Paint Type
Intumescent Paint
Intumescent paint is a passive fire-protection coating formulated to expand when exposed to high heat and form an insulating char layer over the substrate. Its fire performance depends on the complete tested coating system, substrate, required dry-film thickness, application, and specified fire-resistance rating.
Intumescent paint compatibility
Intumescent coatings are used on substrates such as structural steel, wood, drywall, and concrete, but compatibility alone does not establish a fire rating. The exact tested assembly, primer, intumescent layer, topcoat, film thickness, and installation requirements must match the intended fire-protection specification.
| Surface | Compatibility | Preparation | Primer or ground | Finish | Guide |
|---|---|---|---|---|---|
| Metal | Excellent for structural steel when part of an approved intumescent system | Prepare steel to the coating manufacturer's specified cleanliness and profile, removing rust, scale, oil, grease, and incompatible coating. | Use only the primer approved for the tested intumescent system. | Apply the required dry-film thickness and compatible topcoat, if specified, to achieve the designed fire-protection performance. | — |
| Wood | Good when the exact intumescent system is tested and approved for the wood assembly | Use sound, dry, clean wood and follow the system's requirements for existing finishes, moisture, sanding, and repairs. | Use only the primer or base coat specified for the tested wood system. | Required coating thickness and any protective topcoat must follow the approved fire-protection specification. | — |
| Drywall | Good when included in a tested intumescent wall or ceiling system | Repair damaged board or joints, remove dust and contamination, and make sure the assembly matches the specified substrate condition. | Use only the primer or sealer approved by the intumescent coating system. | Do not infer a wall fire rating from the coating alone; the complete tested assembly and specified film thickness control performance. | — |
| Concrete | Good when the intumescent system is approved for the concrete assembly | Use cured, sound, dry concrete and remove dust, laitance, contamination, loose material, and incompatible coatings as specified. | Use the compatible primer or sealer required by the tested coating system. | Apply and inspect the specified film thickness and any required topcoat as part of the complete passive-fire-protection system. | — |
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