We are experts in the application of intumescent coatings and can provide detailed advice on their function and application.

Expanded thin film intumescent coating

Intumescent coatings are paint-like substances that are inert at low-temperature ranges yet supply insulation because of an intricate chemical effect at temperature ranges generally around 200-250°C. In these conditions, the qualities of steel are not impacted. Due to this particular reaction, they expand and offer an extended coating of reduced conductivity char.

Intumescent coatings are generally split into 2 broad types: thin film and thick film. Thin-film products can be solvent-based or water-based and are mostly employed for cellulosic fire situations. Thick film intumescent coatings were initially produced for the off-shore and hydrocarbon sectors but have been customized for use in buildings.

Thin-film intumescent coatings

Thin-film intumescent coating products usually have 3 elements, a primer, a basecoat (the component that functions in the flames) along with a sealant layer. The basecoat normally consists of these elements:

• A catalyst that breaks down to generate a mineral acid like phosphoric acid.
• A carbonific-like starch that mixes with the mineral acid produces a carbonaceous char.
• A binder or resin that softens at a set heat level.
• A spumific agent that breaks down along with the melting of the binder, to free significant quantities of non-flammable gases. These gases consist of co2, ammonia, and water vapour. The creation of these gases will cause the carbonaceous char to expand or foam and enlarge to offer an insulation coating several times the initial layer thickness.

These are primarily utilized in buildings where the fire resistance specifications are 30, 60, and 90 minutes. Nowadays, several systems have been formulated that can deliver Two hours fire resistance. They may be applied either on-site or off-site.

Normally, almost all on-site application is done employing water-based products. Nonetheless, where the structure to which the material is used is not to have an end-use in a dry, heated (C1) situation, solvent-based materials are generally implemented. Solvent-based materials likewise are often able to protect a broader range of section factors than water-based materials and can be used on-site to safeguard smaller-sized areas demanding high thicknesses.

Both solvent-based and water-based coatings may be used to attain appealing surface finishes. If a creative or custom finish is needed, this ought to be included in the specification. Thin-film intumescents possess the extra benefits that they can conveniently go over intricate shapes and post-protection support installation is fairly straightforward.

Standard expansion ratios are about 50:1, i.e. a 1mm thick layer can enlarge to around 50mm whenever impacted by fire.

Comprehensive advice on the standards and application of site applied, thin-film intumescent coatings can be obtained from the Association for Specialist Fire Protection

Thick Film

Thick film intumescent coatings are generally epoxy-based and frequently have a significantly higher dry film thickness compared to thin-film options. These types of products are robust and sturdy and were initially produced for use with hydrocarbon fires, in which the test heating regimen is a lot more extreme compared to that employed for the majority of industrial and business purposes. Several suppliers have customised their products for usage in cellulosic fires. These types of customized products are generally utilized in circumstances in which the advantages of intumescent coatings regarding the visual appeal, weight, and thickness are needed but where conditions are too extreme, or servicing too hard, to permit using thin-film products. Typical recent instances have taken place in exterior steel in high-rise structures and exposed marine situations.

Expansion ratios for thick film intumescents are a lot less than for thin-film materials, usually around 5:1. Artistic surface finishes are achievable and they can even be delivered by way of preformed casings. Thick film intumescent coatings can also be applied off-site.