Fire-Resistant Coatings for Exposed Steel Building Frames

t484-6

Exposed steel frames are usually protected with intumescent coatings, which swell into an insulating char when heated, or with cementitious spray or board systems for higher fire ratings. The right choice depends on the required fire-resistance period, the section sizes, and the visual finish the architect wants. Always confirm the required rating with the fire engineer and building authority before ordering.

Why exposed steel needs fire protection

Steel keeps most of its strength at normal temperatures but loses stiffness and load capacity quickly when heated during a fire. Fire codes therefore often require structural members to keep their load-bearing function for a set period, even when the frame is left exposed for architectural reasons.

The protection you choose must match the fire-resistance period set by the engineer and the regulator. Some projects need only a thin film, while others need thicker, more robust layers.

Intumescent coatings for exposed frames

Intumescent paints are the most common solution when the steel should remain visible. When exposed to heat they expand into a porous foam layer that insulates the metal and slows its temperature rise.

Suitable for thin profiles and visible architectural finishes
Available in a range of colors and sheen levels
Thickness is set by section size and required rating

Intumescent systems need a clean, primed surface and a dry environment to perform as tested.

Cementitious spray and board systems

For longer fire-resistance periods, or where the frame is heavy and the coating can be more bulky, cementitious sprays and fire boards are often used. They are less decorative but very robust and tolerant of impact.

These systems are generally applied in a separate stage and may need to be concealed or finished with a plaster or paint layer. Discuss with the architect early, since they change the look of the frame.

How the factory process supports fire protection

At our workshop at 37 Rival Street, Tel Aviv, we prepare steel to the coating supplier's requirements before any protection is applied. That means cutting, welding and grinding are finished first, weld spatter is removed, and surfaces are cleaned and primed as specified.

Coatings are applied in controlled conditions where possible, which helps the film reach its specified thickness. Accurate drawings also show which members need protection and which connections are involved.

Coordinating with the engineer and fire authority

Fire protection is a design decision, not just a finish. The structural engineer defines the load and the required period, and the fire specialist confirms the tested system that meets it. Your contractor and our team then align the steel fabrication schedule with the coating schedule.

Ask for documentation of the tested system so the inspector can verify it on site. We can help prepare steel drawings that clearly mark the protected elements.

Maintenance and inspection over time

Intumescent and other protective films can be damaged by impact, moisture or later painting with incompatible products. Inspect the coating after installation and after any construction work nearby, and repair damaged areas using the manufacturer's approved method.

Keep a record of the coating type and thickness so future renovations can respect the original protection.

Frequently asked questions

Can an exposed steel frame be left unprotected?

Only if the fire engineer and local authority confirm that the required fire-resistance period is met without added protection. Many commercial buildings do need protection, so check this early.

How do I know which coating thickness is required?

The thickness depends on the section size, the required fire rating and the tested product. Your fire engineer or coating supplier will provide the specification for each member.

Will intumescent paint change the look of the steel?

It can be finished in a range of colors and sheens, so the frame can still look visible and architectural. Discuss the desired appearance with the architect before selecting the system.

Do you handle both the steel fabrication and the coating preparation?

We fabricate custom steel frames and prepare the surfaces for coating, and we coordinate the process with your engineer and coating applicator. Please confirm the final protection method with the fire specialist.

Common mistakes to avoid

A common error is choosing a coating by appearance alone and only checking the fire rating later. Confirm the required period and tested system before the steel drawings are finalized.

Our recommendation

Involve the fire engineer, architect and steel fabricator at the design stage so the chosen coating, section sizes and connections work together. Share your drawings early and request written confirmation of the required protection for each member.

Summary

Fire-resistant coatings for exposed steel frames range from intumescent paints for visible finishes to cementitious systems for longer ratings. Choose based on the required fire period, section sizes and desired look, and confirm everything with your engineer and authority.

השאירו פרטים ונחזור אליכם