or after heavy rainfall. On the flip side, during days when on-site production is at a minimum, your space might not require as much ventilation assistance as usual. Consider using a hygrometer to gauge conditions.

Maintaining a healthy level of humidity in metal buildings isn’t difficult, but it does take some forethought. If you have questions about your building’s ventilation needs, or if you’re interested in learning how Metallic Products’ made-in-America accessories can help, feel free to reach out. We look forward to hearing from you and helping to move your projects forward.