Banner Grommet Strength
Why grommets are important
I recently was requested to quote on a large banner removal. The banner size is 12′ x 50′ on the side of a high rise, and the banner weighs roughly 150 pounds. This banner was located in Edmonton facing North, and for Edmonton most of the strong winds either come from the North or West.
After inspecting the above photos you can see there were multiple issues with the banner the big issue being the installation. The installation was wrong because they installed the banner over a sharp lip at the top, this created a short lifespan for the banner and ripped the top lip, rendering all the top bolts useless. The other issue we see is the bolting the banner to the building doesn’t allow for stretch and stretched the ink in some places and ripped the banner at the bottom bolt joints.
I feel like I can safely assume nobody wants to spend the money to print a banner this big to have the outcome look like the pictures above after a year.
Mesh Banner Testing
I have done some research and testing with grommets to see how much force will cause a banner to give out.
Mesh Banner No Edges
Mesh banner stretches at 50-60lbs of force and will create stretch marks within the ink.
Mesh Banner With 13oz Stitched Along The Edge
At 100lbs of force the grommets are giving out
at 250lbs of force the grommets start to give out.
How do we solve these issues
To prevent the grommets from pulling out or ripping, edging should be folded over webbing and stitched together. To prevent ink from stretching we would need to create or use a tensioning system that can absorb the force of 100km winds. To calculate the force visit https://www.hivismediainstallations.com/banner-wind-load/