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interior · low odour
Water-based
Low VOC, for dry interiors and occupied buildings – offices, schools, retail.
Fire protection · Intumescent coatings
Intumescent coatings – slim fire protection that keeps steel visible
An intumescent coating looks like paint, but in a fire it swells up to dozens of times its thickness into a carbon char that insulates the steel. It is the preferred fire protection for exposed and architectural steel – and it can be applied in the factory, so steel arrives on site ready to erect.
- R30 – R120
- Typical cellulosic ratings thin-film coatings
- Up to ≈ 50 ×
- Expansion in fire product-dependent
- ≈ 200 – 250 °C
- Typical activation reaction starts
- Shop or site
- Application airless spray, brush, roller
How an intumescent coating works
The coating system has three layers: an anti-corrosion primer, the intumescent basecoat and a topcoat for colour and protection. When the coating is heated, chemical reactions release gases that blow the softened binder into a thick, foamed char. The char has very low thermal conductivity and slows the rise of steel temperature.
The required dry film thickness (DFT) is taken from the product's tested and assessed data for each member – using its section factor, the critical temperature and the required fire rating. Thin-film products cover cellulosic (building) fires; thick-film epoxy systems are made for the faster, hotter hydrocarbon fires of oil, gas and petrochemical plants.
Product range
Intumescent coating types
Product-type pages with typical data – brand and listed system per specification.
Intumescent coatings for cellulosic fires
Thin-film water-based and solvent-based coatings for steel in buildings – ratings typically R30 to R120.
Thin-film · cellulosicWater-based intumescent coatingA low-odour, water-borne thin-film coating for steel in dry interiors – offices, schools, shopping centres and car parks with a protective topcoat.Cellulosic (building)Fire typeR30 – R120Typical ratingView product →
Thin-film · cellulosicSolvent-based intumescent coatingA fast-drying, humidity-tolerant thin-film coating – the usual choice for shop-applied fire protection on export projects.Cellulosic (building)Fire typeR30 – R120Typical ratingView product →Intumescent · exterior exposureExterior-grade intumescent systemsSteel outside the building envelope needs an intumescent system proven to keep its fire performance after weathering.Exterior / semi-exposedExposureEAD 350402 type X or YDurabilityView product →Epoxy intumescent coatings for hydrocarbon fires
Thick-film epoxy systems for oil & gas, petrochemical and offshore steel – hydrocarbon and jet-fire scenarios.
Types
Three families of intumescent coatings
Typical properties – each brand's assessed data defines the actual thickness.
interior · low odour
shop-applied · fast drying
Solvent-based
Faster drying and more humidity-tolerant – the usual choice for off-site application.
hydrocarbon · C5
Epoxy (thick film)
Hard, durable systems for oil & gas, LNG and offshore steel – hydrocarbon and jet fire.
Codes & compliance
Standards for intumescent coatings
Most often specified in our export markets.
Europe
- EN 13381-8Test methods for reactive protection applied to steel members
- EAD 350402-00-1106European assessment of reactive coatings (ETA / CE marking)
- EN 1363-2Hydrocarbon fire curve
United States
- UL 263 · ASTM E119Fire resistance of building construction (UL design listings)
- UL 1709Rapid-rise hydrocarbon fire for structural steel
- ISO 22899-1Jet fire resistance
Australia & New Zealand
- AS 1530.4 · AS 4100Fire-resistance tests; steel fire design
- AS 4312 / ISO 12944Corrosivity categories for the coating system
Summary for orientation only – the project specification, the adopted code edition and the authority having jurisdiction govern.
World Steel painting shop
Fire protection applied in the factory
World Steel blasts the steel to the specified surface grade, applies a compatible primer and the intumescent basecoat to the fire engineer's thickness schedule, then records the dry film thickness of each member in the coating report. Members are packed with protection at lifting points and supports; a touch-up kit and procedure travel with the shipment. See fire protection for structural steel.
Advantages and limitations
Is an intumescent coating right for your steel?
| Advantage | Why it matters |
|---|---|
| Slim and decorative | The steel's shape stays visible – ideal for architectural steel |
| Off-site application | Fewer site trades; steel arrives protected |
| Light weight | No extra load on the structure |
| Covers complex details | Connections, cellular beams and hollow sections |
| Limitation | What to do |
|---|---|
| Cost rises at long ratings | Above ≈ 90–120 min compare boards or sprays |
| Damage in transport | Careful packing, touch-up procedure on site |
| Humidity and exposure | Choose the right type and an approved topcoat |
| Thickness is critical | Measure and record DFT for every member |
FAQ
Frequently asked questions
How thick is an intumescent coating?
Typically from a few tenths of a millimetre to a few millimetres of dry film for building fires – set member by member from the product's assessed data.
Can intumescent coatings be used outdoors?
Some products are approved for exterior or semi-exposed use with a specific topcoat; epoxy systems are made for harsh exterior and offshore conditions.
Is the coating applied in the factory or on site?
Both are possible. Factory application gives better control of thickness and saves site time; damaged areas are touched up after erection.
How is the coating checked?
Dry film thickness is measured on each member and recorded against the schedule; the inspector compares it with the required thickness.
Steel delivered with its fire protection
Send the member schedule and fire ratings – we quote steel and intumescent coating together.