Fireproofing 101 Guide

Introduction to Fireproofing

Fireproofing is a critical part of building a home or business. Fire will always cause damage, but fireproofing can help prevent your property from becoming a total loss. 

We should note that nothing is really “fireproof.” Materials that have been fireproofed are actually fire-resistant. They can still burn, it will just take longer and the material may burn slower. 

Fireproofing helps raise the temperature at which certain materials, like steel, become incapacitated. It can help prevent destruction from fire for up to two or three hours. 

Some fireproofing materials also help prevent the creation of toxic smoke during a fire. That’s helpful because smoke kills more people in a fire than the flames, even when it isn’t full of toxins.

Not only is fireproofing a good idea, but it’s often required to meet building codes or insurance regulations. Before starting any building project, you should find out what building codes and regulations you must meet to fireproof the building. That will save you hassle down the road when you get inspected. 

Brief History

Up until World War II, dense concrete was used to protect steel in processing facilities from fires. Concrete was inexpensive and able to withstand high temperatures caused by fires. 

This heavy concrete posed a problem, however, because you needed to add extra steel to the project to compensate for the extra weight of the concrete. Additionally, concrete spalls when it gets hot, meaning it needs to be replaced after a fire. 

Eventually, traditional concrete was replaced with cementitious coatings. While the coatings themselves were inexpensive, the amount of labor required to apply the coatings became prohibitively expensive. Cementitious coatings also lost stability and strength after a fire and needed to be replaced.

Now, intumescent paint is becoming the preferred product for fireproofing steel and other construction materials. Intumescent paint foams up when it reacts to heat. That creates a low-density but high-volume coating that can protect structural steel for as long as two to three hours during a fire. 

 Why is Fireproofing used?

Fireproofing is used to buy time to put a fire out before structural damage happens to a building. Steel, in particular, begins to lose strength at 570 degrees Fahrenheit. However, a fire in a refinery plant can reach 2000 degrees. 

Fireproofing is a passive way to protect a building from fire. It won’t put out a fire like sprinklers or other active fire suppression methods. However, fireproofing will help increase the amount of time you have to fight a fire before the structural integrity of a building is compromised.  

It’s important to note that fireproofing a material doesn’t make it entirely resistant to fire. Fireproofing relates to measured performance under specific conditions of testing and evaluation. It’s also used to de-escalate a fire that overheated pressure vessels or collapsing structural materials could cause. 

In short, fireproofing can’t stop a fire, and it won’t necessarily stop materials from burning. However, it does buy time for firefighters to beat back a blaze and can minimize the damage that results from a fire. 

What Are the Differences Between Passive and Active Fire Protection?

When looking at fireproofing your home or business, you should look at installing both passive and active fire protection systems. What are the differences?

Passive fire protection involves fireproofing materials to help make them resistant to fire. Passive fire protection can help slow the spread of a fire and protect building materials. However, it doesn’t do anything to help put out the fire. 

Active fire protection involves things like automatic sprinklers to help put out a fire. As the name implies, these systems actively work to stop a fire.

As you can see, each type of fire protection has an equally important, but very different, purpose. That’s why you should include both passive and active fire protection in your construction. Active fire protection helps stop a fire, while passive fire protection helps minimize the damage from a fire. 

Fireproofing Applications: Common Uses

Fireproofing has many common uses from residential fabrics to commercial buildings. 

The main goal of fireproofing is to slow the spread of fire and help reduce damage caused by a fire. 

The most common use for fireproofing is in petrochemical refineries, where fires can reach more than 2000 degrees. Fireproofing helps protect the steel structure from collapsing and making the fire worse. That can mean the difference between fixing a structure after a fire and needing to rebuild it from scratch. 

Of course, fireproofing can and should be used for any building project, whether commercial or residential. Some building codes, localities, and insurance companies even require fireproofing that meets certain regulations. 

It’s even possible to fireproof soft materials like curtains and clothing. It won’t necessarily prevent the material from burning. However, the added resistance to fire helps buy enough time for the fire to be put out. 

Sprayed Fire-Resistive Material (SFRM) (Fireproofing Sprays)

SFRM typically starts with a base of cement or gypsum. Other materials are often added to it, including things like:

  • Quartz
  • Mineral wool
  • Vermiculite
  • Perlite
  • Lightweight polystyrene beads
  • Chemical additives 

Most of these additives serve to lighten the density of or add insulation to the gypsum or cement. Other additives harden the mixture faster or harder than normal. The additives will vary depending on the needs of the project.

Composition of SFRM

Sprayed fire-resistant material (SFRM) is typically sprayed onto structural building materials to render them resistant to fire. SFRM is commonly cementitious or mineral-fiber-based. However, intumescent paint is becoming increasingly common. 

SFRM can be troweled on or applied as a wet or a dry spray. It’s delivered as a powder in a bag and must be mixed with water on site. Anybody who handles SFRM – either mixing or applying it – must wear proper eye and lung protection. 

It’s important to note that SFRM should not be used in wet or very humid environments. Moisture may cause mold growth and deteriorate the product. 

Structural Steel

Structural steel is not fireproof by itself. In fact, it starts to degrade around 570 degrees Fahrenheit. That’s why it needs to have SFRM or other fireproofing added to it to increase its fire resistance. Fireproofing helps steel stay strong at higher temperatures for longer periods of time than leaving the steel bare. 


Concrete works very well to fireproof steel and other building materials. However, concrete can be very heavy and may spall (break off in chunks) during a fire. Reinforcing the concrete can help reduce the size of chunks that spall during a fire, meaning you will have less concrete to replace after the fire.  

Another problem with concrete is that it may hide corrosion of the steel it’s protecting. This seems to happen more often in marine environments. 

Intumescent Paint

Intumescent paint is the latest product being used to fireproof building materials. It only needs to be applied in a fairly light layer (as little as half a centimeter thick). However, it expands when it gets hot and provides a thick coating over the building material during a fire. 

 Commercial vs. Residential Fireproofing

The primary difference between commercial and residential fireproofing is what materials are being fireproofed.

In commercial fireproofing, the structure of the building, usually steel, is the primary focus for fireproofing measures. The goal is to keep the building structure as secure as possible for as long as possible while a fire burns. It doesn’t really help stop the spread of fire; its purpose is to protect building materials during a fire until it gets put out. 

In residential fireproofing, the goal is to make the interior of the home fire resistant to help prevent the spread of fire within the home. Fireproofing inside your home can slow the spread of a fire if you have fewer items that will readily burn. Fireproofing a home can make the difference between losing your kitchen to a fire and losing your entire house to a fire.  

Fireproofing Contractors

Finding a reputable fireproofing contractor is crucial. There are a lot of regulations and codes that must be followed. Improper fireproofing could fail an inspection or cause your property to fail a fire inspection. 

Look for fireproofing contractors that are certified and accredited through an organization like the National Fireproofing Contractors Association (NFCA). You should also always do your due diligence and check the contractor’s reviews and Better Business Bureau (BBB) rating to prevent being scammed.

Regulations and Codes

There is a wide variety of codes and regulations you must follow when applying fireproofing materials. Just for starters, there are local, state, and national codes regarding fireproofing. There are different regulations for fireproofing building materials versus soft interior materials, like curtains.  

The National Fireproofing Association (NFPA) publishes more than 300 consensus codes and standards. That’s a good place to start when looking at fireproofing codes and regulations. However, state and other local regulations may trump the NFPA codes. 

Most places use the International Building Code (IBC) to create their own standards. This code is updated every 3 years and was just updated in 2018. 

You should always follow the strictest fireproofing code in your area. 

Restrained Vs Unrestrained Structures

Some structures can be designed as restrained structures. That is to say, they can resist substantial thermal expansion under the full range of temperatures expected in a fire. 

For a structure to be designated as restrained, a structural engineer must label the building as restrained in the plans. Then, proof must be provided that the structure meets all the requirements of a restrained structure. 

All other structures are considered unrestrained, and they may need additional fireproofing compared to restrained structures. 

 Alternative Fireproofing Methods

We have mostly discussed cementitious and intumescent fireproofing materials here, but they aren’t your only options. Alternative fireproofing methods include:

This has the added advantage of acoustic, pest, and termite control. The boards can be applied as you go, cut to size, and may include decorative finishes.

These are great for handling unusual shapes and meet most fire codes. They’re easy to install and help prevent the release of toxins during a fire. Unfortunately, there aren’t many manufacturers making flexible blankets.

This is one of the oldest types of fireproofing. It involves installing hollow structural members and using running water, antifreeze, and a rust inhibitor. The water will absorb heat and be replaced with cool water in a continuous cycle.

Durability of Fireproofing Materials

Fireproofing materials need to provide more than just fire protection, especially in commercial settings. Fireproofing materials must also be durable. They have to withstand everyday rigors like outdoor weathering; mechanical abuse; or exposure to chemicals, solvents, or oil for several decades. 

After all, what good is a fireproofing material if it degrades from everyday use before it’s required in a fire? That’s just another reason companies are always working to create the best fireproofing materials. 

Test Methods and Required Time Rating

Testing of fireproof materials takes place in controlled settings. It can’t accurately replicate real-world scenarios. However, it is useful for comparing the relative ability of something to withstand fire for a certain period of time. 

Different types of materials may require different levels or types of fireproofing. For example,

  • Structural steel might require a fire test rating of 2-3 hours. Gunite or concrete at minimum thicknesses of 2”-3” are the most common fireproofing materials for this application. 
  • Plate and frame exchangers have rubber gaskets between plates. For these parts, a protective enclosure surrounds the vulnerable area. It should be able to withstand high temperatures for around an hour. 
  • Steel vessels may need protection for 1-2 hours. 1.5”-2” of gunite is often used for this purpose. Sometimes fireproofing materials are combined with thermal insulating materials. 
  • Electrical and pneumatic components (like valve actuators, manual initiators, cable, aboveground wiring, and conduit) required for depressurization, emergency isolation, and process shutdown usually have a fireproof rating of 15-20 minutes so they have time to work at the start of a fire.