What Does Passive Fire Protection Coating (PFP Coating) Mean?
A passive fire protection coating (PFP coating) is a protective barrier applied to an industrial component that prevents damage during a fire. By being passive, the coating protects against the negative effects of a fire, but does not quench or prevent the spread of a fire as active fire protection might.
A passive fire protection coating is one of several types of fire protection coatings, which also include cementitious products, blanket systems and fiberboard systems. PFP coatings are generally intumescent materials and some are part of an epoxy formulation.
PFP coatings may also be prone to corrosion under insulation (CUI). These factors should be considered when choosing the appropriate coating formulation.
Corrosionpedia Explains Passive Fire Protection Coating (PFP Coating)
PFP coatings protect materials such as steel by slowing down the rate at which the steel is heated, ideally keeping the material below the point where it loses strength and becomes damaged. By slowing the rate, the facility may have enough time to extinguish the fire before irreversible damage occurs. PFP coatings may be characterized by their maximum time of fire resistance, such as 60 minutes.
Intumescent PFP coatings work by reacting at a high temperature, causing the material to swell into a char with low thermal conductivity. The material thus slows the rate at which the encased steel heats and slows the damaging effects of the fire. There are two families of intumescent PFP coatings:
- Thin film intumescent coatings - Consist of a primer, a basecoat and a sealer coat
- Thick film intumescent coatings - Based on an epoxy formulation
The protective thick char is the result of complex chemical reactions. The coating contains an acidic compound that catalyzes the necessary reactions. The carbon char is produced by the acid reacting with a carbonific material. Meanwhile, the acid also reacts with a spumific, foam-producing agent, which releases non-toxic gases. The gas formation is responsible for the material's swelling. Thin film coatings typically expand by a factor of 50 when exposed to fire, but thick film coatings typically only expand by a factor of 5.