Exentec US, Inc., a leading innovator in fume exhaust duct systems, has achieved a significant milestone by becoming the first U.S. manufacturer to receive FM Approval for duct systems exceeding 60 inches in diameter under the newly revised FM Approvals 4922 standard. The certification applies to the company's Fab-Tech PermaShield™ duct systems across unrestricted diameters, sizes, and vertical riser heights, allowing facility owners and engineers to construct larger duct systems such as mains and submains with FM Approved products.
The updated FM 4922 standard, revised in March 2025, introduces distinct Fire Propagation Index (FPI) classifications for both the exterior and interior surfaces of ductwork, with new testing protocols specifically targeting systems above 60 inches in diameter. Previously, the standard applied a unified FPI requirement across the entire duct system. The revision now mandates a separate FPI rating for the interior liner, ensuring that both external and internal components meet elevated safety thresholds—a critical update for single-wall constructions where the duct wall material itself must comply with the new criteria.
Jim Howard, General Manager of the Exhaust and Abatement team at Exentec, emphasized the importance of this certification: "We are proud to be at the forefront of industry progress. This certification reflects our dedication to engineering excellence and our proactive approach to evolving safety standards. It also affirms our role as a trusted partner for clients seeking high-performance, compliant solutions."
FM Approvals is a globally recognized certification organization known for rigorous testing and certification of property loss prevention products. The revision of the 4922 standard strengthens fire safety and performance requirements for duct systems, reflecting a growing industry focus on safety and loss prevention. Exentec's early compliance demonstrates its leadership in adapting to these enhanced standards.
For facility owners and engineers, the availability of FM Approved large-diameter duct systems means that critical infrastructure can now be constructed with components that meet the latest safety expectations. This development is particularly relevant for industries such as semiconductors, life sciences, and data centers, where fume exhaust systems are essential for maintaining safe and clean environments.
Exentec's certification underscores the company's commitment to innovation and safety, providing clients with products backed by proven engineering and trusted compliance. As the first U.S. manufacturer to achieve this milestone, Exentec sets a new benchmark for the industry, ensuring that its PermaShield™ duct systems not only meet but exceed the latest safety requirements.
