What are intumescent coatings?
Intumescent coatings provide an appearance similar to that of a paint finish. At ambient temperatures, they remain stable. However, in a fire situation, the increase in temperature causes a chemical reaction.
The intumescent coating expands to many times its original thickness. This provides an insulating foam-like coating or “char” which protects the substrate.
The intumescent coating is designed to insulate the steel, and prevent the temperature of the steel from rising to a critical point at which structural failure becomes possible.
Protecting timber structures
Timber structures are more susceptible to the surface spread of flame and heat propagation. Intumescents are designed to reduce heat propagation, and reduce the spread of flame.
How do intumescents work?
The expansion process is caused by the interaction of three precisely formulated components:
|Carbon supplier||Polyols as starch, pentaerythritol|
|Acid source||Ammonium polyphosphate|
|Note||These components are bound in a solvent or water-borne polymeric binder. Other components are added to improve the paint properties, enable easy application, enhance build and achieve faster drying.|
Typical intumescent process
As heat is applied the chemical reaction begins:
The heat begins to soften the polymeric binder.
It also causes an organic acid to be released from the Ammonia Polyphosphate.
Carbonisation of the polyols begins.
As the blowing agent (melamine) decomposes, gas is produced which swells the molten mixture.
Finally, the foamed char solidifies, through a cross-linking reaction, to maintain the insulation.
In an ideal situation, intumescent can expand to around 100 times its original thickness. To achieve this requires careful selection of formulation components and precise matching of processes involved.
Storage and Handling:
Store the paint in proper conditions as per the local regulations. Keep the paint container in sealed condition under shed, away from direct sunlight and extreme temperatures. Don’t stock paint material near to any ignition sources. Don’t put back the half or unused material back in original container containing the supplies paint, to avoid contamination. Handle with care. Stir well before use.
|Color, dry film||White or cool green|
|Finish, dry film||Smooth / Matt|
|Solids (by weight)||66±2%|
|Theoretical spreading||2.70M 2 / Ltr – 1.8M 2 / Ltr|
|Recommended DFT (dry film)||200-300Microns/Coat|
|Recommended WFT (wet film)||370-555 Microns/Coat|
|Fire resistance time||Up to 4hours|
|Note||An experienced applicator can apply up to 680 microns per coat using airless sprayer.|
|Temperature||Touch dry||Dry to recoat||Hard dry|
|10 ºC（50 ºF）||6hours||24hours||Unlimited|
|15 ºC（59 ºF）||5hours||24hours||Unlimited|
|25 ºC（77 ºF）||4hours||20hours||Unlimited|
|40 ºC（104 ºF）||3hours||18hours||Unlimited|
|Shelf life at 30ºC||6 months, in original sealed container, with proper storage conditions. Store in dry and cool place (5-35ºC)|
|Application method||Airless sprayer, brush, roller|
|Cleaning / thinning||Water|
|Thinner (volume)||Ready to use, when applied by spray equipment, otherwise and if necessary, use up to 10% thinning with water.|
|CONV. Spray requirements||Possible|
|Airless spray requirements||Pressure: 120-150bar (1700-2125psi)|
|Mixing ratio (by volume)||One pack|
Ideal for oil-based and water-based fireproofing materials painting (about 1mm thickness each layer).
Two guns spraying at the same time is available, high efficiency, save more working time.
|Model No.||DP-6337ib with brushless motor|
|Pressure control||Electronical + digital|
|Max. flow rate||7L/min|
|Max. tip size (1 gun)||0.043”|
|Max. tip size (2 guns)||0.027”|
|Max. spraying pressure||120bar/1740psi(0.041”)|
Language in: Dutch
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