"Made in America" has taken on new meaning over the past two years as the world has grappled with a massive supply chain issue.

For the building industry this has translated into delayed projects as contractors await precious supplies from far-flung manufacturers that are stuck on cargo ships anchored off congested ports.

When it comes to insulated metal panels (IMPs), however, builders do not have to look to China or other parts of the world as companies like Texas-based Green Span Profiles, turn out the versatile wall and roof panels daily for the low-temp/cold storage market as well as architectural and commercial/industrial construction projects.

State-of-the-Art Equipment Manufactures IMPs

Green Span Profiles utilizes state-of-the-art equipment at its 70,000-square foot manufacturing facility built in 2011 in Waller, Tex., just outside of Houston, to produce a diverse line of eight different IMP profiles:

• CleanLine: Partition Wall, Liner Wall, Ceiling
• Impression: Exterior Wall
• MaxLine: Partition Wall, Liner Wall, Tee Supported Ceiling
• MesaLine, MesaLine HSE: Exterior Wall, Partition Wall, Liner Wall, Ceiling
• ShadowLine: Exterior Wall
• WaveLine: Exterior Wall
• INSULROCK: Fire Rated Panel
• RidgeLine: Exterior Standing-Seam Roof

The IMPs are built by a continuously poured-in-place process binding interior and exterior corrosion-resistant steel facings to a polyisocyanurate insulating foam core.

Quality control is paramount, and the IMPs are rigorously tested by Factory Mutual, Underwriters Laboratories and Miami-Dade County.

Polyisocyanurate Foam Key to IMP Manufacturing

IMPs are lightweight composite exterior wall and roof panels with metal skins and an insulating foam.

“Ideal for both retrofits and new construction as an all-in-one air and water barrier with continuous insulation, roof and wall insulated metal panels deliver a plethora of performance, erection, durability, and aesthetic benefits,” says the Metal Construction Association (MCA) Education Continuing Education Center.

IMPs register the highest insulating value of any cladding material on the market (6.2 to 6.7 per inch R-value vs. 4.5 per inch for batt insulation), thanks to the insulating foam core sandwiched inside the sheets of coated metal that prevents any metal conductance from exterior to interior skin.

IMPs one-shot building enclosure installation eliminates the need of multiple trades required with conventional stud construction.

“Separate materials installed individually have greater potential for failure points,” Tim Keil, RA, associate principal with the Phoenix-based architectural and environmental design firm Studio Ma, told the MCA. “As a single system, IMPs can improve weather and airtightness, which are key for high-performance buildings.”

In the manufacturing of IMPs, the ship-in-the-bottle moment is the sophisticated step where the polyisocyanurate foam is injected between the two sheets of coated steel or aluminum.

To pull off this magic trick, manufacturers like Green Span Profiles, must inject the elements that comprise the polyisocyanurate foam in liquid or froth form between the metal.

“Responding to a chemical reaction, the foam then expands to fill out the cavity, ultimately producing a panel capable of delivering a stable thermal value and resisting moisture and insect/rodent infiltration,” said the MCA.

Example of Step-by-Step Manufacturing

The Polyisocyanurate Insulation Manufacturers Association (PIMA) gives an example of how the manufacturing process of a polyisocyanurate insulation material might occur, step-by-step:

Step 1: Raw Material Unloading and Storage: Raw materials are delivered to the manufacturing plant via bulk shipment methods like rail cars or large totes. After unloading, certain materials are transferred and stored in large on-site tanks or totes.

Step 2: Facer Unwind: Rolls of facer material are loaded on the front end of the lamination line. Two rolls of material are unwound and fed toward the laminator. The material will become the top and bottom of the finished product.

Step 3: Compounding: Raw materials are compounded and heated to form the polyol or B-side component of the product formulation. The isocyanate or A-side of the product formulation is heated and transferred through a separate line.

Step 4: Mixing Head and Pour Table: The A-side and B-side components are mixed with the blowing agent at the mixing head. At the pour table, the mixture is applied through the mixing head applicator and laid onto one layer of the facer material. The chemical reaction begins at this point in the process and the second layer of the facer material is brought into contact with the foam mixture as it enters the laminator.

Step 5: Laminator: The chemical reaction transforms the liquid mixture to the rigid foam core as the product moves through the laminator. The laminator is used to control the thickness of the finished product as well as other characteristics like cell formation, curing, and facer adhesion. The laminator can also be adjusted to form any tapered characteristics for finished panels.

Step 6: Trim and Cutting: The product is manufactured in a continuous process and must be trimmed and cut after exiting the laminator. A cross-cut saw and gang saw are used to cut the material down to finished lengths.

Step 7: Robot Stacker: A conveyor system moves the panels through the trimming and cutting process to the robot stacker. An initial quality check is performed as the panels are stacked in bundles.

Step 8: Packaging: The stacked bundles are transferred to a hooding machine where each bundle is individually wrapped with a plastic film. The factory packaging secures the product for warehouse storage and transport.

Step 9: Foot Station and Warehousing: The product identification labels are applied to each bundle. A forklift transfers the bundles from the end of the line to warehouse storage. Panels complete the curing process while stored in the warehouse.

Step 10: Quality Assurance and Control: Product samples are selected and subjected to various quality assurance and quality control (QA/QC) testing. The QA/QC is performed against applicable standards and internal controls for physical properties like initial R-value, compressive strength, and dimensional stability.

Step 11: Loading and Shipping: After QA/QC testing and storage in the warehouse, bundles are transferred to the loading dock. Bundles are loaded onto flatbed trucks and secured for transport to job sites or distribution locations.