By Henry Burke
Insulated metal panels, or IMPs, have a wide range of uses for projects of all kinds. The concept itself is pretty straightforward: An IMP is a wall panel consisting of an exterior metal skin and interior metal skin sandwiching a layer of insulation.
IMPs can deliver a high level of energy efficiency without sacrificing aesthetics or budget. They can achieve the four critical barriers desired in a building envelope — air, thermal, vapor, and water — in one product.
While there are myriad subtle variations, IMPs are broken into two major groups: commercial/industrial and architectural. The two applications have very different needs. A commercial/industrial IMP is designed to provide high insulating value to warehouses and other industrial or light commercial construction projects. Architectural IMPs deliver a higher level of aesthetic quality; oftentimes, more is expected from the exterior skin.
”Commercial/industrial IMPs are designed to provide functionality first,“ explains Greg Lusty, director, Product Management and R&D at CENTRIA. ”Architectural IMPs are engineered to provide both form and function.“
At first, IMPs were used mainly in commercial/industrial applications.
”Insulated metal panels came out around 1970,“ recalls Keith Boyer, director, Design and Development at CENTRIA. ”The panels were vertical and they were fixed in module. I think we had two modules of 24 and 30 inches. And the metal skins were light in gauge.“
IMPs began to evolve from commercial/industrial to architectural applications as architects became interested in the technology and began to ask more from it. ”In the 1980s, we saw architects wanting to use vertical panels in a horizontal application,“ Boyer recalls. ”That led to a couple of things. If you were to take a vertical panel and turn it horizontally and erect it from the bottom up, the design of the joints from most manufacturers would not work. And with that bottom-up assembly, there would be a downward gutter on the face side that would entrap water. We had to design custom joinery that was meant to be used horizontally.“
In 1981, the Formawall® 1000 H panel was developed to meet the need for horizontal use of IMPs. ”There was a drain shelf horizontally that would allow water to freely drain out of the joint, and not accumulate and be trapped in the joint,“ Boyer explains. ”We wanted to give the panels an opportunity to perform and not be subjected to material degradation from long-term water contact.“
The design community soon realized IMPs could be useful in high-end projects, especially if the panels could meet increasingly varied aesthetic demands. Manufacturers like CENTRIA needed to continue to up their game.
”As time went on, more requests were put on the product to be used architecturally,“ Boyer says. ”Designers wanted a module they could vary. So we were able to adjust the module, anywhere from 10 to 40 inches in width, and the joinery was such that you could create a reveal — a recess at the joint — that would be readable. To go along with that, the product offered some shop fabrication, such as shop-bent corners. Another key architectural feature was the end treatment of the panel, where the face metal was bent inward by about 1 inch. On industrial panels, the ends are typically sawn and capped with trim.“
Curved panels were also developed along the way, allowing designers the flexibility of rounded corners and transitions. With clients demanding increased energy efficiency in their buildings, architects wanted to find ways to use IMPs while still achieving their aesthetic intent.
The concept of variable reveals also serves as a key design element in the architectural IMP industry. This aesthetic option is not available in the majority of commercial/industrial IMPs on the market.
One of the biggest leaps the product line took during its journey from industrial to architectural was in the flatness of the exterior surface skin of the panels. The thin-gauge metal skins used on the traditional industrial IMPs had a difficult time achieving the smooth look often required on high-end projects.
”Architects want to have a smooth skin, like the surface of an aluminum composite material (ACM) product,“ Boyer says. ”They don‘t like embossing and want to see a smooth, flat surface. We can do that, though it does increase the cost of the product.“
Part of achieving this smoother look comes from using a thicker metal on the skin of the panel. ”An industrial IMP skin is 26 gauge, or 0.018 inches, while a standard architectural IMP has a 22 gauge face, which is 0.030 inches,“ Boyer explains. ”So it is a considerably heavier face skin. We also have the ability to go to 20 gauge, which is 0.036 inches.“
Another challenge in accomplishing that flat, smooth appearance is in limiting the lengths of the panels. The more surface area on a panel, the greater the chance of oil canning or flatness variations. ”Embossing would hide some of that, but with a smooth surface, you can pick up these kinds of defects easily,“ Boyer says. ”Typically on a non-embossed flat architectural panel, the length restriction would be 16 feet.“
While both product types have grown and changed over the years, and developments on one type often get applied to the other, the primary difference today is that architectural IMPs add more expense via shop fabrication options and heavier material in order to achieve a more high-end aesthetic. ”An architectural panel weighs approximately 3 pounds per square foot, while commercial/industrial IMPs are closer to 2 or 2 ½ pounds per square foot,“ Boyer says. Industrial IMPs, due to the nature of the types of projects they are used on, are designed for economy, efficiency, and speed of construction.
”The commercial/industrial products are something of a commodity, and the competition in that market is keen,“ Boyer says. ”For the most part, we try to keep the manufacturing as lean as possible. The other thing to keep in mind is that the industrial products will have cleaner runs and longer areas of flat wall area that will install fairly quickly, as compared to an architectural project. With those, there can be a lot of variations, bent products, recessed windows, and other elements that make the installation slower. Most likely, the installation speed of an architectural IMP wall, in square feet per day, would be 20 to 50 percent of an industrial project.“
IMPs of both kinds continue to evolve today, as engineers and designers find new applications and explore more elaborate designs. ”With IMPs, you get the performance, but you also get the aesthetic you‘re going after,“ Boyer says. ”We‘re always looking at new variations.“
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