Hyundai Steel wins Korea's first KS certification for fire- and quake-resistant H-beam

Hyundai Steel said Thursday its fire- and seismic-resistant structural H-beam, the SHN355FR, has received KS certification under the hot-rolled structural steel standard KS D 3866.

The company said its Incheon factory is the first facility in South Korea to earn KS certification for a fire- and seismic-resistant H-beam under the revised KS D 3866 standard.

The SHN355FR is a steel product with a yield strength of 355 MPa — the maximum stress a material can withstand while returning to its original shape after an external force is removed. Beyond that threshold, permanent deformation occurs. The product can bear a load of roughly 36 kilogram-force per square millimeter or more.

The steel is designed to maintain the deformation capacity and seismic performance required during an earthquake while also retaining its strength in a fire. The company said the material preserves more than 67 percent of its room-temperature yield strength even when the steel temperature rises to 600 degrees Celsius, ensuring structural stability in fire conditions.

The certification follows the KS D 3866 standard revised and promulgated by the Korean Agency for Technology and Standards in July 2024. The updated standard added fire- and seismic-resistant steel grades — designated SHN-FR, with yield strengths ranging from 355 to 460 MPa — as a new national standard alongside the existing seismic-only SHN grades.

As buildings grow taller and larger, technology that addresses both fire and seismic risks has become increasingly important. Hyundai Steel said it has focused on developing steel with fire-resistant properties, building on its accumulated expertise in seismic steel.

The company expects that using fire- and seismic-resistant steel in buildings will improve safety against both hazards. It also anticipates shorter construction timelines, as the material reduces the amount of fireproofing coating needed and simplifies the construction process.

Hyundai Steel developed its SHN hot-rolled structural H-beam in 2005 and has continued research and development in seismic steel, subsequently releasing high-performance structural products including SD500S- and SD600S-grade ultra-high-strength seismic rebar and the SHN460. In 2017, the company launched its seismic steel brand, H CORE.

Hyundai Steel plans to gradually expand the strength grades and thickness range of its steel products, and said it will also invest in developing manufacturing technology that delivers both performance and cost efficiency.

"Becoming the first in South Korea to obtain KS certification for the SHN355FR is official recognition of the fire- and seismic-resistant steel technology and manufacturing capabilities Hyundai Steel has built up over many years," a company official said. "We will continue to raise the bar in fire- and seismic-resistant structural steel through ongoing research and development and quality improvement, contributing to a safer built environment."

Meanwhile, Hyundai Steel recently held its "2026 AX Performance Sharing Conference" at the research center of its Dangjin steelworks. The event was organized to share the results of AI transformation initiatives employees pursued throughout the year and to identify and spread best practices. A total of 198 submissions were received through a call for entries that ran from August, comprising 58 from the manufacturing sector and 140 from other business operations.