Fireproofing Methods for Structural Steel

Steel fireproofing
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Many building codes require you to provide fireproofing protection to structural steel as a safety precaution during a fire event. In the U.S. the most common way to provide fireproofing protection is by spraying low-density fiber or cementitious compounds, now called Spray-Applied fire resistive material or SFRM. In addition to sprays, there are a couple of more options that can be considered and could be even better than the commonly used spray.

Steel Fireproofing: Spray

Fire resistance can be sprayed on the steel to provide heat resistance. The substances being applied can also be used over wood, fabric, steel and other building materials. When spraying the substances, once the key element is to provide the required thickness to meet building code requirements. Sprays are divided into 'Wet Spray' or 'Dry Spray' materials, describing how the material is mixed and applied.

Intumescent Coatings

Also known as intumescent paint, this is a method used to protect and provide fire resistance to structural steel members. One of the key benefits is that it will expand as much as 100 times the original thickness of the material, providing superior fire resistivity, creating a buffer type are between the fire and the steel members. It is a great solution when aesthetics come into place and steel is exposed to the general public. The product is applied just like paint, which every layer will add up to the overall thickness of the product.

This fireproofing material can be applied to structural wood as well.

Rigid Board Fireproofing

Rigid board fireproofing can be very easy and fast to install. One of the key benefits is that it could be installed as you go up installing the steel deck and beams. Not only will provide the right fireproofing requirements, but it will also provide great thermal and acoustic control.

It can be mechanically fastened and can prevent pests and termite attacks. It is normally available in different thickness to meet UL requirements. This type of fireproofing board can also withstand moisture and humidity without losing its fire stopping characteristics.

Flexible Blanket Systems

A flexible blanket can be used as fireproofing material, making it easy to install and to maintain a toxic-free environment in case of fire. Although a very practical and convenient method, there are only limited numbers of manufacturers. This application can meet almost all safety standards and codes providing a cost-effective and reliable system to prevent a fire from spreading to structural members.

There are some alternatives that fall into this category and can be classified as removable and reusable fireproofing blankets. Some of these blankets can be used in specific areas on which access could be important and needs to be maintained throughout the product life-span.

Autoclaved Aerated Concrete

These concrete blocks will enhance and provide longer fire resistivity when needed, especially around steel columns. Autoclaved aerated concrete can produce fireproofing characteristics when they are installed between the flanges and tied to the web of rolled sections.


When you need to have longer fire resistance requirements, then it would be great to pour concrete between the flanges of the steel components using shear connections attached to the steel web. The concrete being placed needs to be retained at the bottom of the connection area.