Importance of Structural Fireproofing

Learn why structural fireproofing is essential for fire safety and emergency response. Explore fire-resistant materials and strategies for building protection.

Disclaimer: While no home can be completely fireproof, many homeowners and citizens commonly use the term “fireproofing” when referring to fire-resistant practices. For clarity and accessibility, we have used this term throughout the article, though the more accurate term is “fire resistance.”

What is Structural Fireproofing

Structural fireproofing is a method of using fire-resistant materials and techniques to increase a building’s ability to withstand fire. Fireproofing can help in keeping people and property safe by preventing the spread and severity of fire and smoke within a structure. The process of structural fireproofing can include using fire-resistant building materials for items such as doors, windows, framing, and insulation, as well as fire-resistant coatings, sealants, and barriers.¹

Types of Structural Fireproofing

Structural fireproofing can be achieved through active fireproofing and passive fire protection.

Active Fireproofing refers to actions and products that are meant to recognize and subdue fire. Active fireproofing methods can provide detection, suppression, ventilation, or evacuation. The commonality among all of these systems is that they are all activated by motion or action, making them ‘active’ fireproofing.²

• Detection products are used to notice smoke, heat, or flames, and then alert people to the presence of those dangers. This could include fire alarms or smoke detectors.
• Suppression systems can be automatically activated, such as a sprinkler system, or actively used by an individual, such as a fire extinguisher.
• Ventilation includes automated fans and vents, which can move smoke from rooms or passageways to allow people to safely leave a building.
• Evacuation systems assist occupants in exiting a structure, and may include intercoms or emergency lighting.²

Passive Fire Protection refers to structural designs and processes that are utilized to suppress the spread of fire and minimize the risk of damage. One example of passive fire protection is separating structures into smaller spaces to reduce the passage of smoke and flames in the event of a fire. This is known as compartmentation. Fire doors are another common form of passive fire protection, often used in conjunction with compartmentation to delay the spread of fire between rooms or passageways. Another example is using reinforced structural elements for load-bearing, such as beams or columns, to provide extended fire resistance.²

Fireproofing Materials

Many fire-resistant materials are available for structural fireproofing, including concrete, brick, steel, cast iron, stone, gypsum, stucco, glass, and insulation.

Concrete is extremely fire-resistant, tolerating temperatures as high as 1000C for one hour before it is compromised.³ Concrete is highly resistant to fire because it is non-toxic and non-combustible. It also has low thermal conductivity and does not easily react with other materials or transfer thermal energy. Because of these characteristics, it is one of the safest materials for building a fire-resistant structure.⁴

Brick can resist heat at a very high level.6 Generally, bricks are able to withstand temperatures of up to 1200C. The mortar commonly used to affix bricks together is not as fire-resistant, as significant increases in temperature can result in cracking or expanding. However, brick remains a widely used fire-resistant building material.³

Steel has long been used in the construction of buildings due to its strength and structural integrity, but it is not as able to withstand high temperatures as other materials. Steel can be stressed at temperatures higher than 600C and can completely melt at 1400C.³

Cast iron itself is not often used in construction due to its potential to shatter after exposure to heat. However, it can be covered with concrete, bricks, or other more fire-resistant resources.³

Stone can sometimes react poorly to heat, depending on the type. Granite can explode after exposure to high temperatures, and limestone can crumble. However, sandstone is better at enduring fire conditions due to the unique way it is formed.³

Gypsum board provides consistent fire resistance for interior finishes. Type X gypsum board has additives that increase its fire resistance and a slow-burning exterior paper. Gypsum board also has a noncombustible core that releases steam when exposed to fire. This steam reduces heat transfer through the board. Multiple layers of gypsum board can be used to improve a building’s ability to resist fire.⁵

Stucco is a plaster made of sand, lime, and cement and can be applied to any building material like wood or brick. It is heavy-duty and fire-resistant; applying a layer of stucco 1-inch thick to a ceiling or wall can provide a 1-hour fire rating.⁵

Glass has similar properties to stone and may shatter or crack after heating and cooling. For this reason, glass is often reinforced or laminated to increase its fire resistance when used in construction.3 Double-paned glass is another option to improve the fire resistance of windows in a structure.⁵

Insulation can add to a building’s fireproofing depending on the material with which it is made. Standard sheets of fiberglass insulation can handle heat as high as 220. Mineral wool, including glass wool, slag wool, or rock wool, is another option for insulation due to its noncombustibility. Glass wool can resist temperatures up to 1,220. Foam insulation is a third type that can be used for its fire-resistant properties. With a flame retardant, it can withstand temperatures up to 300*.⁶

Fireproof Coatings

There are two primary types of fireproof coatings that can be applied in the construction process to increase the fire resistance of a structure: Cementitious coatings and intumescent coatings.¹

Cementitious coatings have properties of cement and are one of the primary ingredients used to make concrete. Cementitious coatings come in two forms; hydraulic cement and supplementary cementitious materials. Both forms of cementitious coatings are highly fire-resistant due to their inherent properties.⁷

Intumescent coatings are another option for fireproofing. When exposed to extreme heat, intumescent paint expands and bubbles, increasing in volume which creates an insulating layer. This material is cost-effective and easy to apply in multiple coats, with each layer increasing the level of fire resistance. 350mm of intumescent coating has a fire rating of 1.5 hours, while 700mm has a fire rating of 3 hours.⁷

Structural Fireproofing in Preplanning

Structural fireproofing is an important part of fire preplanning. Employing purposeful techniques and materials for both active fireproofing and passive fire protection reduces the risk of property damage and increases firefighter safety and effectiveness. Improved fire resistance allows occupants and firefighters more time to evacuate a building safely by slowing the spread of smoke and fire.8 This reduces the risk of injury from burns and smoke inhalation, as well as the risk of death.9 In addition to increasing personal safety, structures that have been fireproofed are less likely to suffer from damage as the slower spread of fire and smoke increases the effectiveness of firefighting efforts.

Ideally, fire preplanning will involve coordination between fire departments, builders, owners, occupants, insurers, and designers. The NFPA recommends the evaluation of the following factors when preplanning: construction, occupant characteristics, protection systems, capabilities of responding personnel, mutual aid availability, water supply, and exposure factors. Being familiar with any active fireproofing or passive fire protection systems utilized in a building can assist fire departments in preparing the best way to respond in an emergency. The more information a fire department has, the more effectively it can serve the community.¹⁰