Insulated metal panels (IMPs) have become a popular material for modern commercial and industrial construction projects. One major driver of this growth is the rapid expansion in data center development. The surge in data center construction, driven by rising demand for cloud computing and artificial intelligence (AI), has helped fuel the demand trend. The global data center market is expected to grow from $418.2 billion in 2025 to $691.6 billion by the end of 2030, according to BCC Research.¹

In sectors such as data centers, distribution centers, and manufacturing facilities, the sooner the building is completed, the sooner it can start generating revenue, driving the need for building envelopes that can be installed quickly and reliably on schedule.

As demand for construction schedule compression increases, IMPs offer a seamless solution that combines water, air, vapor,  and thermal control layers into a single, easy-to-install assembly. By addressing envelope performance requirements, sustainability concerns, and financial considerations of employing IMPs, specifiers can understand their advantages in commercial construction and make informed decisions to successfully incorporate IMPs into design plans.

Overview of IMPs

IMPs are a prefabricated building material composed of two metal skins surrounding an insulating core. The metal skins are generally made of steel or aluminum and provide durability, unique aesthetics, and weather resistance, while the insulating core, most commonly a closed-cell foam material, contributes to durable thermal performance. The insulating core can be made from various materials such as polyisocyanurate (polyiso) foam or mineral wool, depending on the building envelope performance requirements.

IMPs offer several advantages over traditional wall systems, like tilt-up concrete or other multi-component wall systems, including faster installation times, reduced complexity, and fewer trades involved. Time-lapse installation comparisons indicate that IMP systems can be installed in roughly half the time required for traditional multi-component wall assemblies.²

As Joseph W. Lstiburek, PhD, P.Eng., of Building Science Corporation notes, “If you can’t keep the rain out, don’t waste your time on the air. If you can’t keep the air out, don’t waste your time on the vapor.”

IMPs inherently align with this approach by integrating air, water, vapor, and thermal control into a single assembly. By addressing these layers collectively, rather than relying on multiple, site-installed components, IMPs reduce the risk of discontinuities that can compromise envelope performance, particularly at transitions, penetrations, and interfaces between systems.

By integrating multiple functions into a single panel, IMPs reduce the complexity and cost of the building envelope while enhancing overall performance. Research shows that IMPs can lower overall installation costs by up to 25 percent in the U.S. compared to conventional tilt-up and precast concrete methods.³

Sustainability and resilience remain critical priorities across the built environment. Health Product Declarations (HPDs) and Environmental Product Declarations (EPDs) are rapidly becoming baseline requirements for the evaluation and specification of building products. The carbon impact of concrete construction is well documented, and the industry is actively pursuing strategies to reduce embodied carbon in these systems. IMPs offer a compelling alternative, with the potential to reduce a building’s overall carbon footprint by up to 28 percent compared to conventional concrete assemblies, particularly when paired with low-carbon slab solutions.⁴

Key performance characteristics of IMPs

Thermal performance

One of the most significant advantages of IMPs is their high thermal performance, which directly impacts building efficiency. The insulation core of an IMP typically provides a high R-value, a measure of thermal resistance. IMPs commonly achieve initial R-values of 7.2 per inch of thickness, and up to R–8 per inch for some newer proprietary foam formulations, when tested at 24 C (75 F) in accordance with ASTM C518, Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus. These values represent initial thermal resistance, as there is currently no codified industry standard in the United States for determining long-term thermal resistance (LTTR) for IMPs, and manufacturers typically report R-values based on ASTM C518 testing. This performance is significantly higher than that of traditional insulation materials such as fiberglass or mineral wool, which typically provide R-values of around 4 per inch of thickness.

This enhanced performance is largely attributable to the use of advanced low Global Warming Potential (GWP) blowing agents, such as hydrofluoroolefins (HFOs). These blowing agents are introduced during the manufacturing process to create the closed-cell structure of the foam, reducing thermal conductivity and improving long-term thermal stability.

These closed-cell materials, typically polyiso, provide higher thermal resistance and better moisture control than traditional batt insulation—pre-cut blankets made of fiberglass or mineral wool. This is due to the closed-cell foam’s ability to durably capture these low thermal conductivity blowing agents within the closed cell structure, while fiber-based batt insulations rely on trapped or entrained air, limiting the achievable R-value and leaving the assembly vulnerable to “wind washing”—the reduction of insulation values due to the movement of air through the batt.

Closed-cell foams retain their R-value over time significantly better than open-cell foams. And IMPs retain their R-value better than traditional board stock. Diffusion of blowing agents, moisture exposure, and thermal cycling all contribute to the thermal aging of insulation board stock and can be accelerated by improper installation. However, IMPs, closed and sealed systems, avoid many of these pitfalls, with long-term thermal drift often less than five percent, allowing some IMP manufacturers to offer 30-year thermal warranties on their systems.

Air and water leakage control

Air and water leakage are significant concerns for building envelopes. In multi-component wall designs, selection of the appropriate control layers, based on climate zone, code requirements, and hygrothermal analysis to ensure assembly compliance and long-term durability can be confusing and risky. Multiple vendors across multiple layers with differing performance properties within a single assembly means that expensive testing is often replaced by engineering judgment. Even with proper assembly design, specification, and detailing, issues with trade coordination and installation integration can result in energy losses, water intrusion, and structural damage.

IMPs offer robust solutions to these issues by integrating air and water control features directly into the single-component panel system installed by one contractor. IMPs are tested as complete barrier systems, simplifying code compliance compared to traditional multi-component wall systems.

IMPs are subjected to rigorous air leakage tests, such as ASTM E283, Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Skylights, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen, and water leakage tests, including ASTM E331, Standard Test Method for Water Penetration of Exterior Windows, Skylights, Doors, and Curtain Walls by Uniform Static Air Pressure Difference, and AAMA 501.1, Water Penetration of Windows, Curtain Walls and Doors Using Dynamic Pressure, which evaluate how well the panels withstand water pressure under changing field conditions. These tests ensure that IMPs can maintain their air- and water-tight integrity, even in harsh weather conditions.

Fire and durability testing

IMPs are designed to meet stringent fire resistance and durability standards, making them suitable for a variety of building types, including those in high-risk environments such as hurricane-prone areas. The fire performance of IMPs is tested using various methods, including ASTM E84, Standard Test Method for Surface Burning Characteristics of Building Materials—also known as the Steiner Tunnel test—for flame spread, ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials, for structural integrity under fire exposure, and NFPA 285, Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components, for full-scale facade fire testing.

The NFPA 285 test, in particular, is critical for assessing vertical and lateral flame spread on the exterior of a building. This test simulates a fire breaking out near a window and exposes the entire cladding system to a fire for 30 minutes, measuring factors such as flame spread, temperature rise, and mechanical failure of the facade. IMPs are required to pass these tests to ensure they meet stringent fire safety standards for multi-story buildings.

IMPs are also tested for impact resistance, such as the Miami-Dade Notice of Acceptance (NOA) test, which simulates the effects of hurricane debris impacts. These include the launch of large projectiles, such as 2×4 lumber members, as well as smaller debris intended to replicate gravel and roof aggregate commonly generated during severe storm events.

After impact testing, the assembly is further evaluated for air and water penetration, verifying that the enclosure maintains its performance even after sustaining damage. This combination of structural overload, missile impact and post-impact air and water testing distinguishes the Miami-Dade NOA test from many other durability evaluations. It is essential for buildings in tornado- and hurricane-prone regions. IMPs that pass these tests provide assurance of their durability and resilience under extreme conditions.

In addition to hurricane and impact testing, IMPs are often evaluated against Factory Mutual (FM) standards, which are widely used by insurers to assess risk in large industrial and warehouse facilities. Standards such as FM 4880, Approval Standard for Class 1 Fire-Rated Insulated Wall or Wall and Roof Panels and FM 4882, Approval Standard for Interior Finish Materials, are considered among the most stringent benchmarks for fire performance of panelized systems.

Design considerations for IMPs

Structural considerations

IMPs, while providing excellent thermal and weather protection, do not contribute to the structural integrity of the building. Instead, the structural framework of the building—typically steel framing—supports the loads and forces acting on the structure. IMPs
are designed to transfer wind loads to the structural framework while maintaining the integrity of the
building envelope.

IMPs have defined span capabilities based on product type, panel gauge, core thickness, and specified design loads. These span limits must align with support conditions to ensure proper performance.

Span tables define the maximum allowable support spacing based on the panel (type, configuration, and facer gauge), load type, fastener type, and configuration and deflection limits. Span tables are developed from structural testing (ASTM E72, Standard Test Methods of Conducting Strength Tests of Panels for Building Construction) and validated engineering analysis.

By decoupling envelope performance from structural capacity, IMPs enable more efficient and flexible structural design. This allows architects and engineers to optimize framing systems without compromising enclosure integrity.

Detailing for performance

Effective detailing is crucial for the long-term performance of an IMP system. Proper detailing ensures the building envelope remains air- and water-tight, and thermally efficient throughout the building’s life. Special attention should be given to areas where panels meet at corners, windows, doors, and roof intersections. Detailing at these intersections is critical to prevent water ingress, air leakage, and thermal bridging.

Manufacturers typically provide a library of standard details for common construction scenarios. However, specifiers should work closely with manufacturers to develop custom details for unique conditions, ensuring the IMPs perform as expected in all parts of the building.

Compliance with building codes

Evolving code requirements

As building codes continue to evolve, the demands on materials and systems, such as IMPs, become increasingly stringent. One of the most significant changes in recent years is the growing requirement for whole-building testing. Whole-building testing involves evaluating the entire building envelope as a system rather than testing individual components, such as windows or walls. This shift requires specifiers to ensure their building envelopes meet comprehensive performance standards, including air, water, and thermal control.

IMPs are well-positioned to meet these evolving code requirements, as they are tested as complete systems and have been shown to perform reliably across a wide range of conditions. Specifiers should stay informed about changes in local codes for the markets they operate in.

Meeting structural and thermal standards

In addition to meeting fire safety and impact-resistance standards, IMPs must comply with structural and thermal performance standards set forth in national codes. The American Society of Civil Engineers (ASCE) Chapter 7 provides prescriptive guidelines for calculating the live, dead, and wind loads that a building structure must withstand. IMPs must be integrated into the structural design to ensure they meet these load-bearing requirements, especially in areas with high wind or seismic activity.

Additionally, IMPs offer significant efficiency advantages. By integrating thermal control into the panel system, IMPs can help meet energy codes and reduce a building’s overall carbon footprint. Specifiers must ensure that the correct panel thickness is chosen to meet both energy code requirements and long-term thermal performance.

Including IMPs in construction documents

When specifying IMPs for a project, it is important to include detailed and accurate information in the construction documents to ensure compliance and performance.

• Section 1—General conditions of the contract, including sustainability requirements and building warranties.
• Section 7—This section should describe the performance requirements of the panels, including the required values for air, water, and thermal leakage. Additionally, include the tests that the panels must pass. Some manufacturers provide model templates for structuring these specifications, which can be adapted to the specific needs of the project.

Specifiers should also ensure the construction documents clearly outline the expectations for detailing, particularly at panel intersections and transitions. This will ensure the IMP system functions as intended throughout the building’s lifespan.

Conclusion

IMPs offer a comprehensive solution for modern building construction, providing high performance in thermal efficiency, air and water control, fire resistance, and durability. Their integrated design simplifies the construction process and reduces the number of trades involved, resulting in faster build times and fewer opportunities for error. By understanding the technical specifications, design considerations, and code compliance requirements, specifiers can confidently incorporate IMPs into their designs, ensuring long-term performance. As building codes evolve and demand for efficient, resilient structures increases, IMPs will remain an essential component of the modern construction landscape.

Author

David W. DeWulf, Ph.D., is director of business development for Kingspan Insulated Panels North America. DeWulf brings more than 30 years of experience in sales, marketing, and product development within the building envelope industry. He has a deep understanding of the vital role that moisture and thermal control play in ensuring the performance and sustainability of modern construction practices. DeWulf was a developer of the first drainage wrap in the industry as well as the first non-perforated, woven microporous wrap.