Author Jim Hingst, a 42-year veteran in the graphic arts field, recently posted a blog (Hingst’s Sign Post) containing an excerpt from an article he wrote several years ago for Sign Builder Illustrated detailing strategies for how best to protect vinyl banners from strong winds. As printers broaden their production of flexible media applications using superwide printers like Fujifilm’s new Acuity LED 3200R press, these tips could come in handy at installation time to ensure your display and exhibition graphics resist what Mother Nature can deliver!
Hingst reports a 75 mile-per-hour wind can generate nearly 15 lbs. per square foot of wind pressure at ground level and 21 lbs per square foot of pressure for banners mounted 15 feet above the ground. For a 4′ x 8′ banner, that’s equal to 460 lbs of wind load at ground level and 671 lbs hanging!
“These tremendous wind loads not only can tear apart banner material, but can also bend poles used to suspend banners.”
— Jim Hingst, Hingst’s Sign Post Blog, October, 2016.
Strategies suggested in the article include:
The usage of wind slits or wind pockets remains controversial. While some sign experts believe any banner larger than 30 square feet need them, others believe the slits actually weaken the banner. Hingst suggests being sure the vinyl banner materials being used are warrantied by the manufacturer before using this as an option.
If using a rope to install a banner, interweaving the rope from one grommet to others will help distribute the wind load over a greater area. Also ensuring tension on the ropes keeps the banner from flapping in the wind, a major cause of ripping.
Bungee cords are even better than ropes, providing extra stretching and giving when stressed by high winds.
When installing a banner against a solid surface like the wall of a building, pulling the banner tight prevents wind from getting behind the banner. Screws with washers installed in grommets spaced 24″ apart are recommended.
The use of steel cables are recommended for banners stretched across a street. The usage of heavyweight banner material (19 or 22 ounce) and 1/4″ aircraft cables secured to two poles on opposite sides of the street should suffice. If connecting the banner directly to a building, some sign makers deploy a backplate on the interior face of the wall which disperses the load over a larger surface area. For additional information regarding this type of installation, see the complete blog post.
Employing techniques like these can protect your quality display- and exhibition-sized graphics from gale force winds ensuring your clients get their message across in even the most challenging of out-of-home installations.