What Is Intumescent Paint?
When you’re responsible for a fire management strategy, every choice matters. Using intumescent paint is one way to mitigate damage from a fire.
But what is intumescent paint, exactly?
Intumescent paint and intumescent coatings passively increase a building’s resistance to fire. When exposed to extreme temperatures, these coatings expand. The intumescent paint forms a protective char around your asset that prevents fire damage.
The secret behind these coatings lies in their chemical makeup. An intumescent coating consists of many chemicals, all suspended in a binder. The binder softens in response to heat exposure, letting the suspended chemicals react. These chemicals produce a foam, which hardens into an insulating material or char.
If you need an intumescent paint that’s ASTM E-84 and E-119 compliant, we recommend FlameOff Coating’s Fire Barrier Paint for your next project.
Recommended Intumescent Paint: Fire Barrier Paint
FlameOFF Coatings (as the name implies) specializes in fire resistant paints and sprays, and they have knowledgeable staff that can answer all your questions.
FlameOFF is our recommended provider because:
- Their Fire Barrier Paint is ASTM E84 and E119 compliant
- The paint is low VOC and environmentally friendly
- The product works on a variety of materials including steel, wood, and drywall
- They’ve specialized in fire resistant coatings and have industry expertise
Their premier Fire Barrier Paint is the perfect coating for your next project.
Key features include:
- E84 compliant: Class A flame spread (tested and certified by a 3rd party lab)
- ASTM E119 compliant: 1 and 2-hour fire rated for long-lasting protection
- Compatible with steel, wood, gypsum, sheetrock, metal, and more
- Eco-friendly, low VOC, water-based intumescent coating
- Gold Supplier Member of National Fireproofing Contractors Association
Learn more about FlameOFF and Fire Barrier Paint.
How to Choose an Intumescent Paint Supplier
There are several things you need to consider when selecting an intumescent paint supplier:
- Fireproofing compliance: Are the intumescent formulas ASTM and UL certified? ASTM E119 (UL 263) and E84 (UL 723) are the most common standards for building materials.
- Environmental compliance: Are the products you’re purchasing environmentally friendly and EPA compliant? Look for low VOC, high solids, and water-based coatings if your facility needs to meet EPA standards.
- Material adhesion: Are the coatings designed specifically for the type of materials you’ll be painting (e.g. steel, wood, drywall, OSB, sheetrock, metal, etc.)?
- Expertise: Is your supplier knowledgeable in ASTM, NFPA, and UL codes and standards? You’ll want to order from a company with many years of experience in the fireproofing space with sales reps and engineers on standby.
- Membership: Is your paint supplier a member of fireproof organizations like the National Fireproofing Contractors Association (NFCA)? Membership in organizations like the NFCA ensure that your supplier’s team is investing in continued education around intumescent paint and other fireproofing technologies. The NFCA in particular requires all members to have at least two years and 20 jobs in the passive fireproofing business.
Intumescent Paint vs. Cementitious Paint
Intumescent coatings have become the de facto tool for passive fire protection, but there are two other types of coatings worth considering. The other categories in this field are dense concrete and lightweight cementitious fireproofing. Keep reading to understand the difference between intumescent and cementitious paint.
Lightweight cementitious coatings are cement-based products used to fireproof structures. Like intumescent paint, these coatings can stand up to very hot temperatures. As their name implies, they are much lighter than dense concrete.
That said, cementitious coatings have some notable drawbacks. One major problem – space between the substrate and the coating will develop over time. That space can become filled with moisture, encouraging corrosion. Cracking is a major issue with cementitious coatings, which is why proper surface preparation is so important.
| Cementitious Coatings | Intumescent Paints |
| More cost effective | More expensive |
| Not intended for visible areas of a building | Aesthetically pleasing |
| Coating can crack | Smoother finish |
| Heavy concrete | Lightweight formulation |
Because of these issues, cementitious coatings have lost popularity over time. Instead, intumescent fireproofing has become the go-to option for fire retardant paint today.
How Much Does Intumescent Paint Cost?
There’s both a short answer and a long answer to this question, but we’ll start with the long answer. Intumescent paint costs for your project can vary based on many factors. These factors include:
- Coating thickness
- Adhesion
- Required surface preparation
- Environmental resistance
- Expansion ratio (that is, how much a coating expands when exposed to high temperatures)
- VOC levels
With all that in mind, you can expect to pay anywhere from $4 to $12 per square foot of intumescent paint. The exact amount you’ll pay will depend on the factors listed above, among others. Still, it should be somewhere in that ballpark.
We’ve partnered with top-rated intumescent paint suppliers that can help you save big. Get a free consultation and talk with a qualified expert today.
Intumescent Paint Fire Ratings
There are lots of fire ratings out there, but which intumescent paint fire rating should you focus on? Two fire ratings are important to know about for intumescent fireproofing: ASTM E84 and ASTM E119.
ASTM E84
One important intumescent paint fire rating is American Society for Testing and Materials (ASTM) Test Method E-84, or “ASTM E84” for short. This rating focuses on a material’s flame-spread.
In ASTM E84 tests, a 20-inch by 25-foot material sample is installed on a test chamber’s ceiling. Testers then apply a gas flame to one end of the sample. The results of this test determine the material’s flame spread rating (FSR) on a scale of 0-200. Inorganic reinforced cement board has a rating of zero on this scale, while red oak has a rating of 100.
From there, materials fall into three classes. Class A materials have FSRs of 0-25, Class B materials have FSRs of 26-75, and Class C materials have FSRs of 76-200.
ASTM E119
While ASTM E84 deals with flame-spread, ASTM E119 is all about how long a material can deal with fire. For intumescent paint, “2 hour rating” and phrases like it may refer to this test.
For ASTM E119 testing, a material sample is exposed to a temperature-controlled fire. This test measures the reliability of structural elements like:
- Bearing walls
- Partitions
- Columns
- Floors
- Roofs
- Beams
- Protective membranes
Important note: Fire Barrier Paint from FlameOFF Coatings is ASTM E84 and E119 compliant! Their coatings have been tested and approved by third party labs.Have a question about ASTM standards? The fireproofing experts at FlameOFF Coatings are standing by to answer your questions.
In the next section, we’ll recommend intumescent paints or steel and wood. This video provides an excellent primer too how intumescent works on these types of materials.
Intumescent Paint For Steel
Our Top Pick: FlameOFF’s Fire Barrier Paint
Summary: Fire Barrier Paint from FlameOFF provides long-lasting fireproof protection for a wide variety of substrates and materials, including steel and other metals. It’s our #1 recommended product.
Product features:
- Environmentally friendly
- E84 compliant
- E119 compliant and fire rated for up to two hours
- Multi-surface use, including wood, metal, sheetrock, and drywall
- Gold Supplier Member of National Fireproofing Contractors Association
You can download FlameOFF’s Product Brochures and Safety Data Sheets here.
Thermo-Sorb 263
Summary: This Carboline product is a solvent-based intumescent paint that protects interior structural steel. It’s well-suited for use with interior steel beams, pipes, and columns.
Product features:
- Durable, dust-free surface
- Good-looking smooth finish
- Compliant with VOC requirements
Fire rating: Up to four hours, depending on the structure users apply it to.
Product data sheet available for download here. For more about Carboline, read our review of Carboline’s most popular products.
Firetex FX5120
Summary: From Sherwin-Williams’ Firetex brand, this intumescent coating is a water-based option. It’s great for exposed structural steel in interior settings.
Product features:
- Paint-like finish
- Resistant to impact
- Applies well to substrates
Fire rating: Up to two hours fire protection.
Product data sheet available here.
STEELGUARD 550
Summary: PPG’s STEELGUARD line helps protect steel substrates from cellulosic fires. This coating is a one-component, solvent-borne coating created with structural steelwork in mind.
Product features:
- Apply on-site or off-site
- Weather-resistant for up to a year
- Matte finish
Fire rating: Up to 150 minutes cellulosic fire protection.
Product data sheet available here.
Intumescent Paint For Drywall (Gypsum)
Our Top Pick: FlameOFF’s Fire Barrier Paint
Summary: Fire Barrier Paint from FlameOFF is particularly well-suited for drywall. When tested by a third party lab, Fire Barrier Paint achieved over 2 hours of fire rated protection (many brands only provide a 1-hour rating for materials like drywall).
No matter your drywall needs, FlameOFF Barrier Paint is an excellent option.
Product features
- 2-hour fire rating for drywall (i.e. sheetrock, gypsum, plasterboard, wallboard, etc.)
- Compatible with a variety of drywall shapes and sizes (e.g. Type X, Type C, etc.)
- Certified ASTM E119, ASTM E84, NFPA 251, and ULC CAN S-101
- Suited for mixed use environments with commercial and residential space
You can find FlameOFF’s Fire Barrier Paint product brochures and safety data sheets for drywall here.
Intumescent Paint For Wood
Wood is a combustible material. A fire can quickly erupt and cause irreparable damage to your facility and the people inside. While intumescents can’t necessarily stop a fire, they can prevent catastrophic structural failure. Below you’ll find our recommended intumescent paints for wood materials.
Our Top Pick: FlameOFF’s Fire Barrier Paint
Summary: Fire Barrier Paint from FlameOFF provides long-lasting fireproof protection for a wide variety of wood materials and structures.
Product features:
- Environmentally friendly
- E84 compliant
- E119 compliant and fire rated for up to one hour on wood
- Compatible with both wood, steel, and several other materials
You can find FlameOFF’s Fire Barrier Paint product brochures and safety data sheets here.
FX-100
Summary: Flame Seal Products, Inc., a company specializing in fire-resistant coatings, sells this coating. It has a lower activation temperature than other intumescent paints – use it with wood or plastic.
Product features:
- Clear coating
- Safe to handle
- Easy to apply
Fire rating: Provides Class A or Class B protection when applied correctly.
Product data sheet available here.
FireGuard E-84 Intumescent Coating
Summary: A Shield Industries, Inc. product, this water-based coating can protect a wide variety of substrates. The materials it’s compatible with include wood, steel, and many others.
Product features:
- Low VOC levels
- Durable, decorative finish
- Thin film coating
Fire rating: Tested to various fire resistance standards. Up to two hours fire protection when applied to a heavy steel column.
Product data sheet available here.
DC360 Fireproof Paint
Summary: International Fireproof Technology, Inc. sells intumescent paints that can help boost your structure’s fire resistance rating. This water-based intumescent coating is especially suited for use with wood and gypsum.
Product features:
- Apply with spray, roll, or brush
- Non-toxic and hypoallergenic
- Flat finish
Fire rating: Provides Class A fire protection in accordance with ASTM E84. Can protect combustible substrates from fire for up to 30 minutes.
Product data sheet available here.
Related article: Best Fire Resistant & Fire Retardant Paints in 2022
Intumescent Paint – Frequently Asked Questions
Intumescent paints are required when materials in your building (e.g. walls, structural steel, ceilings, etc.) need to meet ASTM E-119 standards.
Intumescent paint costs $4 to $12 per square foot. It’s relatively expensive compared to cheaper options like cementitious coatings.
Intumescent paint is typically applied with a paint sprayer, but it can also be applied with a paint brush or roller depending on the manufacturer’s specifications.
Most intumescent paints require a primer unless the manufacturer indicates it is a 2-in-1 solution with a primer and top coat. Check your coating’s technical specs!
Yes, most intumescent paints can be applied with a brush, roller, or paint sprayer.
The key to a smooth finish actually starts with surface preparation. Make sure to clean the area of dust, debris, and rust with a material blaster or pressure washer before applying your intumescent paint.
Intumescent paints will protect your asset during a fire between 30 minutes up to 4 hours, depending on the material and coating specification.
Intumescent paints are more aesthetically pleasing and more versatile than cementitious coatings.
It usually takes between 2 – 8 hours for an intumescent paint to fully dry, but this will vary by application, coating thickness, and jobsite conditions.
Yes. Intumescent paints are designed to improve ASTM E-119 fire ratings to meet ICS building code compliance.