Banner Wind Vents

What is a banner "wind vent"? Does cutting holes help in reducing the wind load and prolong the life of a banner?

Here is a common thought concerning wind vents:

Wind Slits or Wind Vents - "Small openings are cut in the fabric in order to allow the wind to pass easily through the banner. A large banner without wind vents is really more of a sail. Without vents to reduce some of the wind load on a banner, the banner could rip."

These half circle vents are commonly cut into banners, generally at the request of the customer.  It is the common belief that wind vents are effective in reducing the wind load on banners. I am over 25 years in the industry, and I have yet to come across a single study where the effectiveness of wind vents has been demonstrated. The effectiveness is primarily in the visual effect of seeing the little flaps in a banner open up in the breeze. In reality only a very small percentage of the wind striking the banner passes through each vent. Any studies I have come across state that wind vents do not significantly reduce the wind load on a banner.

Let's think about this for a minute… If you have a 5' x 20' banner, the total surface area of that banner is 100 square feet. In order to reduce the wind load a mere 10%, You would need to effectively reduce the surface area by 1/10th or 10 square feet. That would require either (10) 1' x 1' vents or (20) 6" x 6" vents. Cutting this many vents makes the banner look a bit like a slice of "swiss cheese" and message less legible. Each individual vent also creates 2 new  "stress points" in the banner.  These stress points degrade the overall strength of that banner and can ultimately lead to premature banner failure, which can create a potentially more dangerous situation. Below is an example of a "well vented" and difficult to read banner.

We therefore do not recommend wind vents in banners.  We feel that there are better options available. such as high wind mesh or net banners.  Many cities will not put banners up unless they have wind slits and often include them in their design specs. When this happens, we will cut wind vents into the banner at the request of the customer. As they say, "The customer is always right".

We would be happy to discuss this issue with anyone who might have comments or questions.