Methods of Fire Protection

There are a few different methods of fire protection available to achieve the required FRL on structures.

Fire rated boards can be framed around steel or timber structures in order to fire protect structural members. The composition of boards will differ between manufactures however their general composition is made up of processed gypsum.

Advantages

  • Relatively low material cost
  • Provides a smooth even surface for finishing
  • Provides acoustic performance

Disadvantages

  • Requires fitting of tracks and clips to steel elements to fix boards to
  • A more labour intensive system to install, thus longer time frame on work site floors
  • Boards have thicknesses ranging from 13mm to 30mm so can add significant weight
  • Multiple layers of board may be required depending on the fire rating level required thus encroaches on available space
  • Not suitable for complex configurations
  • Requires patching and finishing of screw holes and setting of corners/edges
  • Not suitable for external use or in damp or high humidity internal environments

 

Vermiculite is a low cost wet cementitious fire rating material which is spray applied. It has been used in structural steel fire protection for decades. The system can only be used for internal environments as it is susceptible to damage by water ingress.

Advantages

  • Low cost
  • Economical – high yield – low density
  • Monolithic coating
  • Can be applied directly to steel

Disadvantages

  • Can only be used for internal protected environments as it will be damaged by water ingress
  • Is a ‘wet’ trade and other trades can not work in areas during vermiculite application or have contact with the applied coating until fully cured, which can take some days depending on prevailing weather conditions
  • Requires a relatively large application equipment footprint
  • Creates a considerable amount of overspray to all surrounding surfaces and may require specific masking and protection
  • Is a quite porous material even when cured and if steel is not primed prior to vermiculite application, corrosion can occur
  • Can damage relatively easy
  • If not pinned and meshed when installed, differential movement of sprayed steel can cause cracking and dislodgement of the vermiculite

 

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.

 

Intumescent Type Advantages Disadvantages
Solvent based
  • 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
  • If applied on-site it can be damaged by water if not fully cured
  • Has high VOC’s 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
Water based
  • 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
  • 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
Epoxy based
  • 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
  • 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
Hybrid
  • 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
  • Has a lightly textured finish ‘off the gun’ which may require additional attention to achieve a high level finish

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Disclaimer: Permax is a supplier of various fire protection products that are manufactured in global locations. The Permax advisory notes are developed to assist the professions in the Australian construction industry with their passive fire protection design. If you are unsure about the content of the documents or if you have any project specific enquiries, please contact the Permax Technical Team for further assistance.

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Permax constantly update the documentations based on the new fire testing outcomes and change of standards and regulations. To ensure the documents you read are up-to-date, please contact the Permax technical team.