Intumescent coating types

There are a variety of intumescent coating types with different properties and application methods. Which type is the best for your situation?

Intumescent is the newest fire protection methodology to come onto the market. Unlike boards and vermiculite, intumescent is a reactive material which expands to insulate structural steel in a fire event. Every intumescent has different material properties and therefore have different required thicknesses and expansion behaviour.

In 2013, the first ‘hybrid’ intumescent coating, Nullifire SC900 series, SC901 and SC902 was released. This technology combined the advantages of ‘thin film’ intumescent in respect to coating thickness and also introduced unique product performance characteristics that stood it apart from all other conventional intumescent coatings.

Solvent-based systems

Solvent-based coatings usually used in semi-exposed environments and are tested against weather and temperature variations. Solvent-based coatings tend to be more resistant to weather conditions as well as temperature changes and humidity. They also dry faster and have a smoother finish.

Advantages
  • Suitable for internal steel or semi-exposed and exposed steel work when top sealed
  • Can be applied off-site or on-site
  • Relatively hard film when fully cured
Disadvantages
  • If applied on-site it can be damaged by water if not fully cured
  • Has high VOCs which can be an OH&S issue if applied on-site
  • Requires multiple applications to achieve higher film builds
  • Curing could take between 5 and 15 days depending on ambient conditions and film build
Example products
Jotun Steelmaster 60SB

Water-based systems

Water-based intumescent coatings are a generally more eco-friendly and less "chemically-smelling" option. They are the least expensive and produce less odour, however these coatings are less tolerant to humidity and low temperatures and therefore may take longer to completely cure in such environments.

Advantages
  • Very Low VOC
  • Low odour so does not impact on other trades when applied on-site
  • Can be applied to a smooth finish
  • Relatively simple to repair
Disadvantages
  • Can only be applied on-site in fully protected areas
  • Very sensitive to high humidity or moisture
  • Requires multiple applications to achieve higher film builds
  • Curing could take between 5 and 15 days depending on ambient conditions and film build
  • Can be prone to damage easily
Further reading - permax.com.au/water-based-intumescents-what-you-need-to-know
Example products
Nullifire SC80X range
Akzo Nobel Interchar range

Epoxy-based systems

Epoxy-based intumescent is typically used in harsher environments such as the offshore marine industries or the chemical industry because these coatings provide excellent hydrocarbon fire protection. Epoxy-based intumescent comes in two-parts which when combined, forms a very thick and durable film that insulates the steel member and is highly resistant to corrosion.

Advantages
  • Low VOC
  • Cures to a very hard durable finish
  • Suitable for application for both internal and external steel work
  • Generally applied off-site
  • Relatively resistant to damage when handled or transported
Disadvantages
  • Not generally suited to on-site application due to more complex application equipment requirement
  • More expensive product in comparison to conventional intumescent coatings
  • Higher film builds require multiple applications over several days
  • Cured epoxy intumescent although hard can be brittle and be susceptible to impact damage
  • Cured epoxy intumescent can crack and delaminate if coated steel deflects
Example products
Jotun Steelmaster 1200HPE

Hybrid systems

In 2014, a new technology emerged in the field of intumescent coatings - hybrid intumescent coatings. This technology was developed to provide faster cure times without multiple coats, while still delivering the same level of fire protection and ratings.

Advantages
  • Low VOC
  • Suitable for both internal and external steel fire protection
  • Suitable for both on-site and off-site application
  • Ultra-high build – 60% faster with single application to achieve all fire ratings
  • Rapid curing time – early weather resistance within 1 hour of application
  • Very surface tolerant: can be applied directly to blasted steel or flash rusted steel
  • Tolerates high humidity : 85%+ or low temperatures: cures down to 0˚C
  • Durable flexible film: resists impact damage
  • Easy to repair
  • Good aesthetics: can be top sealed for decorative or protective finish
Disadvantages
  • Has a lightly-textured finish "off the gun" which may require additional attention to achieve a high level finish
Example products
Nullifire SC902

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Intumescent coatings
Passive fire protection
Passive fire protection methods

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Intumescent coatings
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Off-site versus on-site application

Nullifire SC902 ‘hybrid’ intumescent coating system - one of our preferred ‘hybrid’ intumescent coating systems - is based on patented technology that delivers exceptional productivity gains for both on-site and off-site applications, in comparison with conventional intumescent coatings used for structural steel fire protection.

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Intumescent paint coating specification templates

Access a range of templates supplied by manufacturers for the purposes of specifying their intumescent paint coating products for various FRLs and corrosivity ratings.

Intumescent coatings
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Intumescent paint coating corrosivity ratings in the Australian atmosphere

It's common knowledge that corrosion rates are affected by environmental factors, but do you know the various corrosivity ratings and their definitions?

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Limiting steel temperatures to maintain structural integrity

Maintaining structural adequacy on load-bearing steel is critical to the fire safety of building occupants, fire fighters and the surrounding built environment. Here's how limiting steel temperatures to maintain structural integrity relates to intumescent paint coatings.

Intumescent coatings
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Getting help with intumescent paint coatings

The specifying and application of an intumescent coating system is a highly specialised task that requires considerable training and experience to accomplish correctly.

Intumescent coatings
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Fire types and severity

Different combustible materials burn at different temperatures which will have a bearing on the FRL of a given intumescent paint coating. This needs to be taken into account when specifying intumescent products so that the required FRL is ensured for the combustible materials that are likely to be encountered in a particular situation.

Intumescent coatings
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Quality assurance for intumescent paint coatings

We believe Painting Contractor Certification Program (PCCP) accreditation is paramount for passive fire protection contractors engaged in applying intumescent paint coating systems.

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Specifying intumescent paint coatings

Whilst intumescent coating products may look just like paint, they have an important function (i.e. passive fire protection) that makes their specification a much more involved process.

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How core filling affects intumescent paint coatings

Core filling is a viable solution to fire-protect high Hp/A hollow section steel that is otherwise unable to achieve the desired FRL.

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