JFE Steel has developed a fire-resistant coating reduction method that can reduce the thickness of fire-resistant coatings on H-shaped steel beams in buildings by up to approximately 40% compared to conventional methods (*1), and has obtained the Minister of Land, Infrastructure, Transport and Tourism certification for a 1.5-hour fire-resisting structure (hereinafter referred to as the 1.5-hour fire resistance certification). (*2)

In recent years, labor shortages on construction sites and soaring material costs have become more acute, so making greater efficiency and rationalization in building construction are more important than ever. “JFE’s Fire-resistant Coating Reduction Method”, developed in 2016, is designed for use with steel pipe columns. (*3) Reducing the thickness of the fire-resistant coating allows for smaller column dimensions, which increases the usable interior space, and reduction of labor and costs for installation at construction sites. Consequently, it has been widely adopted for use in various buildings, including offices, commercial premises, schools, and hotels.

In response to customer requests, we have obtained a 1.5-hour fire resistance certification for H-shaped steel beams using this construction method, which was previously only applicable to steel pipe columns. This method focuses on the thermal capacity of steel members and fire-resistant coatings. Specifying the cross-sectional dimensions of steel members to meet the required fire resistance performance achieves a significant reduction in the thickness of the sprayed rock wool fire-resistant coating material. The newly acquired 1.5-hour fire resistance certification enables the thickness of the fire-resistant coating to be reduced from 45 mm to 25 mm when using our H-shaped steel beams (*1). A through hole (with a diameter of up to half the height of the beam) can also be provided. Using this method for both our H-shaped steel beams and steel pipe columns will lead to further labor savings and cost reductions.

JFE Steel is advancing our ’JFESCRUM^®’ initiative (*4) to provide the construction industry with one-stop solutions to its diverse challenges. Going forward, we will continue to promote development and facilitation of steel products and utilization technologies that achieve the rationalization of construction and contribute to the realization of a sustainable society.

*1 Fire-resistant coating involves covering steel columns and beams in highly fire-resistant, insulating materials, such as rock wool, to prevent deformation and collapse due to heat during a fire. When rock wool is sprayed on as the fire-resistant coating, the standard thicknesses are 25 mm for a one-hour fire-resisting structure, 45 mm for two hours, and 60 mm for three hours. However, we have now obtained Ministerial Certification to achieve a 1.5-hour fire-resisting structure for H-shaped steel beams using only 25 mm of fire-resistant coating, whereas the conventional standard was to use 45 mm for a 2-hour fire-resisting structure (Figures 1 and 2).

*2 FP090BM-0845, FP090BM-0862
Fire-resisting structure refers to structures that have the necessary fire resistance to prevent collapse and the spread of fire. The required duration of fire resistance varies depending on the section of the building and the number of stories. The required fire resistance duration for columns and beams is as follows:
One hour: The top floor and up to four stories directly below it
1.5 hours: Fifth to ninth floors counting from the top floor
Two hours: Tenth to 14the floors counting from the top floor

*3 An overview of the “JFE Fire-Resistant Coating Reduction Method” for steel pipe columns.
- News Release for May 25, 2016
https://www.jfe-steel.co.jp/release/2016/05/160525.html
- JFESCRUM^®　HP
https://www.jfe-steel.co.jp/products/infrastructure/jfescrum/interview2.html

*4 This is our integrated solutions brand for customers in the construction sector. In response to significant social changes in recent years, we have brought together the technological capabilities of the JFE Steel Group to provide swift, one-stop support — from research and development to manufacturing and technical support — to help the construction industry overcome various challenges.

[Figure 1] Overview of JFE’s Fire-resistant Coating Reduction Method for H-shaped Steel Beam

Cross-section of H-shaped steel beam Thickness of fire-resistant coating for H-shaped steel beam
(conventional method ⇒ certificated method)

Required fire-resistant time	Sprayed rock wool
1.5 hours	45mm⇒25mm

[Figure 2] Scope of H-shaped steel beam
This method applies to JFE Steel H-shaped beams with a fixed outer dimension (Super Hislend H) and welded assembly H-shaped section beams with the following dimensions:
1.5-hour fire resistance (*5) : H－400×200×12×19 or higher

*5 In the case of ALC composite fire resistance: H－400×200×9×19 or higher

Standard for rolled H-shaped steel beams “Super Hislend H” for structural use

Brand	Grad	Flange thickness mm	Yield point N/mm2	Tensile strength N/mm2	Yield ratio %
SN490	－	6 to 100	325 to 445	490 to 610	80 or lower
HBL®-H355	MSTL-0314	32 to 40	355 to 475	520 to 640	80 or lower

Fire-resisting structure of beam alone

Required fire resistance time	Fire resistant coating
	Sprayed rock wool
1.5 hours	FP090BM-0845

Composite fire-resistant structure with outer wall

Outer wall	Required fire resistance time	Fire resistant coating
		Sprayed rock wool
ALC*6	1.5 hours	FP090BM-0862

*6 Reinforced concrete slab and PC slab are also acceptable.

About JFE Steel Corporation

JFE Steel Corporation, one of the world’s leading integrated steel producers, was established through the consolidation of NKK Corporation and Kawasaki Steel Corporation in 2003. The company operates several steelworks in Japan and numerous branch offices and affiliates throughout the world. Under the corporate vision of “contributing to society with the world’s most innovative technology,” JFE Steel leverages world-class technologies and know-how to produce a wide range of products. The company reported consolidated sales of 3,716 billion yen and consolidated crude steel output of 24.80 million tons in the fiscal year ended March 2023.

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