Exentec US Achieves First FM Approval for Large-Diameter Fume Exhaust Ducts Under Updated Safety Standard

Exentec US, Inc. has achieved certification under the newly revised FM Approvals 4922 standard, making it the first U.S. manufacturer to receive FM Approval for duct systems exceeding 60 inches in diameter. This milestone demonstrates the company's leadership in safety and engineering excellence within the fume exhaust duct system industry. The certification covers Exentec's Fab-Tech PermaShield™ duct systems across unrestricted diameters, sizes, and vertical riser heights, enabling facility owners and engineers to construct larger duct systems such as mains and submains with FM Approved products.

Jim Howard, General Manager of the Exhaust and Abatement team at Exentec, stated that this certification reflects the company's dedication to engineering excellence and proactive approach to evolving safety standards. The achievement reinforces Exentec's role as a trusted partner for clients seeking high-performance, compliant solutions. FM Approvals, a globally recognized certification organization, recently updated its 4922 standard to strengthen fire safety and performance requirements for duct systems. The revision introduces distinct Fire Propagation Index (FPI) classifications for both 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 March 2025 revision now mandates a separate FPI rating for the interior liner, ensuring that both external and internal components meet elevated safety thresholds. This update is particularly relevant for single-wall constructions, where the duct wall material itself must comply with the new criteria. These enhancements reflect a growing industry focus on rigorous safety standards and property loss prevention. The updated FM 4922 standard and Exentec's certification underscore a shared commitment to advancing duct system reliability and performance.

Clients can now benefit from products that not only meet but exceed the latest safety expectations, backed by proven innovation and trusted compliance. For more information about Exentec's products and services, visit https://www.exentec.net. This development represents a significant step forward in industrial safety, providing facility operators with certified solutions for large-scale fume exhaust systems that adhere to the most current safety protocols available in the market today.