Insulated metal panels
(IMPs) have been gaining popularity and visibility over the past decade, bringing a new level of innovation to metal buildings. IMPs, which have a layer of insulation between two metal panels, provide the most effective way to build a sustainable and energy-efficient building. Not only can they last longer than many conventional construction materials, they also offer the simplicity of one-step installation and can help building owners increase energy efficiency while cutting costs.
Eco-friendly and long lasting
Typical metal buildings are excellent in terms of longevity, but when IMPs are used for roofing and wall cladding or for interior partitions, they can enhance building performance even further. The panels are more durable (many varieties are guaranteed for 20 years) than traditional insulation, like fiberglass, because of the integrated metal skins. The exterior and interior metal panels protect the foam insulation against deterioration and, subsequently, increase the longevity of the building. To compare, fiberglass insulation has vinyl or comparable facing on the interior side, which can easily be damaged when exposed to the interior of a building.
IMPs can also add to the sustainability of a building. The steel faces of IMPs are made with roughly 30 percent recycled content and the foam is made of approximately 7 percent pre-consumer recycled content. Once installed, the panels further promote sustainability by reducing fossil fuel usage for the building owners by offering excellent thermal performance and air-infiltration resistance.
One-step installation process
Although there are actually four main components to each IMP
(exterior panel, interior panel, foam core and edge joint), they arrive at the job-site pre-manufactured and fully assembled. This, along with the fact that fewer panels are needed because standard panels are wider than standard single-skin panels (single sheet of metal with no insulation), decreases construction duration considerably. The factory-fabricated panels are attached directly to the supporting structure and as such, the multiple steps previously needed to construct an insulated wall and roof are eliminated.
Faster building completion means reduced construction and interim financing costs. To give an idea of how quickly these panels can go up, a skilled three-man crew would need approximately five to six minutes depending on lifting method to install each 24-foot-tall panel. For fiberglass insulation, expect an eight-minute-per-panel install or more, if weather is cooperative. A windy day can easily disrupt the installation process of fiberglass blanket insulation. Trying to keep the insulation in place against the single-skin metal panels can be quite difficult in high winds. Because IMPs are rigid and delivered already assembled, factoring in this possible delay is not necessary.
Effectiveness in insulation
On a very simple level, it is easy to see that R-values per inch of insulation are higher when using IMPs. As a general reference, in a thermal transmission test with a 75 F mean temperature, a 2-inch IMP has an R-value of 14.28, a 4-inch IMP has an R-value of 28.6, and a 6-inch IMP has an R-value of 42.9. Using the same test method, a 3.5-inch layer of fiberglass insulation will provide an R-value of 11, and a 6-inch layer will provide an R-value of 19. Moreover, fiberglass insulation has much less R-value when it is compressed, as is often the case in metal building construction.
Not only do IMPs have a higher R-value per cubic inch than fiberglass, they are also more effective due to their consistency throughout the building. IMPs have an advanced polyurethane core, which provides a consistent R-value for the entire building envelope that will last throughout the structure’s lifetime. When IMPs are installed and sealed properly, their insulation is encapsulated by metal trim that creates an impermeable membrane on all sides of the panel. With these panels, there is no compressed insulation or thermal bridge. The foam center stays constant in thickness, from base to eve and eve to roof, yielding the same R-value even over secondary steel framing.
Conversely, fiberglass’ R-value is more variable. It decreases when the insulation is compressed between the metal wall panel and horizontal members in the wall. For example, if a 6-inch layer of fiberglass was being used, its typical “R” of 19 could be reduced to 13 +/- after compression. The inconsistency in the thickness of the fiberglass, added to the need for manual labor to secure it to the frame, leaves a large margin of error, meaning the insulation likely won’t reach its potential of thermal resistance.
IMPs offer building owners some of the best savings and efficiency benefits that today’s metal construction industry can offer, but for those benefits to be fully realized, the products must be installed properly. Therefore, the knowledge of appropriate methods and procedures of installation is key for builders to see their return on investment. All installers are encouraged to seek necessary training from a reputable source to ensure the panels are handled safely and in accordance with the architect’s plan.
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Wes Young, product training and development manager at Houston-based NCI Building Systems, and Chip Moyer, product support manager at NCI Building Systems, have decades of collective industry experience and now work together to manage and host NCI’s many training seminars, including an insulated metal panel program, which is held eight times throughout the year in different areas of the country. For info on NCI, visit www.NCIGroup.com.