April 13, 2017

How Airflow Affects Condensation Control Efforts

Spring and fall bring great weather, but they also bring a problem all too familiar to facility managers: condensation. It’s more than an annoyance – it creates dangerous conditions and ruins products, costing businesses billions of dollars each year.

As a direct-sales manufacturer, Big Ass Fans worked directly with customers to understand the problem, and members of the company’s staff of degreed engineers visited numerous facilities in researching and developing Dewtect, a one-of-a-kind, completely automated condensation solution.

There are several ways airflow can help prevent or reduce condensation – and there are ways airflow can make the problem worse, which is why a control system capable of monitoring and predicting the possibility of condensation is needed. To understand how airflow mitigates condensation, you must learn how and why condensation forms.

How Condensation Occurs

Condensation forms when warm, moisture-laden air contacts a colder surface – think of a cold can of soda “sweating” on a hot summer day. That occurs because air cools next to the can, and cooler air holds less moisture. Water is deposited on the cold surface when the air cools to the point it can no longer hold moisture – commonly known as the dew point.

The same thing happens with a concrete floor or a giant coil of sheet metal or cardboard boxes. But unlike a soda can, wet floors and products can be costly.

Spring is most problematic because large, dense objects are slow to react to air temperature changes. A roll of sheet metal might hold its winter temperature for days or weeks after the weather warms up. And it can take a month or more of warm weather for the core temperature of a concrete slab to rise above the dew point.

In fall, it’s common for the dew point to surpass the surface temperature of floors, products and equipment. When warmer air moves in during the day, with it comes a rise in dew point and humidity, causing a slick layer of condensation to form over colder objects. And in fall and winter, it’s common for condensation to form on product that has been moved from a cold truck into a heated warehouse.

Wet floors cause people to slip and fall, and prevent forklifts from slowing down. Slip-and-fall accidents cost $70 billion in workers’ compensation claims and associated medical costs every year, at an average of $20,000 in claims per accident.[1] Condensation also causes rust, mold and mildew, which costs businesses billions. Rust alone costs the production and manufacturing sectors $17.6 billion each year, and can be damaging to both products, facilities and equipment.[2]

How airflow affects condensation

How Airflow Helps

There are numerous factors that cause condensation, including weather patterns, heat, humidity and dew point. There are numerous ways to combat it, too, such as the use of dehumidifiers, air conditioners and undertaking massive, costly projects to seal and insulate facilities. However, one of the most cost-effective ways of combating condensation involves the use of energy-efficient equipment many facilities already own: fans. Airflow from overhead fans reduces condensation in several ways, including:

Why Fans Alone Aren’t Enough

Because so many factors are at work, predicting condensation is nearly impossible for humans. In spring and fall, it would be a full-time job to constantly monitor indoor and outdoor temperature and humidity levels, the surface temperature of the object at risk for condensation, and approaching weather patterns. Because of this, many facility managers simply let their fans run constantly during condensation season.

But this can make condensation worse. Say a facility has been using fans to increase the surface temperature of a concrete slab. The employees turn out the lights and go home at shift’s end, and an unexpected cold front moves in at night. Just as airflow can warm a surface up, it can also cool it down quickly when the air being circulated is cooler than the surface. By leaving the fans running all night, the employees inadvertently cooled the surface down and put the facility in danger of a condensation event when the temperature heats up the next day.

Similarly, it seems obvious that ventilation systems should run all the time in order to eject moist air from a building. However, when a front of warm, moist air moves in, the best course of action for condensation prevention is to seal the building as best as possible. Replacing dry air in a building with humid air from outside, can potentially heighten the risk of a condensation event.

Take Human Error Out Of The Equation

Dewtect by Big Ass Fans links air movement with state-of-the-art sensors, HVAC and ventilation equipment to keep products and floors above the dew point. The control system automatically monitors ambient air temperature, surface temperature, humidity and trending dew point, and it prevents condensation using airflow from high-volume, low-speed Big Ass Fans.

With smart building operation on the minds of most facility managers, systems like Dewtect are the future of cost-effective condensation control.

[1] 2013 EHS Today “The High Cost of Slips, Trips and Falls.”
[2] 2002 NACE International and FHWA, “Corrosion Costs and Preventative Strategies in the United States.”

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